1 | NAME |
1 | NAME |
2 | IO::AIO - Asynchronous Input/Output |
2 | IO::AIO - Asynchronous/Advanced Input/Output |
3 | |
3 | |
4 | SYNOPSIS |
4 | SYNOPSIS |
5 | use IO::AIO; |
5 | use IO::AIO; |
6 | |
6 | |
7 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
7 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
8 | my $fh = shift |
8 | my $fh = shift |
9 | or die "/etc/passwd: $!"; |
9 | or die "/etc/passwd: $!"; |
10 | ... |
10 | ... |
11 | }; |
11 | }; |
12 | |
12 | |
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23 | my $req = aio_unlink "/tmp/file", sub { }; |
23 | my $req = aio_unlink "/tmp/file", sub { }; |
24 | $req->cancel; # cancel request if still in queue |
24 | $req->cancel; # cancel request if still in queue |
25 | |
25 | |
26 | my $grp = aio_group sub { print "all stats done\n" }; |
26 | my $grp = aio_group sub { print "all stats done\n" }; |
27 | add $grp aio_stat "..." for ...; |
27 | add $grp aio_stat "..." for ...; |
28 | |
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29 | # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) |
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30 | use AnyEvent::AIO; |
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31 | |
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32 | # EV integration |
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33 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
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34 | |
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35 | # Event integration |
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36 | Event->io (fd => IO::AIO::poll_fileno, |
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37 | poll => 'r', |
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38 | cb => \&IO::AIO::poll_cb); |
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39 | |
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40 | # Glib/Gtk2 integration |
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41 | add_watch Glib::IO IO::AIO::poll_fileno, |
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42 | in => sub { IO::AIO::poll_cb; 1 }; |
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43 | |
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44 | # Tk integration |
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45 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
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46 | readable => \&IO::AIO::poll_cb); |
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47 | |
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48 | # Danga::Socket integration |
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49 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
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50 | \&IO::AIO::poll_cb); |
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51 | |
28 | |
52 | DESCRIPTION |
29 | DESCRIPTION |
53 | This module implements asynchronous I/O using whatever means your |
30 | This module implements asynchronous I/O using whatever means your |
54 | operating system supports. It is implemented as an interface to "libeio" |
31 | operating system supports. It is implemented as an interface to "libeio" |
55 | (<http://software.schmorp.de/pkg/libeio.html>). |
32 | (<http://software.schmorp.de/pkg/libeio.html>). |
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78 | not well-supported or restricted (GNU/Linux doesn't allow them on normal |
55 | not well-supported or restricted (GNU/Linux doesn't allow them on normal |
79 | files currently, for example), and they would only support aio_read and |
56 | files currently, for example), and they would only support aio_read and |
80 | aio_write, so the remaining functionality would have to be implemented |
57 | aio_write, so the remaining functionality would have to be implemented |
81 | using threads anyway. |
58 | using threads anyway. |
82 | |
59 | |
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60 | In addition to asynchronous I/O, this module also exports some rather |
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61 | arcane interfaces, such as "madvise" or linux's "splice" system call, |
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62 | which is why the "A" in "AIO" can also mean *advanced*. |
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63 | |
83 | Although the module will work in the presence of other (Perl-) threads, |
64 | Although the module will work in the presence of other (Perl-) threads, |
84 | it is currently not reentrant in any way, so use appropriate locking |
65 | it is currently not reentrant in any way, so use appropriate locking |
85 | yourself, always call "poll_cb" from within the same thread, or never |
66 | yourself, always call "poll_cb" from within the same thread, or never |
86 | call "poll_cb" (or other "aio_" functions) recursively. |
67 | call "poll_cb" (or other "aio_" functions) recursively. |
87 | |
68 | |
88 | EXAMPLE |
69 | EXAMPLE |
89 | This is a simple example that uses the EV module and loads /etc/passwd |
70 | This is a simple example that uses the EV module and loads /etc/passwd |
90 | asynchronously: |
71 | asynchronously: |
91 | |
72 | |
92 | use Fcntl; |
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93 | use EV; |
73 | use EV; |
94 | use IO::AIO; |
74 | use IO::AIO; |
95 | |
75 | |
96 | # register the IO::AIO callback with EV |
76 | # register the IO::AIO callback with EV |
97 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
77 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
98 | |
78 | |
99 | # queue the request to open /etc/passwd |
79 | # queue the request to open /etc/passwd |
100 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
80 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
101 | my $fh = shift |
81 | my $fh = shift |
102 | or die "error while opening: $!"; |
82 | or die "error while opening: $!"; |
103 | |
83 | |
104 | # stat'ing filehandles is generally non-blocking |
84 | # stat'ing filehandles is generally non-blocking |
105 | my $size = -s $fh; |
85 | my $size = -s $fh; |
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114 | |
94 | |
115 | # file contents now in $contents |
95 | # file contents now in $contents |
116 | print $contents; |
96 | print $contents; |
117 | |
97 | |
118 | # exit event loop and program |
98 | # exit event loop and program |
119 | EV::unloop; |
99 | EV::break; |
120 | }; |
100 | }; |
121 | }; |
101 | }; |
122 | |
102 | |
123 | # possibly queue up other requests, or open GUI windows, |
103 | # possibly queue up other requests, or open GUI windows, |
124 | # check for sockets etc. etc. |
104 | # check for sockets etc. etc. |
125 | |
105 | |
126 | # process events as long as there are some: |
106 | # process events as long as there are some: |
127 | EV::loop; |
107 | EV::run; |
128 | |
108 | |
129 | REQUEST ANATOMY AND LIFETIME |
109 | REQUEST ANATOMY AND LIFETIME |
130 | Every "aio_*" function creates a request. which is a C data structure |
110 | Every "aio_*" function creates a request. which is a C data structure |
131 | not directly visible to Perl. |
111 | not directly visible to Perl. |
132 | |
112 | |
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168 | anymore (except possibly for the Perl object, but its connection to |
148 | anymore (except possibly for the Perl object, but its connection to |
169 | the actual aio request is severed and calling its methods will |
149 | the actual aio request is severed and calling its methods will |
170 | either do nothing or result in a runtime error). |
150 | either do nothing or result in a runtime error). |
171 | |
151 | |
172 | FUNCTIONS |
152 | FUNCTIONS |
173 | AIO REQUEST FUNCTIONS |
153 | QUICK OVERVIEW |
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154 | This section simply lists the prototypes most of the functions for quick |
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155 | reference. See the following sections for function-by-function |
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156 | documentation. |
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157 | |
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158 | aio_wd $pathname, $callback->($wd) |
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159 | aio_open $pathname, $flags, $mode, $callback->($fh) |
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160 | aio_close $fh, $callback->($status) |
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161 | aio_seek $fh,$offset,$whence, $callback->($offs) |
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162 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
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163 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
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164 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
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165 | aio_readahead $fh,$offset,$length, $callback->($retval) |
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166 | aio_stat $fh_or_path, $callback->($status) |
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167 | aio_lstat $fh, $callback->($status) |
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168 | aio_statvfs $fh_or_path, $callback->($statvfs) |
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169 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
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170 | aio_chown $fh_or_path, $uid, $gid, $callback->($status) |
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171 | aio_chmod $fh_or_path, $mode, $callback->($status) |
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172 | aio_truncate $fh_or_path, $offset, $callback->($status) |
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173 | aio_allocate $fh, $mode, $offset, $len, $callback->($status) |
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174 | aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents) |
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175 | aio_unlink $pathname, $callback->($status) |
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176 | aio_mknod $pathname, $mode, $dev, $callback->($status) |
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177 | aio_link $srcpath, $dstpath, $callback->($status) |
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178 | aio_symlink $srcpath, $dstpath, $callback->($status) |
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179 | aio_readlink $pathname, $callback->($link) |
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180 | aio_realpath $pathname, $callback->($path) |
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181 | aio_rename $srcpath, $dstpath, $callback->($status) |
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182 | aio_rename2 $srcpath, $dstpath, $flags, $callback->($status) |
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183 | aio_mkdir $pathname, $mode, $callback->($status) |
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184 | aio_rmdir $pathname, $callback->($status) |
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185 | aio_readdir $pathname, $callback->($entries) |
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186 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
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187 | IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST |
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188 | IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN |
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189 | aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) |
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190 | aio_load $pathname, $data, $callback->($status) |
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191 | aio_copy $srcpath, $dstpath, $callback->($status) |
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192 | aio_move $srcpath, $dstpath, $callback->($status) |
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193 | aio_rmtree $pathname, $callback->($status) |
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194 | aio_fcntl $fh, $cmd, $arg, $callback->($status) |
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195 | aio_ioctl $fh, $request, $buf, $callback->($status) |
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196 | aio_sync $callback->($status) |
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197 | aio_syncfs $fh, $callback->($status) |
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198 | aio_fsync $fh, $callback->($status) |
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199 | aio_fdatasync $fh, $callback->($status) |
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200 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
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201 | aio_pathsync $pathname, $callback->($status) |
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202 | aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status) |
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203 | aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
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204 | aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
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205 | aio_mlockall $flags, $callback->($status) |
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206 | aio_group $callback->(...) |
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207 | aio_nop $callback->() |
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208 | |
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209 | $prev_pri = aioreq_pri [$pri] |
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210 | aioreq_nice $pri_adjust |
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211 | |
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212 | IO::AIO::poll_wait |
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213 | IO::AIO::poll_cb |
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214 | IO::AIO::poll |
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215 | IO::AIO::flush |
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216 | IO::AIO::max_poll_reqs $nreqs |
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217 | IO::AIO::max_poll_time $seconds |
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218 | IO::AIO::min_parallel $nthreads |
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219 | IO::AIO::max_parallel $nthreads |
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220 | IO::AIO::max_idle $nthreads |
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221 | IO::AIO::idle_timeout $seconds |
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222 | IO::AIO::max_outstanding $maxreqs |
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223 | IO::AIO::nreqs |
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224 | IO::AIO::nready |
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225 | IO::AIO::npending |
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226 | IO::AIO::reinit |
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227 | |
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228 | $nfd = IO::AIO::get_fdlimit [EXPERIMENTAL] |
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229 | IO::AIO::min_fdlimit $nfd [EXPERIMENTAL] |
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230 | |
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231 | IO::AIO::sendfile $ofh, $ifh, $offset, $count |
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232 | IO::AIO::fadvise $fh, $offset, $len, $advice |
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233 | |
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234 | IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] |
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235 | IO::AIO::munmap $scalar |
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236 | IO::AIO::mremap $scalar, $new_length, $flags[, $new_address] |
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237 | IO::AIO::madvise $scalar, $offset, $length, $advice |
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238 | IO::AIO::mprotect $scalar, $offset, $length, $protect |
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239 | IO::AIO::munlock $scalar, $offset = 0, $length = undef |
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240 | IO::AIO::munlockall |
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241 | |
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242 | # stat extensions |
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243 | $counter = IO::AIO::st_gen |
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244 | $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime |
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245 | ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime |
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246 | $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec |
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247 | $seconds = IO::AIO::st_btimesec |
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248 | ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec |
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249 | |
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250 | # very much unportable syscalls |
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251 | IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags |
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252 | IO::AIO::tee $r_fh, $w_fh, $length, $flags |
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253 | $actual_size = IO::AIO::pipesize $r_fh[, $new_size] |
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254 | ($rfh, $wfh) = IO::AIO::pipe2 [$flags] |
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255 | $fh = IO::AIO::memfd_create $pathname[, $flags] |
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256 | $fh = IO::AIO::eventfd [$initval, [$flags]] |
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257 | $fh = IO::AIO::timerfd_create $clockid[, $flags] |
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258 | ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value |
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259 | ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh |
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260 | |
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261 | API NOTES |
174 | All the "aio_*" calls are more or less thin wrappers around the syscall |
262 | All the "aio_*" calls are more or less thin wrappers around the syscall |
175 | with the same name (sans "aio_"). The arguments are similar or |
263 | with the same name (sans "aio_"). The arguments are similar or |
176 | identical, and they all accept an additional (and optional) $callback |
264 | identical, and they all accept an additional (and optional) $callback |
177 | argument which must be a code reference. This code reference will get |
265 | argument which must be a code reference. This code reference will be |
178 | called with the syscall return code (e.g. most syscalls return -1 on |
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179 | error, unlike perl, which usually delivers "false") as its sole argument |
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180 | after the given syscall has been executed asynchronously. |
266 | called after the syscall has been executed in an asynchronous fashion. |
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267 | The results of the request will be passed as arguments to the callback |
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268 | (and, if an error occured, in $!) - for most requests the syscall return |
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269 | code (e.g. most syscalls return -1 on error, unlike perl, which usually |
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270 | delivers "false"). |
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271 | |
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272 | Some requests (such as "aio_readdir") pass the actual results and |
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273 | communicate failures by passing "undef". |
181 | |
274 | |
182 | All functions expecting a filehandle keep a copy of the filehandle |
275 | All functions expecting a filehandle keep a copy of the filehandle |
183 | internally until the request has finished. |
276 | internally until the request has finished. |
184 | |
277 | |
185 | All functions return request objects of type IO::AIO::REQ that allow |
278 | All functions return request objects of type IO::AIO::REQ that allow |
186 | further manipulation of those requests while they are in-flight. |
279 | further manipulation of those requests while they are in-flight. |
187 | |
280 | |
188 | The pathnames you pass to these routines *must* be absolute and encoded |
281 | The pathnames you pass to these routines *should* be absolute. The |
189 | as octets. The reason for the former is that at the time the request is |
282 | reason for this is that at the time the request is being executed, the |
190 | being executed, the current working directory could have changed. |
283 | current working directory could have changed. Alternatively, you can |
191 | Alternatively, you can make sure that you never change the current |
284 | make sure that you never change the current working directory anywhere |
192 | working directory anywhere in the program and then use relative paths. |
285 | in the program and then use relative paths. You can also take advantage |
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286 | of IO::AIOs working directory abstraction, that lets you specify paths |
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287 | relative to some previously-opened "working directory object" - see the |
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288 | description of the "IO::AIO::WD" class later in this document. |
193 | |
289 | |
194 | To encode pathnames as octets, either make sure you either: a) always |
290 | To encode pathnames as octets, either make sure you either: a) always |
195 | pass in filenames you got from outside (command line, readdir etc.) |
291 | pass in filenames you got from outside (command line, readdir etc.) |
196 | without tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module |
292 | without tinkering, b) are in your native filesystem encoding, c) use the |
197 | and encode your pathnames to the locale (or other) encoding in effect in |
293 | Encode module and encode your pathnames to the locale (or other) |
198 | the user environment, d) use Glib::filename_from_unicode on unicode |
294 | encoding in effect in the user environment, d) use |
199 | filenames or e) use something else to ensure your scalar has the correct |
295 | Glib::filename_from_unicode on unicode filenames or e) use something |
200 | contents. |
296 | else to ensure your scalar has the correct contents. |
201 | |
297 | |
202 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
298 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
203 | handles correctly whether it is set or not. |
299 | handles correctly whether it is set or not. |
204 | |
300 | |
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301 | AIO REQUEST FUNCTIONS |
205 | $prev_pri = aioreq_pri [$pri] |
302 | $prev_pri = aioreq_pri [$pri] |
206 | Returns the priority value that would be used for the next request |
303 | Returns the priority value that would be used for the next request |
207 | and, if $pri is given, sets the priority for the next aio request. |
304 | and, if $pri is given, sets the priority for the next aio request. |
208 | |
305 | |
209 | The default priority is 0, the minimum and maximum priorities are -4 |
306 | The default priority is 0, the minimum and maximum priorities are -4 |
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231 | Similar to "aioreq_pri", but subtracts the given value from the |
328 | Similar to "aioreq_pri", but subtracts the given value from the |
232 | current priority, so the effect is cumulative. |
329 | current priority, so the effect is cumulative. |
233 | |
330 | |
234 | aio_open $pathname, $flags, $mode, $callback->($fh) |
331 | aio_open $pathname, $flags, $mode, $callback->($fh) |
235 | Asynchronously open or create a file and call the callback with a |
332 | Asynchronously open or create a file and call the callback with a |
236 | newly created filehandle for the file. |
333 | newly created filehandle for the file (or "undef" in case of an |
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334 | error). |
237 | |
335 | |
238 | The pathname passed to "aio_open" must be absolute. See API NOTES, |
336 | The pathname passed to "aio_open" must be absolute. See API NOTES, |
239 | above, for an explanation. |
337 | above, for an explanation. |
240 | |
338 | |
241 | The $flags argument is a bitmask. See the "Fcntl" module for a list. |
339 | The $flags argument is a bitmask. See the "Fcntl" module for a list. |
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248 | will be modified by the umask in effect then the request is being |
346 | will be modified by the umask in effect then the request is being |
249 | executed, so better never change the umask. |
347 | executed, so better never change the umask. |
250 | |
348 | |
251 | Example: |
349 | Example: |
252 | |
350 | |
253 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
351 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
254 | if ($_[0]) { |
352 | if ($_[0]) { |
255 | print "open successful, fh is $_[0]\n"; |
353 | print "open successful, fh is $_[0]\n"; |
256 | ... |
354 | ... |
257 | } else { |
355 | } else { |
258 | die "open failed: $!\n"; |
356 | die "open failed: $!\n"; |
259 | } |
357 | } |
260 | }; |
358 | }; |
261 | |
359 | |
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360 | In addition to all the common open modes/flags ("O_RDONLY", |
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361 | "O_WRONLY", "O_RDWR", "O_CREAT", "O_TRUNC", "O_EXCL" and |
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362 | "O_APPEND"), the following POSIX and non-POSIX constants are |
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363 | available (missing ones on your system are, as usual, 0): |
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364 | |
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365 | "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY", |
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366 | "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY", |
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367 | "O_DSYNC", "O_RSYNC", "O_SYNC", "O_PATH", "O_TMPFILE", "O_TTY_INIT" |
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368 | and "O_ACCMODE". |
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369 | |
262 | aio_close $fh, $callback->($status) |
370 | aio_close $fh, $callback->($status) |
263 | Asynchronously close a file and call the callback with the result |
371 | Asynchronously close a file and call the callback with the result |
264 | code. |
372 | code. |
265 | |
373 | |
266 | Unfortunately, you can't do this to perl. Perl *insists* very |
374 | Unfortunately, you can't do this to perl. Perl *insists* very |
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271 | will use dup2 to overwrite the file descriptor with the write-end of |
379 | will use dup2 to overwrite the file descriptor with the write-end of |
272 | a pipe (the pipe fd will be created on demand and will be cached). |
380 | a pipe (the pipe fd will be created on demand and will be cached). |
273 | |
381 | |
274 | Or in other words: the file descriptor will be closed, but it will |
382 | Or in other words: the file descriptor will be closed, but it will |
275 | not be free for reuse until the perl filehandle is closed. |
383 | not be free for reuse until the perl filehandle is closed. |
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384 | |
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385 | aio_seek $fh, $offset, $whence, $callback->($offs) |
|
|
386 | Seeks the filehandle to the new $offset, similarly to perl's |
|
|
387 | "sysseek". The $whence can use the traditional values (0 for |
|
|
388 | "IO::AIO::SEEK_SET", 1 for "IO::AIO::SEEK_CUR" or 2 for |
|
|
389 | "IO::AIO::SEEK_END"). |
|
|
390 | |
|
|
391 | The resulting absolute offset will be passed to the callback, or -1 |
|
|
392 | in case of an error. |
|
|
393 | |
|
|
394 | In theory, the $whence constants could be different than the |
|
|
395 | corresponding values from Fcntl, but perl guarantees they are the |
|
|
396 | same, so don't panic. |
|
|
397 | |
|
|
398 | As a GNU/Linux (and maybe Solaris) extension, also the constants |
|
|
399 | "IO::AIO::SEEK_DATA" and "IO::AIO::SEEK_HOLE" are available, if they |
|
|
400 | could be found. No guarantees about suitability for use in |
|
|
401 | "aio_seek" or Perl's "sysseek" can be made though, although I would |
|
|
402 | naively assume they "just work". |
276 | |
403 | |
277 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
404 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
278 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
405 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
279 | Reads or writes $length bytes from or to the specified $fh and |
406 | Reads or writes $length bytes from or to the specified $fh and |
280 | $offset into the scalar given by $data and offset $dataoffset and |
407 | $offset into the scalar given by $data and offset $dataoffset and |
281 | calls the callback without the actual number of bytes read (or -1 on |
408 | calls the callback with the actual number of bytes transferred (or |
282 | error, just like the syscall). |
409 | -1 on error, just like the syscall). |
283 | |
410 | |
284 | "aio_read" will, like "sysread", shrink or grow the $data scalar to |
411 | "aio_read" will, like "sysread", shrink or grow the $data scalar to |
285 | offset plus the actual number of bytes read. |
412 | offset plus the actual number of bytes read. |
286 | |
413 | |
287 | If $offset is undefined, then the current file descriptor offset |
414 | If $offset is undefined, then the current file descriptor offset |
… | |
… | |
309 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
436 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
310 | Tries to copy $length bytes from $in_fh to $out_fh. It starts |
437 | Tries to copy $length bytes from $in_fh to $out_fh. It starts |
311 | reading at byte offset $in_offset, and starts writing at the current |
438 | reading at byte offset $in_offset, and starts writing at the current |
312 | file offset of $out_fh. Because of that, it is not safe to issue |
439 | file offset of $out_fh. Because of that, it is not safe to issue |
313 | more than one "aio_sendfile" per $out_fh, as they will interfere |
440 | more than one "aio_sendfile" per $out_fh, as they will interfere |
314 | with each other. |
441 | with each other. The same $in_fh works fine though, as this function |
|
|
442 | does not move or use the file offset of $in_fh. |
315 | |
443 | |
|
|
444 | Please note that "aio_sendfile" can read more bytes from $in_fh than |
|
|
445 | are written, and there is no way to find out how many more bytes |
|
|
446 | have been read from "aio_sendfile" alone, as "aio_sendfile" only |
|
|
447 | provides the number of bytes written to $out_fh. Only if the result |
|
|
448 | value equals $length one can assume that $length bytes have been |
|
|
449 | read. |
|
|
450 | |
|
|
451 | Unlike with other "aio_" functions, it makes a lot of sense to use |
|
|
452 | "aio_sendfile" on non-blocking sockets, as long as one end |
|
|
453 | (typically the $in_fh) is a file - the file I/O will then be |
|
|
454 | asynchronous, while the socket I/O will be non-blocking. Note, |
|
|
455 | however, that you can run into a trap where "aio_sendfile" reads |
|
|
456 | some data with readahead, then fails to write all data, and when the |
|
|
457 | socket is ready the next time, the data in the cache is already |
|
|
458 | lost, forcing "aio_sendfile" to again hit the disk. Explicit |
|
|
459 | "aio_read" + "aio_write" let's you better control resource usage. |
|
|
460 | |
316 | This call tries to make use of a native "sendfile" syscall to |
461 | This call tries to make use of a native "sendfile"-like syscall to |
317 | provide zero-copy operation. For this to work, $out_fh should refer |
462 | provide zero-copy operation. For this to work, $out_fh should refer |
318 | to a socket, and $in_fh should refer to mmap'able file. |
463 | to a socket, and $in_fh should refer to an mmap'able file. |
319 | |
464 | |
320 | If the native sendfile call fails or is not implemented, it will be |
465 | If a native sendfile cannot be found or it fails with "ENOSYS", |
321 | emulated, so you can call "aio_sendfile" on any type of filehandle |
466 | "EINVAL", "ENOTSUP", "EOPNOTSUPP", "EAFNOSUPPORT", "EPROTOTYPE" or |
322 | regardless of the limitations of the operating system. |
467 | "ENOTSOCK", it will be emulated, so you can call "aio_sendfile" on |
|
|
468 | any type of filehandle regardless of the limitations of the |
|
|
469 | operating system. |
323 | |
470 | |
324 | Please note, however, that "aio_sendfile" can read more bytes from |
471 | As native sendfile syscalls (as practically any non-POSIX interface |
325 | $in_fh than are written, and there is no way to find out how many |
472 | hacked together in a hurry to improve benchmark numbers) tend to be |
326 | bytes have been read from "aio_sendfile" alone, as "aio_sendfile" |
473 | rather buggy on many systems, this implementation tries to work |
327 | only provides the number of bytes written to $out_fh. Only if the |
474 | around some known bugs in Linux and FreeBSD kernels (probably |
328 | result value equals $length one can assume that $length bytes have |
475 | others, too), but that might fail, so you really really should check |
329 | been read. |
476 | the return value of "aio_sendfile" - fewer bytes than expected might |
|
|
477 | have been transferred. |
330 | |
478 | |
331 | aio_readahead $fh,$offset,$length, $callback->($retval) |
479 | aio_readahead $fh,$offset,$length, $callback->($retval) |
332 | "aio_readahead" populates the page cache with data from a file so |
480 | "aio_readahead" populates the page cache with data from a file so |
333 | that subsequent reads from that file will not block on disk I/O. The |
481 | that subsequent reads from that file will not block on disk I/O. The |
334 | $offset argument specifies the starting point from which data is to |
482 | $offset argument specifies the starting point from which data is to |
… | |
… | |
337 | to a page boundary and bytes are read up to the next page boundary |
485 | to a page boundary and bytes are read up to the next page boundary |
338 | greater than or equal to (off-set+length). "aio_readahead" does not |
486 | greater than or equal to (off-set+length). "aio_readahead" does not |
339 | read beyond the end of the file. The current file offset of the file |
487 | read beyond the end of the file. The current file offset of the file |
340 | is left unchanged. |
488 | is left unchanged. |
341 | |
489 | |
342 | If that syscall doesn't exist (likely if your OS isn't Linux) it |
490 | If that syscall doesn't exist (likely if your kernel isn't Linux) it |
343 | will be emulated by simply reading the data, which would have a |
491 | will be emulated by simply reading the data, which would have a |
344 | similar effect. |
492 | similar effect. |
345 | |
493 | |
346 | aio_stat $fh_or_path, $callback->($status) |
494 | aio_stat $fh_or_path, $callback->($status) |
347 | aio_lstat $fh, $callback->($status) |
495 | aio_lstat $fh, $callback->($status) |
348 | Works like perl's "stat" or "lstat" in void context. The callback |
496 | Works almost exactly like perl's "stat" or "lstat" in void context. |
349 | will be called after the stat and the results will be available |
497 | The callback will be called after the stat and the results will be |
350 | using "stat _" or "-s _" etc... |
498 | available using "stat _" or "-s _" and other tests (with the |
|
|
499 | exception of "-B" and "-T"). |
351 | |
500 | |
352 | The pathname passed to "aio_stat" must be absolute. See API NOTES, |
501 | The pathname passed to "aio_stat" must be absolute. See API NOTES, |
353 | above, for an explanation. |
502 | above, for an explanation. |
354 | |
503 | |
355 | Currently, the stats are always 64-bit-stats, i.e. instead of |
504 | Currently, the stats are always 64-bit-stats, i.e. instead of |
356 | returning an error when stat'ing a large file, the results will be |
505 | returning an error when stat'ing a large file, the results will be |
357 | silently truncated unless perl itself is compiled with large file |
506 | silently truncated unless perl itself is compiled with large file |
358 | support. |
507 | support. |
359 | |
508 | |
|
|
509 | To help interpret the mode and dev/rdev stat values, IO::AIO offers |
|
|
510 | the following constants and functions (if not implemented, the |
|
|
511 | constants will be 0 and the functions will either "croak" or fall |
|
|
512 | back on traditional behaviour). |
|
|
513 | |
|
|
514 | "S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG", |
|
|
515 | "S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t", |
|
|
516 | "IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor". |
|
|
517 | |
|
|
518 | To access higher resolution stat timestamps, see "SUBSECOND STAT |
|
|
519 | TIME ACCESS". |
|
|
520 | |
360 | Example: Print the length of /etc/passwd: |
521 | Example: Print the length of /etc/passwd: |
361 | |
522 | |
362 | aio_stat "/etc/passwd", sub { |
523 | aio_stat "/etc/passwd", sub { |
363 | $_[0] and die "stat failed: $!"; |
524 | $_[0] and die "stat failed: $!"; |
364 | print "size is ", -s _, "\n"; |
525 | print "size is ", -s _, "\n"; |
365 | }; |
526 | }; |
366 | |
527 | |
|
|
528 | aio_statvfs $fh_or_path, $callback->($statvfs) |
|
|
529 | Works like the POSIX "statvfs" or "fstatvfs" syscalls, depending on |
|
|
530 | whether a file handle or path was passed. |
|
|
531 | |
|
|
532 | On success, the callback is passed a hash reference with the |
|
|
533 | following members: "bsize", "frsize", "blocks", "bfree", "bavail", |
|
|
534 | "files", "ffree", "favail", "fsid", "flag" and "namemax". On |
|
|
535 | failure, "undef" is passed. |
|
|
536 | |
|
|
537 | The following POSIX IO::AIO::ST_* constants are defined: "ST_RDONLY" |
|
|
538 | and "ST_NOSUID". |
|
|
539 | |
|
|
540 | The following non-POSIX IO::AIO::ST_* flag masks are defined to |
|
|
541 | their correct value when available, or to 0 on systems that do not |
|
|
542 | support them: "ST_NODEV", "ST_NOEXEC", "ST_SYNCHRONOUS", |
|
|
543 | "ST_MANDLOCK", "ST_WRITE", "ST_APPEND", "ST_IMMUTABLE", |
|
|
544 | "ST_NOATIME", "ST_NODIRATIME" and "ST_RELATIME". |
|
|
545 | |
|
|
546 | Example: stat "/wd" and dump out the data if successful. |
|
|
547 | |
|
|
548 | aio_statvfs "/wd", sub { |
|
|
549 | my $f = $_[0] |
|
|
550 | or die "statvfs: $!"; |
|
|
551 | |
|
|
552 | use Data::Dumper; |
|
|
553 | say Dumper $f; |
|
|
554 | }; |
|
|
555 | |
|
|
556 | # result: |
|
|
557 | { |
|
|
558 | bsize => 1024, |
|
|
559 | bfree => 4333064312, |
|
|
560 | blocks => 10253828096, |
|
|
561 | files => 2050765568, |
|
|
562 | flag => 4096, |
|
|
563 | favail => 2042092649, |
|
|
564 | bavail => 4333064312, |
|
|
565 | ffree => 2042092649, |
|
|
566 | namemax => 255, |
|
|
567 | frsize => 1024, |
|
|
568 | fsid => 1810 |
|
|
569 | } |
|
|
570 | |
367 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
571 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
368 | Works like perl's "utime" function (including the special case of |
572 | Works like perl's "utime" function (including the special case of |
369 | $atime and $mtime being undef). Fractional times are supported if |
573 | $atime and $mtime being undef). Fractional times are supported if |
370 | the underlying syscalls support them. |
574 | the underlying syscalls support them. |
371 | |
575 | |
372 | When called with a pathname, uses utimes(2) if available, otherwise |
576 | When called with a pathname, uses utimensat(2) or utimes(2) if |
373 | utime(2). If called on a file descriptor, uses futimes(2) if |
577 | available, otherwise utime(2). If called on a file descriptor, uses |
374 | available, otherwise returns ENOSYS, so this is not portable. |
578 | futimens(2) or futimes(2) if available, otherwise returns ENOSYS, so |
|
|
579 | this is not portable. |
375 | |
580 | |
376 | Examples: |
581 | Examples: |
377 | |
582 | |
378 | # set atime and mtime to current time (basically touch(1)): |
583 | # set atime and mtime to current time (basically touch(1)): |
379 | aio_utime "path", undef, undef; |
584 | aio_utime "path", undef, undef; |
… | |
… | |
393 | aio_chown "path", 0, undef; |
598 | aio_chown "path", 0, undef; |
394 | |
599 | |
395 | aio_truncate $fh_or_path, $offset, $callback->($status) |
600 | aio_truncate $fh_or_path, $offset, $callback->($status) |
396 | Works like truncate(2) or ftruncate(2). |
601 | Works like truncate(2) or ftruncate(2). |
397 | |
602 | |
|
|
603 | aio_allocate $fh, $mode, $offset, $len, $callback->($status) |
|
|
604 | Allocates or frees disk space according to the $mode argument. See |
|
|
605 | the linux "fallocate" documentation for details. |
|
|
606 | |
|
|
607 | $mode is usually 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to allocate |
|
|
608 | space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE | |
|
|
609 | IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range. |
|
|
610 | |
|
|
611 | IO::AIO also supports "FALLOC_FL_COLLAPSE_RANGE", to remove a range |
|
|
612 | (without leaving a hole), "FALLOC_FL_ZERO_RANGE", to zero a range, |
|
|
613 | "FALLOC_FL_INSERT_RANGE" to insert a range and |
|
|
614 | "FALLOC_FL_UNSHARE_RANGE" to unshare shared blocks (see your |
|
|
615 | fallocate(2) manpage). |
|
|
616 | |
|
|
617 | The file system block size used by "fallocate" is presumably the |
|
|
618 | "f_bsize" returned by "statvfs", but different filesystems and |
|
|
619 | filetypes can dictate other limitations. |
|
|
620 | |
|
|
621 | If "fallocate" isn't available or cannot be emulated (currently no |
|
|
622 | emulation will be attempted), passes -1 and sets $! to "ENOSYS". |
|
|
623 | |
398 | aio_chmod $fh_or_path, $mode, $callback->($status) |
624 | aio_chmod $fh_or_path, $mode, $callback->($status) |
399 | Works like perl's "chmod" function. |
625 | Works like perl's "chmod" function. |
400 | |
626 | |
401 | aio_unlink $pathname, $callback->($status) |
627 | aio_unlink $pathname, $callback->($status) |
402 | Asynchronously unlink (delete) a file and call the callback with the |
628 | Asynchronously unlink (delete) a file and call the callback with the |
403 | result code. |
629 | result code. |
404 | |
630 | |
405 | aio_mknod $path, $mode, $dev, $callback->($status) |
631 | aio_mknod $pathname, $mode, $dev, $callback->($status) |
406 | [EXPERIMENTAL] |
632 | [EXPERIMENTAL] |
407 | |
633 | |
408 | Asynchronously create a device node (or fifo). See mknod(2). |
634 | Asynchronously create a device node (or fifo). See mknod(2). |
409 | |
635 | |
410 | The only (POSIX-) portable way of calling this function is: |
636 | The only (POSIX-) portable way of calling this function is: |
411 | |
637 | |
412 | aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
638 | aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
|
|
639 | |
|
|
640 | See "aio_stat" for info about some potentially helpful extra |
|
|
641 | constants and functions. |
413 | |
642 | |
414 | aio_link $srcpath, $dstpath, $callback->($status) |
643 | aio_link $srcpath, $dstpath, $callback->($status) |
415 | Asynchronously create a new link to the existing object at $srcpath |
644 | Asynchronously create a new link to the existing object at $srcpath |
416 | at the path $dstpath and call the callback with the result code. |
645 | at the path $dstpath and call the callback with the result code. |
417 | |
646 | |
418 | aio_symlink $srcpath, $dstpath, $callback->($status) |
647 | aio_symlink $srcpath, $dstpath, $callback->($status) |
419 | Asynchronously create a new symbolic link to the existing object at |
648 | Asynchronously create a new symbolic link to the existing object at |
420 | $srcpath at the path $dstpath and call the callback with the result |
649 | $srcpath at the path $dstpath and call the callback with the result |
421 | code. |
650 | code. |
422 | |
651 | |
423 | aio_readlink $path, $callback->($link) |
652 | aio_readlink $pathname, $callback->($link) |
424 | Asynchronously read the symlink specified by $path and pass it to |
653 | Asynchronously read the symlink specified by $path and pass it to |
425 | the callback. If an error occurs, nothing or undef gets passed to |
654 | the callback. If an error occurs, nothing or undef gets passed to |
426 | the callback. |
655 | the callback. |
427 | |
656 | |
|
|
657 | aio_realpath $pathname, $callback->($path) |
|
|
658 | Asynchronously make the path absolute and resolve any symlinks in |
|
|
659 | $path. The resulting path only consists of directories (same as |
|
|
660 | Cwd::realpath). |
|
|
661 | |
|
|
662 | This request can be used to get the absolute path of the current |
|
|
663 | working directory by passing it a path of . (a single dot). |
|
|
664 | |
428 | aio_rename $srcpath, $dstpath, $callback->($status) |
665 | aio_rename $srcpath, $dstpath, $callback->($status) |
429 | Asynchronously rename the object at $srcpath to $dstpath, just as |
666 | Asynchronously rename the object at $srcpath to $dstpath, just as |
430 | rename(2) and call the callback with the result code. |
667 | rename(2) and call the callback with the result code. |
|
|
668 | |
|
|
669 | On systems that support the AIO::WD working directory abstraction |
|
|
670 | natively, the case "[$wd, "."]" as $srcpath is specialcased - |
|
|
671 | instead of failing, "rename" is called on the absolute path of $wd. |
|
|
672 | |
|
|
673 | aio_rename2 $srcpath, $dstpath, $flags, $callback->($status) |
|
|
674 | Basically a version of "aio_rename" with an additional $flags |
|
|
675 | argument. Calling this with "$flags=0" is the same as calling |
|
|
676 | "aio_rename". |
|
|
677 | |
|
|
678 | Non-zero flags are currently only supported on GNU/Linux systems |
|
|
679 | that support renameat2. Other systems fail with "ENOSYS" in this |
|
|
680 | case. |
|
|
681 | |
|
|
682 | The following constants are available (missing ones are, as usual |
|
|
683 | 0), see renameat2(2) for details: |
|
|
684 | |
|
|
685 | "IO::AIO::RENAME_NOREPLACE", "IO::AIO::RENAME_EXCHANGE" and |
|
|
686 | "IO::AIO::RENAME_WHITEOUT". |
431 | |
687 | |
432 | aio_mkdir $pathname, $mode, $callback->($status) |
688 | aio_mkdir $pathname, $mode, $callback->($status) |
433 | Asynchronously mkdir (create) a directory and call the callback with |
689 | Asynchronously mkdir (create) a directory and call the callback with |
434 | the result code. $mode will be modified by the umask at the time the |
690 | the result code. $mode will be modified by the umask at the time the |
435 | request is executed, so do not change your umask. |
691 | request is executed, so do not change your umask. |
436 | |
692 | |
437 | aio_rmdir $pathname, $callback->($status) |
693 | aio_rmdir $pathname, $callback->($status) |
438 | Asynchronously rmdir (delete) a directory and call the callback with |
694 | Asynchronously rmdir (delete) a directory and call the callback with |
439 | the result code. |
695 | the result code. |
440 | |
696 | |
|
|
697 | On systems that support the AIO::WD working directory abstraction |
|
|
698 | natively, the case "[$wd, "."]" is specialcased - instead of |
|
|
699 | failing, "rmdir" is called on the absolute path of $wd. |
|
|
700 | |
441 | aio_readdir $pathname, $callback->($entries) |
701 | aio_readdir $pathname, $callback->($entries) |
442 | Unlike the POSIX call of the same name, "aio_readdir" reads an |
702 | Unlike the POSIX call of the same name, "aio_readdir" reads an |
443 | entire directory (i.e. opendir + readdir + closedir). The entries |
703 | entire directory (i.e. opendir + readdir + closedir). The entries |
444 | will not be sorted, and will NOT include the "." and ".." entries. |
704 | will not be sorted, and will NOT include the "." and ".." entries. |
445 | |
705 | |
446 | The callback is passed a single argument which is either "undef" or |
706 | The callback is passed a single argument which is either "undef" or |
447 | an array-ref with the filenames. |
707 | an array-ref with the filenames. |
448 | |
708 | |
449 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
709 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
450 | Quite similar to "aio_readdir", but the $flags argument allows to |
710 | Quite similar to "aio_readdir", but the $flags argument allows one |
451 | tune behaviour and output format. In case of an error, $entries will |
711 | to tune behaviour and output format. In case of an error, $entries |
452 | be "undef". |
712 | will be "undef". |
453 | |
713 | |
454 | The flags are a combination of the following constants, ORed |
714 | The flags are a combination of the following constants, ORed |
455 | together (the flags will also be passed to the callback, possibly |
715 | together (the flags will also be passed to the callback, possibly |
456 | modified): |
716 | modified): |
457 | |
717 | |
458 | IO::AIO::READDIR_DENTS |
718 | IO::AIO::READDIR_DENTS |
459 | When this flag is off, then the callback gets an arrayref with |
719 | Normally the callback gets an arrayref consisting of names only |
460 | of names only (as with "aio_readdir"), otherwise it gets an |
720 | (as with "aio_readdir"). If this flag is set, then the callback |
461 | arrayref with "[$name, $type, $inode]" arrayrefs, each |
721 | gets an arrayref with "[$name, $type, $inode]" arrayrefs, each |
462 | describing a single directory entry in more detail. |
722 | describing a single directory entry in more detail: |
463 | |
723 | |
464 | $name is the name of the entry. |
724 | $name is the name of the entry. |
465 | |
725 | |
466 | $type is one of the "IO::AIO::DT_xxx" constants: |
726 | $type is one of the "IO::AIO::DT_xxx" constants: |
467 | |
727 | |
468 | "IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR", |
728 | "IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR", |
469 | "IO::AIO::DT_DIR", "IO::AIO::DT_BLK", "IO::AIO::DT_REG", |
729 | "IO::AIO::DT_DIR", "IO::AIO::DT_BLK", "IO::AIO::DT_REG", |
470 | "IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT". |
730 | "IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT". |
471 | |
731 | |
472 | "IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If |
732 | "IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If |
473 | you need to know, you have to run stat yourself. Also, for speed |
733 | you need to know, you have to run stat yourself. Also, for |
474 | reasons, the $type scalars are read-only: you can not modify |
734 | speed/memory reasons, the $type scalars are read-only: you must |
475 | them. |
735 | not modify them. |
476 | |
736 | |
477 | $inode is the inode number (which might not be exact on systems |
737 | $inode is the inode number (which might not be exact on systems |
478 | with 64 bit inode numbers and 32 bit perls). This field has |
738 | with 64 bit inode numbers and 32 bit perls). This field has |
479 | unspecified content on systems that do not deliver the inode |
739 | unspecified content on systems that do not deliver the inode |
480 | information. |
740 | information. |
481 | |
741 | |
482 | IO::AIO::READDIR_DIRS_FIRST |
742 | IO::AIO::READDIR_DIRS_FIRST |
483 | When this flag is set, then the names will be returned in an |
743 | When this flag is set, then the names will be returned in an |
484 | order where likely directories come first. This is useful when |
744 | order where likely directories come first, in optimal stat |
485 | you need to quickly find directories, or you want to find all |
745 | order. This is useful when you need to quickly find directories, |
486 | directories while avoiding to stat() each entry. |
746 | or you want to find all directories while avoiding to stat() |
|
|
747 | each entry. |
487 | |
748 | |
488 | If the system returns type information in readdir, then this is |
749 | If the system returns type information in readdir, then this is |
489 | used to find directories directly. Otherwise, likely directories |
750 | used to find directories directly. Otherwise, likely directories |
490 | are files beginning with ".", or otherwise files with no dots, |
751 | are names beginning with ".", or otherwise names with no dots, |
491 | of which files with short names are tried first. |
752 | of which names with short names are tried first. |
492 | |
753 | |
493 | IO::AIO::READDIR_STAT_ORDER |
754 | IO::AIO::READDIR_STAT_ORDER |
494 | When this flag is set, then the names will be returned in an |
755 | When this flag is set, then the names will be returned in an |
495 | order suitable for stat()'ing each one. That is, when you plan |
756 | order suitable for stat()'ing each one. That is, when you plan |
496 | to stat() all files in the given directory, then the returned |
757 | to stat() most or all files in the given directory, then the |
497 | order will likely be fastest. |
758 | returned order will likely be faster. |
498 | |
759 | |
499 | If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are |
760 | If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are |
500 | specified, then the likely dirs come first, resulting in a less |
761 | specified, then the likely dirs come first, resulting in a less |
501 | optimal stat order. |
762 | optimal stat order for stat'ing all entries, but likely a more |
|
|
763 | optimal order for finding subdirectories. |
502 | |
764 | |
503 | IO::AIO::READDIR_FOUND_UNKNOWN |
765 | IO::AIO::READDIR_FOUND_UNKNOWN |
504 | This flag should not be set when calling "aio_readdirx". |
766 | This flag should not be set when calling "aio_readdirx". |
505 | Instead, it is being set by "aio_readdirx", when any of the |
767 | Instead, it is being set by "aio_readdirx", when any of the |
506 | $type's found were "IO::AIO::DT_UNKNOWN". The absense of this |
768 | $type's found were "IO::AIO::DT_UNKNOWN". The absence of this |
507 | flag therefore indicates that all $type's are known, which can |
769 | flag therefore indicates that all $type's are known, which can |
508 | be used to speed up some algorithms. |
770 | be used to speed up some algorithms. |
509 | |
771 | |
|
|
772 | aio_slurp $pathname, $offset, $length, $data, $callback->($status) |
|
|
773 | Opens, reads and closes the given file. The data is put into $data, |
|
|
774 | which is resized as required. |
|
|
775 | |
|
|
776 | If $offset is negative, then it is counted from the end of the file. |
|
|
777 | |
|
|
778 | If $length is zero, then the remaining length of the file is used. |
|
|
779 | Also, in this case, the same limitations to modifying $data apply as |
|
|
780 | when IO::AIO::mmap is used, i.e. it must only be modified in-place |
|
|
781 | with "substr". If the size of the file is known, specifying a |
|
|
782 | non-zero $length results in a performance advantage. |
|
|
783 | |
|
|
784 | This request is similar to the older "aio_load" request, but since |
|
|
785 | it is a single request, it might be more efficient to use. |
|
|
786 | |
|
|
787 | Example: load /etc/passwd into $passwd. |
|
|
788 | |
|
|
789 | my $passwd; |
|
|
790 | aio_slurp "/etc/passwd", 0, 0, $passwd, sub { |
|
|
791 | $_[0] >= 0 |
|
|
792 | or die "/etc/passwd: $!\n"; |
|
|
793 | |
|
|
794 | printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd; |
|
|
795 | print $passwd; |
|
|
796 | }; |
|
|
797 | IO::AIO::flush; |
|
|
798 | |
510 | aio_load $path, $data, $callback->($status) |
799 | aio_load $pathname, $data, $callback->($status) |
511 | This is a composite request that tries to fully load the given file |
800 | This is a composite request that tries to fully load the given file |
512 | into memory. Status is the same as with aio_read. |
801 | into memory. Status is the same as with aio_read. |
|
|
802 | |
|
|
803 | Using "aio_slurp" might be more efficient, as it is a single |
|
|
804 | request. |
513 | |
805 | |
514 | aio_copy $srcpath, $dstpath, $callback->($status) |
806 | aio_copy $srcpath, $dstpath, $callback->($status) |
515 | Try to copy the *file* (directories not supported as either source |
807 | Try to copy the *file* (directories not supported as either source |
516 | or destination) from $srcpath to $dstpath and call the callback with |
808 | or destination) from $srcpath to $dstpath and call the callback with |
517 | the 0 (error) or -1 ok. |
809 | a status of 0 (ok) or -1 (error, see $!). |
|
|
810 | |
|
|
811 | Existing destination files will be truncated. |
518 | |
812 | |
519 | This is a composite request that creates the destination file with |
813 | This is a composite request that creates the destination file with |
520 | mode 0200 and copies the contents of the source file into it using |
814 | mode 0200 and copies the contents of the source file into it using |
521 | "aio_sendfile", followed by restoring atime, mtime, access mode and |
815 | "aio_sendfile", followed by restoring atime, mtime, access mode and |
522 | uid/gid, in that order. |
816 | uid/gid, in that order. |
… | |
… | |
526 | uid/gid, where errors are being ignored. |
820 | uid/gid, where errors are being ignored. |
527 | |
821 | |
528 | aio_move $srcpath, $dstpath, $callback->($status) |
822 | aio_move $srcpath, $dstpath, $callback->($status) |
529 | Try to move the *file* (directories not supported as either source |
823 | Try to move the *file* (directories not supported as either source |
530 | or destination) from $srcpath to $dstpath and call the callback with |
824 | or destination) from $srcpath to $dstpath and call the callback with |
531 | the 0 (error) or -1 ok. |
825 | a status of 0 (ok) or -1 (error, see $!). |
532 | |
826 | |
533 | This is a composite request that tries to rename(2) the file first; |
827 | This is a composite request that tries to rename(2) the file first; |
534 | if rename fails with "EXDEV", it copies the file with "aio_copy" |
828 | if rename fails with "EXDEV", it copies the file with "aio_copy" |
535 | and, if that is successful, unlinks the $srcpath. |
829 | and, if that is successful, unlinks the $srcpath. |
536 | |
830 | |
537 | aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
831 | aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) |
538 | Scans a directory (similar to "aio_readdir") but additionally tries |
832 | Scans a directory (similar to "aio_readdir") but additionally tries |
539 | to efficiently separate the entries of directory $path into two sets |
833 | to efficiently separate the entries of directory $path into two sets |
540 | of names, directories you can recurse into (directories), and ones |
834 | of names, directories you can recurse into (directories), and ones |
541 | you cannot recurse into (everything else, including symlinks to |
835 | you cannot recurse into (everything else, including symlinks to |
542 | directories). |
836 | directories). |
543 | |
837 | |
544 | "aio_scandir" is a composite request that creates of many sub |
838 | "aio_scandir" is a composite request that generates many sub |
545 | requests_ $maxreq specifies the maximum number of outstanding aio |
839 | requests. $maxreq specifies the maximum number of outstanding aio |
546 | requests that this function generates. If it is "<= 0", then a |
840 | requests that this function generates. If it is "<= 0", then a |
547 | suitable default will be chosen (currently 4). |
841 | suitable default will be chosen (currently 4). |
548 | |
842 | |
549 | On error, the callback is called without arguments, otherwise it |
843 | On error, the callback is called without arguments, otherwise it |
550 | receives two array-refs with path-relative entry names. |
844 | receives two array-refs with path-relative entry names. |
… | |
… | |
575 | Then entries will be sorted into likely directories a non-initial |
869 | Then entries will be sorted into likely directories a non-initial |
576 | dot currently) and likely non-directories (see "aio_readdirx"). Then |
870 | dot currently) and likely non-directories (see "aio_readdirx"). Then |
577 | every entry plus an appended "/." will be "stat"'ed, likely |
871 | every entry plus an appended "/." will be "stat"'ed, likely |
578 | directories first, in order of their inode numbers. If that |
872 | directories first, in order of their inode numbers. If that |
579 | succeeds, it assumes that the entry is a directory or a symlink to |
873 | succeeds, it assumes that the entry is a directory or a symlink to |
580 | directory (which will be checked seperately). This is often faster |
874 | directory (which will be checked separately). This is often faster |
581 | than stat'ing the entry itself because filesystems might detect the |
875 | than stat'ing the entry itself because filesystems might detect the |
582 | type of the entry without reading the inode data (e.g. ext2fs |
876 | type of the entry without reading the inode data (e.g. ext2fs |
583 | filetype feature), even on systems that cannot return the filetype |
877 | filetype feature), even on systems that cannot return the filetype |
584 | information on readdir. |
878 | information on readdir. |
585 | |
879 | |
… | |
… | |
591 | |
885 | |
592 | It will also likely work on non-POSIX filesystems with reduced |
886 | It will also likely work on non-POSIX filesystems with reduced |
593 | efficiency as those tend to return 0 or 1 as link counts, which |
887 | efficiency as those tend to return 0 or 1 as link counts, which |
594 | disables the directory counting heuristic. |
888 | disables the directory counting heuristic. |
595 | |
889 | |
596 | aio_rmtree $path, $callback->($status) |
890 | aio_rmtree $pathname, $callback->($status) |
597 | Delete a directory tree starting (and including) $path, return the |
891 | Delete a directory tree starting (and including) $path, return the |
598 | status of the final "rmdir" only. This is a composite request that |
892 | status of the final "rmdir" only. This is a composite request that |
599 | uses "aio_scandir" to recurse into and rmdir directories, and unlink |
893 | uses "aio_scandir" to recurse into and rmdir directories, and unlink |
600 | everything else. |
894 | everything else. |
601 | |
895 | |
|
|
896 | aio_fcntl $fh, $cmd, $arg, $callback->($status) |
|
|
897 | aio_ioctl $fh, $request, $buf, $callback->($status) |
|
|
898 | These work just like the "fcntl" and "ioctl" built-in functions, |
|
|
899 | except they execute asynchronously and pass the return value to the |
|
|
900 | callback. |
|
|
901 | |
|
|
902 | Both calls can be used for a lot of things, some of which make more |
|
|
903 | sense to run asynchronously in their own thread, while some others |
|
|
904 | make less sense. For example, calls that block waiting for external |
|
|
905 | events, such as locking, will also lock down an I/O thread while it |
|
|
906 | is waiting, which can deadlock the whole I/O system. At the same |
|
|
907 | time, there might be no alternative to using a thread to wait. |
|
|
908 | |
|
|
909 | So in general, you should only use these calls for things that do |
|
|
910 | (filesystem) I/O, not for things that wait for other events |
|
|
911 | (network, other processes), although if you are careful and know |
|
|
912 | what you are doing, you still can. |
|
|
913 | |
|
|
914 | The following constants are available (missing ones are, as usual |
|
|
915 | 0): |
|
|
916 | |
|
|
917 | "F_DUPFD_CLOEXEC", |
|
|
918 | |
|
|
919 | "F_OFD_GETLK", "F_OFD_SETLK", "F_OFD_GETLKW", |
|
|
920 | |
|
|
921 | "FIFREEZE", "FITHAW", "FITRIM", "FICLONE", "FICLONERANGE", |
|
|
922 | "FIDEDUPERANGE". |
|
|
923 | |
|
|
924 | "FS_IOC_GETFLAGS", "FS_IOC_SETFLAGS", "FS_IOC_GETVERSION", |
|
|
925 | "FS_IOC_SETVERSION", "FS_IOC_FIEMAP". |
|
|
926 | |
|
|
927 | "FS_IOC_FSGETXATTR", "FS_IOC_FSSETXATTR", |
|
|
928 | "FS_IOC_SET_ENCRYPTION_POLICY", "FS_IOC_GET_ENCRYPTION_PWSALT", |
|
|
929 | "FS_IOC_GET_ENCRYPTION_POLICY", "FS_KEY_DESCRIPTOR_SIZE". |
|
|
930 | |
|
|
931 | "FS_SECRM_FL", "FS_UNRM_FL", "FS_COMPR_FL", "FS_SYNC_FL", |
|
|
932 | "FS_IMMUTABLE_FL", "FS_APPEND_FL", "FS_NODUMP_FL", "FS_NOATIME_FL", |
|
|
933 | "FS_DIRTY_FL", "FS_COMPRBLK_FL", "FS_NOCOMP_FL", "FS_ENCRYPT_FL", |
|
|
934 | "FS_BTREE_FL", "FS_INDEX_FL", "FS_JOURNAL_DATA_FL", "FS_NOTAIL_FL", |
|
|
935 | "FS_DIRSYNC_FL", "FS_TOPDIR_FL", "FS_FL_USER_MODIFIABLE". |
|
|
936 | |
|
|
937 | "FS_XFLAG_REALTIME", "FS_XFLAG_PREALLOC", "FS_XFLAG_IMMUTABLE", |
|
|
938 | "FS_XFLAG_APPEND", "FS_XFLAG_SYNC", "FS_XFLAG_NOATIME", |
|
|
939 | "FS_XFLAG_NODUMP", "FS_XFLAG_RTINHERIT", "FS_XFLAG_PROJINHERIT", |
|
|
940 | "FS_XFLAG_NOSYMLINKS", "FS_XFLAG_EXTSIZE", "FS_XFLAG_EXTSZINHERIT", |
|
|
941 | "FS_XFLAG_NODEFRAG", "FS_XFLAG_FILESTREAM", "FS_XFLAG_DAX", |
|
|
942 | "FS_XFLAG_HASATTR", |
|
|
943 | |
602 | aio_sync $callback->($status) |
944 | aio_sync $callback->($status) |
603 | Asynchronously call sync and call the callback when finished. |
945 | Asynchronously call sync and call the callback when finished. |
604 | |
946 | |
605 | aio_fsync $fh, $callback->($status) |
947 | aio_fsync $fh, $callback->($status) |
606 | Asynchronously call fsync on the given filehandle and call the |
948 | Asynchronously call fsync on the given filehandle and call the |
… | |
… | |
610 | Asynchronously call fdatasync on the given filehandle and call the |
952 | Asynchronously call fdatasync on the given filehandle and call the |
611 | callback with the fdatasync result code. |
953 | callback with the fdatasync result code. |
612 | |
954 | |
613 | If this call isn't available because your OS lacks it or it couldn't |
955 | If this call isn't available because your OS lacks it or it couldn't |
614 | be detected, it will be emulated by calling "fsync" instead. |
956 | be detected, it will be emulated by calling "fsync" instead. |
|
|
957 | |
|
|
958 | aio_syncfs $fh, $callback->($status) |
|
|
959 | Asynchronously call the syncfs syscall to sync the filesystem |
|
|
960 | associated to the given filehandle and call the callback with the |
|
|
961 | syncfs result code. If syncfs is not available, calls sync(), but |
|
|
962 | returns -1 and sets errno to "ENOSYS" nevertheless. |
615 | |
963 | |
616 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
964 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
617 | Sync the data portion of the file specified by $offset and $length |
965 | Sync the data portion of the file specified by $offset and $length |
618 | to disk (but NOT the metadata), by calling the Linux-specific |
966 | to disk (but NOT the metadata), by calling the Linux-specific |
619 | sync_file_range call. If sync_file_range is not available or it |
967 | sync_file_range call. If sync_file_range is not available or it |
… | |
… | |
623 | "IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE", |
971 | "IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE", |
624 | "IO::AIO::SYNC_FILE_RANGE_WRITE" and |
972 | "IO::AIO::SYNC_FILE_RANGE_WRITE" and |
625 | "IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER": refer to the sync_file_range |
973 | "IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER": refer to the sync_file_range |
626 | manpage for details. |
974 | manpage for details. |
627 | |
975 | |
628 | aio_pathsync $path, $callback->($status) |
976 | aio_pathsync $pathname, $callback->($status) |
629 | This request tries to open, fsync and close the given path. This is |
977 | This request tries to open, fsync and close the given path. This is |
630 | a composite request intended to sync directories after directory |
978 | a composite request intended to sync directories after directory |
631 | operations (E.g. rename). This might not work on all operating |
979 | operations (E.g. rename). This might not work on all operating |
632 | systems or have any specific effect, but usually it makes sure that |
980 | systems or have any specific effect, but usually it makes sure that |
633 | directory changes get written to disc. It works for anything that |
981 | directory changes get written to disc. It works for anything that |
… | |
… | |
636 | Future versions of this function might fall back to other methods |
984 | Future versions of this function might fall back to other methods |
637 | when "fsync" on the directory fails (such as calling "sync"). |
985 | when "fsync" on the directory fails (such as calling "sync"). |
638 | |
986 | |
639 | Passes 0 when everything went ok, and -1 on error. |
987 | Passes 0 when everything went ok, and -1 on error. |
640 | |
988 | |
|
|
989 | aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, |
|
|
990 | $callback->($status) |
|
|
991 | This is a rather advanced IO::AIO call, which only works on |
|
|
992 | mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it |
|
|
993 | also works on data scalars managed by the Sys::Mmap or Mmap modules, |
|
|
994 | note that the scalar must only be modified in-place while an aio |
|
|
995 | operation is pending on it). |
|
|
996 | |
|
|
997 | It calls the "msync" function of your OS, if available, with the |
|
|
998 | memory area starting at $offset in the string and ending $length |
|
|
999 | bytes later. If $length is negative, counts from the end, and if |
|
|
1000 | $length is "undef", then it goes till the end of the string. The |
|
|
1001 | flags can be either "IO::AIO::MS_ASYNC" or "IO::AIO::MS_SYNC", plus |
|
|
1002 | an optional "IO::AIO::MS_INVALIDATE". |
|
|
1003 | |
|
|
1004 | aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, |
|
|
1005 | $callback->($status) |
|
|
1006 | This is a rather advanced IO::AIO call, which works best on |
|
|
1007 | mmap(2)ed scalars. |
|
|
1008 | |
|
|
1009 | It touches (reads or writes) all memory pages in the specified range |
|
|
1010 | inside the scalar. All caveats and parameters are the same as for |
|
|
1011 | "aio_msync", above, except for flags, which must be either 0 (which |
|
|
1012 | reads all pages and ensures they are instantiated) or |
|
|
1013 | "IO::AIO::MT_MODIFY", which modifies the memory pages (by reading |
|
|
1014 | and writing an octet from it, which dirties the page). |
|
|
1015 | |
|
|
1016 | aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
|
|
1017 | This is a rather advanced IO::AIO call, which works best on |
|
|
1018 | mmap(2)ed scalars. |
|
|
1019 | |
|
|
1020 | It reads in all the pages of the underlying storage into memory (if |
|
|
1021 | any) and locks them, so they are not getting swapped/paged out or |
|
|
1022 | removed. |
|
|
1023 | |
|
|
1024 | If $length is undefined, then the scalar will be locked till the |
|
|
1025 | end. |
|
|
1026 | |
|
|
1027 | On systems that do not implement "mlock", this function returns -1 |
|
|
1028 | and sets errno to "ENOSYS". |
|
|
1029 | |
|
|
1030 | Note that the corresponding "munlock" is synchronous and is |
|
|
1031 | documented under "MISCELLANEOUS FUNCTIONS". |
|
|
1032 | |
|
|
1033 | Example: open a file, mmap and mlock it - both will be undone when |
|
|
1034 | $data gets destroyed. |
|
|
1035 | |
|
|
1036 | open my $fh, "<", $path or die "$path: $!"; |
|
|
1037 | my $data; |
|
|
1038 | IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; |
|
|
1039 | aio_mlock $data; # mlock in background |
|
|
1040 | |
|
|
1041 | aio_mlockall $flags, $callback->($status) |
|
|
1042 | Calls the "mlockall" function with the given $flags (a combination |
|
|
1043 | of "IO::AIO::MCL_CURRENT", "IO::AIO::MCL_FUTURE" and |
|
|
1044 | "IO::AIO::MCL_ONFAULT"). |
|
|
1045 | |
|
|
1046 | On systems that do not implement "mlockall", this function returns |
|
|
1047 | -1 and sets errno to "ENOSYS". Similarly, flag combinations not |
|
|
1048 | supported by the system result in a return value of -1 with errno |
|
|
1049 | being set to "EINVAL". |
|
|
1050 | |
|
|
1051 | Note that the corresponding "munlockall" is synchronous and is |
|
|
1052 | documented under "MISCELLANEOUS FUNCTIONS". |
|
|
1053 | |
|
|
1054 | Example: asynchronously lock all current and future pages into |
|
|
1055 | memory. |
|
|
1056 | |
|
|
1057 | aio_mlockall IO::AIO::MCL_FUTURE; |
|
|
1058 | |
|
|
1059 | aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents) |
|
|
1060 | Queries the extents of the given file (by calling the Linux "FIEMAP" |
|
|
1061 | ioctl, see <http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for |
|
|
1062 | details). If the ioctl is not available on your OS, then this |
|
|
1063 | request will fail with "ENOSYS". |
|
|
1064 | |
|
|
1065 | $start is the starting offset to query extents for, $length is the |
|
|
1066 | size of the range to query - if it is "undef", then the whole file |
|
|
1067 | will be queried. |
|
|
1068 | |
|
|
1069 | $flags is a combination of flags ("IO::AIO::FIEMAP_FLAG_SYNC" or |
|
|
1070 | "IO::AIO::FIEMAP_FLAG_XATTR" - "IO::AIO::FIEMAP_FLAGS_COMPAT" is |
|
|
1071 | also exported), and is normally 0 or "IO::AIO::FIEMAP_FLAG_SYNC" to |
|
|
1072 | query the data portion. |
|
|
1073 | |
|
|
1074 | $count is the maximum number of extent records to return. If it is |
|
|
1075 | "undef", then IO::AIO queries all extents of the range. As a very |
|
|
1076 | special case, if it is 0, then the callback receives the number of |
|
|
1077 | extents instead of the extents themselves (which is unreliable, see |
|
|
1078 | below). |
|
|
1079 | |
|
|
1080 | If an error occurs, the callback receives no arguments. The special |
|
|
1081 | "errno" value "IO::AIO::EBADR" is available to test for flag errors. |
|
|
1082 | |
|
|
1083 | Otherwise, the callback receives an array reference with extent |
|
|
1084 | structures. Each extent structure is an array reference itself, with |
|
|
1085 | the following members: |
|
|
1086 | |
|
|
1087 | [$logical, $physical, $length, $flags] |
|
|
1088 | |
|
|
1089 | Flags is any combination of the following flag values (typically |
|
|
1090 | either 0 or "IO::AIO::FIEMAP_EXTENT_LAST" (1)): |
|
|
1091 | |
|
|
1092 | "IO::AIO::FIEMAP_EXTENT_LAST", "IO::AIO::FIEMAP_EXTENT_UNKNOWN", |
|
|
1093 | "IO::AIO::FIEMAP_EXTENT_DELALLOC", "IO::AIO::FIEMAP_EXTENT_ENCODED", |
|
|
1094 | "IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED", |
|
|
1095 | "IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED", |
|
|
1096 | "IO::AIO::FIEMAP_EXTENT_DATA_INLINE", |
|
|
1097 | "IO::AIO::FIEMAP_EXTENT_DATA_TAIL", |
|
|
1098 | "IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED" |
|
|
1099 | or "IO::AIO::FIEMAP_EXTENT_SHARED". |
|
|
1100 | |
|
|
1101 | At the time of this writing (Linux 3.2), this request is unreliable |
|
|
1102 | unless $count is "undef", as the kernel has all sorts of bugs |
|
|
1103 | preventing it to return all extents of a range for files with a |
|
|
1104 | large number of extents. The code (only) works around all these |
|
|
1105 | issues if $count is "undef". |
|
|
1106 | |
641 | aio_group $callback->(...) |
1107 | aio_group $callback->(...) |
642 | This is a very special aio request: Instead of doing something, it |
1108 | This is a very special aio request: Instead of doing something, it |
643 | is a container for other aio requests, which is useful if you want |
1109 | is a container for other aio requests, which is useful if you want |
644 | to bundle many requests into a single, composite, request with a |
1110 | to bundle many requests into a single, composite, request with a |
645 | definite callback and the ability to cancel the whole request with |
1111 | definite callback and the ability to cancel the whole request with |
… | |
… | |
678 | While it is theoretically handy to have simple I/O scheduling |
1144 | While it is theoretically handy to have simple I/O scheduling |
679 | requests like sleep and file handle readable/writable, the overhead |
1145 | requests like sleep and file handle readable/writable, the overhead |
680 | this creates is immense (it blocks a thread for a long time) so do |
1146 | this creates is immense (it blocks a thread for a long time) so do |
681 | not use this function except to put your application under |
1147 | not use this function except to put your application under |
682 | artificial I/O pressure. |
1148 | artificial I/O pressure. |
|
|
1149 | |
|
|
1150 | IO::AIO::WD - multiple working directories |
|
|
1151 | Your process only has one current working directory, which is used by |
|
|
1152 | all threads. This makes it hard to use relative paths (some other |
|
|
1153 | component could call "chdir" at any time, and it is hard to control when |
|
|
1154 | the path will be used by IO::AIO). |
|
|
1155 | |
|
|
1156 | One solution for this is to always use absolute paths. This usually |
|
|
1157 | works, but can be quite slow (the kernel has to walk the whole path on |
|
|
1158 | every access), and can also be a hassle to implement. |
|
|
1159 | |
|
|
1160 | Newer POSIX systems have a number of functions (openat, fdopendir, |
|
|
1161 | futimensat and so on) that make it possible to specify working |
|
|
1162 | directories per operation. |
|
|
1163 | |
|
|
1164 | For portability, and because the clowns who "designed", or shall I |
|
|
1165 | write, perpetrated this new interface were obviously half-drunk, this |
|
|
1166 | abstraction cannot be perfect, though. |
|
|
1167 | |
|
|
1168 | IO::AIO allows you to convert directory paths into a so-called |
|
|
1169 | IO::AIO::WD object. This object stores the canonicalised, absolute |
|
|
1170 | version of the path, and on systems that allow it, also a directory file |
|
|
1171 | descriptor. |
|
|
1172 | |
|
|
1173 | Everywhere where a pathname is accepted by IO::AIO (e.g. in "aio_stat" |
|
|
1174 | or "aio_unlink"), one can specify an array reference with an IO::AIO::WD |
|
|
1175 | object and a pathname instead (or the IO::AIO::WD object alone, which |
|
|
1176 | gets interpreted as "[$wd, "."]"). If the pathname is absolute, the |
|
|
1177 | IO::AIO::WD object is ignored, otherwise the pathname is resolved |
|
|
1178 | relative to that IO::AIO::WD object. |
|
|
1179 | |
|
|
1180 | For example, to get a wd object for /etc and then stat passwd inside, |
|
|
1181 | you would write: |
|
|
1182 | |
|
|
1183 | aio_wd "/etc", sub { |
|
|
1184 | my $etcdir = shift; |
|
|
1185 | |
|
|
1186 | # although $etcdir can be undef on error, there is generally no reason |
|
|
1187 | # to check for errors here, as aio_stat will fail with ENOENT |
|
|
1188 | # when $etcdir is undef. |
|
|
1189 | |
|
|
1190 | aio_stat [$etcdir, "passwd"], sub { |
|
|
1191 | # yay |
|
|
1192 | }; |
|
|
1193 | }; |
|
|
1194 | |
|
|
1195 | The fact that "aio_wd" is a request and not a normal function shows that |
|
|
1196 | creating an IO::AIO::WD object is itself a potentially blocking |
|
|
1197 | operation, which is why it is done asynchronously. |
|
|
1198 | |
|
|
1199 | To stat the directory obtained with "aio_wd" above, one could write |
|
|
1200 | either of the following three request calls: |
|
|
1201 | |
|
|
1202 | aio_lstat "/etc" , sub { ... # pathname as normal string |
|
|
1203 | aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself) |
|
|
1204 | aio_lstat $wd , sub { ... # shorthand for the previous |
|
|
1205 | |
|
|
1206 | As with normal pathnames, IO::AIO keeps a copy of the working directory |
|
|
1207 | object and the pathname string, so you could write the following without |
|
|
1208 | causing any issues due to $path getting reused: |
|
|
1209 | |
|
|
1210 | my $path = [$wd, undef]; |
|
|
1211 | |
|
|
1212 | for my $name (qw(abc def ghi)) { |
|
|
1213 | $path->[1] = $name; |
|
|
1214 | aio_stat $path, sub { |
|
|
1215 | # ... |
|
|
1216 | }; |
|
|
1217 | } |
|
|
1218 | |
|
|
1219 | There are some caveats: when directories get renamed (or deleted), the |
|
|
1220 | pathname string doesn't change, so will point to the new directory (or |
|
|
1221 | nowhere at all), while the directory fd, if available on the system, |
|
|
1222 | will still point to the original directory. Most functions accepting a |
|
|
1223 | pathname will use the directory fd on newer systems, and the string on |
|
|
1224 | older systems. Some functions (such as "aio_realpath") will always rely |
|
|
1225 | on the string form of the pathname. |
|
|
1226 | |
|
|
1227 | So this functionality is mainly useful to get some protection against |
|
|
1228 | "chdir", to easily get an absolute path out of a relative path for |
|
|
1229 | future reference, and to speed up doing many operations in the same |
|
|
1230 | directory (e.g. when stat'ing all files in a directory). |
|
|
1231 | |
|
|
1232 | The following functions implement this working directory abstraction: |
|
|
1233 | |
|
|
1234 | aio_wd $pathname, $callback->($wd) |
|
|
1235 | Asynchonously canonicalise the given pathname and convert it to an |
|
|
1236 | IO::AIO::WD object representing it. If possible and supported on the |
|
|
1237 | system, also open a directory fd to speed up pathname resolution |
|
|
1238 | relative to this working directory. |
|
|
1239 | |
|
|
1240 | If something goes wrong, then "undef" is passwd to the callback |
|
|
1241 | instead of a working directory object and $! is set appropriately. |
|
|
1242 | Since passing "undef" as working directory component of a pathname |
|
|
1243 | fails the request with "ENOENT", there is often no need for error |
|
|
1244 | checking in the "aio_wd" callback, as future requests using the |
|
|
1245 | value will fail in the expected way. |
|
|
1246 | |
|
|
1247 | IO::AIO::CWD |
|
|
1248 | This is a compiletime constant (object) that represents the process |
|
|
1249 | current working directory. |
|
|
1250 | |
|
|
1251 | Specifying this object as working directory object for a pathname is |
|
|
1252 | as if the pathname would be specified directly, without a directory |
|
|
1253 | object. For example, these calls are functionally identical: |
|
|
1254 | |
|
|
1255 | aio_stat "somefile", sub { ... }; |
|
|
1256 | aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; |
|
|
1257 | |
|
|
1258 | To recover the path associated with an IO::AIO::WD object, you can use |
|
|
1259 | "aio_realpath": |
|
|
1260 | |
|
|
1261 | aio_realpath $wd, sub { |
|
|
1262 | warn "path is $_[0]\n"; |
|
|
1263 | }; |
|
|
1264 | |
|
|
1265 | Currently, "aio_statvfs" always, and "aio_rename" and "aio_rmdir" |
|
|
1266 | sometimes, fall back to using an absolue path. |
683 | |
1267 | |
684 | IO::AIO::REQ CLASS |
1268 | IO::AIO::REQ CLASS |
685 | All non-aggregate "aio_*" functions return an object of this class when |
1269 | All non-aggregate "aio_*" functions return an object of this class when |
686 | called in non-void context. |
1270 | called in non-void context. |
687 | |
1271 | |
… | |
… | |
761 | $grp->cancel_subs |
1345 | $grp->cancel_subs |
762 | Cancel all subrequests and clears any feeder, but not the group |
1346 | Cancel all subrequests and clears any feeder, but not the group |
763 | request itself. Useful when you queued a lot of events but got a |
1347 | request itself. Useful when you queued a lot of events but got a |
764 | result early. |
1348 | result early. |
765 | |
1349 | |
|
|
1350 | The group request will finish normally (you cannot add requests to |
|
|
1351 | the group). |
|
|
1352 | |
766 | $grp->result (...) |
1353 | $grp->result (...) |
767 | Set the result value(s) that will be passed to the group callback |
1354 | Set the result value(s) that will be passed to the group callback |
768 | when all subrequests have finished and set the groups errno to the |
1355 | when all subrequests have finished and set the groups errno to the |
769 | current value of errno (just like calling "errno" without an error |
1356 | current value of errno (just like calling "errno" without an error |
770 | number). By default, no argument will be passed and errno is zero. |
1357 | number). By default, no argument will be passed and errno is zero. |
… | |
… | |
784 | Sets a feeder/generator on this group: every group can have an |
1371 | Sets a feeder/generator on this group: every group can have an |
785 | attached generator that generates requests if idle. The idea behind |
1372 | attached generator that generates requests if idle. The idea behind |
786 | this is that, although you could just queue as many requests as you |
1373 | this is that, although you could just queue as many requests as you |
787 | want in a group, this might starve other requests for a potentially |
1374 | want in a group, this might starve other requests for a potentially |
788 | long time. For example, "aio_scandir" might generate hundreds of |
1375 | long time. For example, "aio_scandir" might generate hundreds of |
789 | thousands "aio_stat" requests, delaying any later requests for a |
1376 | thousands of "aio_stat" requests, delaying any later requests for a |
790 | long time. |
1377 | long time. |
791 | |
1378 | |
792 | To avoid this, and allow incremental generation of requests, you can |
1379 | To avoid this, and allow incremental generation of requests, you can |
793 | instead a group and set a feeder on it that generates those |
1380 | instead a group and set a feeder on it that generates those |
794 | requests. The feed callback will be called whenever there are few |
1381 | requests. The feed callback will be called whenever there are few |
… | |
… | |
836 | results. |
1423 | results. |
837 | |
1424 | |
838 | See "poll_cb" for an example. |
1425 | See "poll_cb" for an example. |
839 | |
1426 | |
840 | IO::AIO::poll_cb |
1427 | IO::AIO::poll_cb |
841 | Process some outstanding events on the result pipe. You have to call |
1428 | Process some requests that have reached the result phase (i.e. they |
842 | this regularly. Returns 0 if all events could be processed, or -1 if |
1429 | have been executed but the results are not yet reported). You have |
843 | it returned earlier for whatever reason. Returns immediately when no |
1430 | to call this "regularly" to finish outstanding requests. |
844 | events are outstanding. The amount of events processed depends on |
|
|
845 | the settings of "IO::AIO::max_poll_req" and |
|
|
846 | "IO::AIO::max_poll_time". |
|
|
847 | |
1431 | |
|
|
1432 | Returns 0 if all events could be processed (or there were no events |
|
|
1433 | to process), or -1 if it returned earlier for whatever reason. |
|
|
1434 | Returns immediately when no events are outstanding. The amount of |
|
|
1435 | events processed depends on the settings of "IO::AIO::max_poll_req", |
|
|
1436 | "IO::AIO::max_poll_time" and "IO::AIO::max_outstanding". |
|
|
1437 | |
848 | If not all requests were processed for whatever reason, the |
1438 | If not all requests were processed for whatever reason, the poll |
849 | filehandle will still be ready when "poll_cb" returns, so normally |
1439 | file descriptor will still be ready when "poll_cb" returns, so |
850 | you don't have to do anything special to have it called later. |
1440 | normally you don't have to do anything special to have it called |
|
|
1441 | later. |
|
|
1442 | |
|
|
1443 | Apart from calling "IO::AIO::poll_cb" when the event filehandle |
|
|
1444 | becomes ready, it can be beneficial to call this function from loops |
|
|
1445 | which submit a lot of requests, to make sure the results get |
|
|
1446 | processed when they become available and not just when the loop is |
|
|
1447 | finished and the event loop takes over again. This function returns |
|
|
1448 | very fast when there are no outstanding requests. |
851 | |
1449 | |
852 | Example: Install an Event watcher that automatically calls |
1450 | Example: Install an Event watcher that automatically calls |
853 | IO::AIO::poll_cb with high priority (more examples can be found in |
1451 | IO::AIO::poll_cb with high priority (more examples can be found in |
854 | the SYNOPSIS section, at the top of this document): |
1452 | the SYNOPSIS section, at the top of this document): |
855 | |
1453 | |
856 | Event->io (fd => IO::AIO::poll_fileno, |
1454 | Event->io (fd => IO::AIO::poll_fileno, |
857 | poll => 'r', async => 1, |
1455 | poll => 'r', async => 1, |
858 | cb => \&IO::AIO::poll_cb); |
1456 | cb => \&IO::AIO::poll_cb); |
|
|
1457 | |
|
|
1458 | IO::AIO::poll_wait |
|
|
1459 | Wait until either at least one request is in the result phase or no |
|
|
1460 | requests are outstanding anymore. |
|
|
1461 | |
|
|
1462 | This is useful if you want to synchronously wait for some requests |
|
|
1463 | to become ready, without actually handling them. |
|
|
1464 | |
|
|
1465 | See "nreqs" for an example. |
|
|
1466 | |
|
|
1467 | IO::AIO::poll |
|
|
1468 | Waits until some requests have been handled. |
|
|
1469 | |
|
|
1470 | Returns the number of requests processed, but is otherwise strictly |
|
|
1471 | equivalent to: |
|
|
1472 | |
|
|
1473 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1474 | |
|
|
1475 | IO::AIO::flush |
|
|
1476 | Wait till all outstanding AIO requests have been handled. |
|
|
1477 | |
|
|
1478 | Strictly equivalent to: |
|
|
1479 | |
|
|
1480 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1481 | while IO::AIO::nreqs; |
|
|
1482 | |
|
|
1483 | This function can be useful at program aborts, to make sure |
|
|
1484 | outstanding I/O has been done ("IO::AIO" uses an "END" block which |
|
|
1485 | already calls this function on normal exits), or when you are merely |
|
|
1486 | using "IO::AIO" for its more advanced functions, rather than for |
|
|
1487 | async I/O, e.g.: |
|
|
1488 | |
|
|
1489 | my ($dirs, $nondirs); |
|
|
1490 | IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ }; |
|
|
1491 | IO::AIO::flush; |
|
|
1492 | # $dirs, $nondirs are now set |
859 | |
1493 | |
860 | IO::AIO::max_poll_reqs $nreqs |
1494 | IO::AIO::max_poll_reqs $nreqs |
861 | IO::AIO::max_poll_time $seconds |
1495 | IO::AIO::max_poll_time $seconds |
862 | These set the maximum number of requests (default 0, meaning |
1496 | These set the maximum number of requests (default 0, meaning |
863 | infinity) that are being processed by "IO::AIO::poll_cb" in one |
1497 | infinity) that are being processed by "IO::AIO::poll_cb" in one |
… | |
… | |
887 | # use a low priority so other tasks have priority |
1521 | # use a low priority so other tasks have priority |
888 | Event->io (fd => IO::AIO::poll_fileno, |
1522 | Event->io (fd => IO::AIO::poll_fileno, |
889 | poll => 'r', nice => 1, |
1523 | poll => 'r', nice => 1, |
890 | cb => &IO::AIO::poll_cb); |
1524 | cb => &IO::AIO::poll_cb); |
891 | |
1525 | |
892 | IO::AIO::poll_wait |
|
|
893 | If there are any outstanding requests and none of them in the result |
|
|
894 | phase, wait till the result filehandle becomes ready for reading |
|
|
895 | (simply does a "select" on the filehandle. This is useful if you |
|
|
896 | want to synchronously wait for some requests to finish). |
|
|
897 | |
|
|
898 | See "nreqs" for an example. |
|
|
899 | |
|
|
900 | IO::AIO::poll |
|
|
901 | Waits until some requests have been handled. |
|
|
902 | |
|
|
903 | Returns the number of requests processed, but is otherwise strictly |
|
|
904 | equivalent to: |
|
|
905 | |
|
|
906 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
907 | |
|
|
908 | IO::AIO::flush |
|
|
909 | Wait till all outstanding AIO requests have been handled. |
|
|
910 | |
|
|
911 | Strictly equivalent to: |
|
|
912 | |
|
|
913 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
914 | while IO::AIO::nreqs; |
|
|
915 | |
|
|
916 | CONTROLLING THE NUMBER OF THREADS |
1526 | CONTROLLING THE NUMBER OF THREADS |
917 | IO::AIO::min_parallel $nthreads |
1527 | IO::AIO::min_parallel $nthreads |
918 | Set the minimum number of AIO threads to $nthreads. The current |
1528 | Set the minimum number of AIO threads to $nthreads. The current |
919 | default is 8, which means eight asynchronous operations can execute |
1529 | default is 8, which means eight asynchronous operations can execute |
920 | concurrently at any one time (the number of outstanding requests, |
1530 | concurrently at any one time (the number of outstanding requests, |
… | |
… | |
949 | |
1559 | |
950 | Under normal circumstances you don't need to call this function. |
1560 | Under normal circumstances you don't need to call this function. |
951 | |
1561 | |
952 | IO::AIO::max_idle $nthreads |
1562 | IO::AIO::max_idle $nthreads |
953 | Limit the number of threads (default: 4) that are allowed to idle |
1563 | Limit the number of threads (default: 4) that are allowed to idle |
954 | (i.e., threads that did not get a request to process within 10 |
1564 | (i.e., threads that did not get a request to process within the idle |
955 | seconds). That means if a thread becomes idle while $nthreads other |
1565 | timeout (default: 10 seconds). That means if a thread becomes idle |
956 | threads are also idle, it will free its resources and exit. |
1566 | while $nthreads other threads are also idle, it will free its |
|
|
1567 | resources and exit. |
957 | |
1568 | |
958 | This is useful when you allow a large number of threads (e.g. 100 or |
1569 | This is useful when you allow a large number of threads (e.g. 100 or |
959 | 1000) to allow for extremely high load situations, but want to free |
1570 | 1000) to allow for extremely high load situations, but want to free |
960 | resources under normal circumstances (1000 threads can easily |
1571 | resources under normal circumstances (1000 threads can easily |
961 | consume 30MB of RAM). |
1572 | consume 30MB of RAM). |
962 | |
1573 | |
963 | The default is probably ok in most situations, especially if thread |
1574 | The default is probably ok in most situations, especially if thread |
964 | creation is fast. If thread creation is very slow on your system you |
1575 | creation is fast. If thread creation is very slow on your system you |
965 | might want to use larger values. |
1576 | might want to use larger values. |
966 | |
1577 | |
|
|
1578 | IO::AIO::idle_timeout $seconds |
|
|
1579 | Sets the minimum idle timeout (default 10) after which worker |
|
|
1580 | threads are allowed to exit. SEe "IO::AIO::max_idle". |
|
|
1581 | |
967 | IO::AIO::max_outstanding $maxreqs |
1582 | IO::AIO::max_outstanding $maxreqs |
|
|
1583 | Sets the maximum number of outstanding requests to $nreqs. If you do |
|
|
1584 | queue up more than this number of requests, the next call to |
|
|
1585 | "IO::AIO::poll_cb" (and other functions calling "poll_cb", such as |
|
|
1586 | "IO::AIO::flush" or "IO::AIO::poll") will block until the limit is |
|
|
1587 | no longer exceeded. |
|
|
1588 | |
|
|
1589 | In other words, this setting does not enforce a queue limit, but can |
|
|
1590 | be used to make poll functions block if the limit is exceeded. |
|
|
1591 | |
968 | This is a very bad function to use in interactive programs because |
1592 | This is a very bad function to use in interactive programs because |
969 | it blocks, and a bad way to reduce concurrency because it is |
1593 | it blocks, and a bad way to reduce concurrency because it is |
970 | inexact: Better use an "aio_group" together with a feed callback. |
1594 | inexact: Better use an "aio_group" together with a feed callback. |
971 | |
1595 | |
972 | Sets the maximum number of outstanding requests to $nreqs. If you do |
1596 | Its main use is in scripts without an event loop - when you want to |
973 | queue up more than this number of requests, the next call to the |
1597 | stat a lot of files, you can write something like this: |
974 | "poll_cb" (and "poll_some" and other functions calling "poll_cb") |
|
|
975 | function will block until the limit is no longer exceeded. |
|
|
976 | |
1598 | |
977 | The default value is very large, so there is no practical limit on |
1599 | IO::AIO::max_outstanding 32; |
|
|
1600 | |
|
|
1601 | for my $path (...) { |
|
|
1602 | aio_stat $path , ...; |
|
|
1603 | IO::AIO::poll_cb; |
|
|
1604 | } |
|
|
1605 | |
|
|
1606 | IO::AIO::flush; |
|
|
1607 | |
|
|
1608 | The call to "poll_cb" inside the loop will normally return |
|
|
1609 | instantly, but as soon as more thna 32 reqeusts are in-flight, it |
|
|
1610 | will block until some requests have been handled. This keeps the |
|
|
1611 | loop from pushing a large number of "aio_stat" requests onto the |
|
|
1612 | queue. |
|
|
1613 | |
|
|
1614 | The default value for "max_outstanding" is very large, so there is |
978 | the number of outstanding requests. |
1615 | no practical limit on the number of outstanding requests. |
979 | |
|
|
980 | You can still queue as many requests as you want. Therefore, |
|
|
981 | "max_outstanding" is mainly useful in simple scripts (with low |
|
|
982 | values) or as a stop gap to shield against fatal memory overflow |
|
|
983 | (with large values). |
|
|
984 | |
1616 | |
985 | STATISTICAL INFORMATION |
1617 | STATISTICAL INFORMATION |
986 | IO::AIO::nreqs |
1618 | IO::AIO::nreqs |
987 | Returns the number of requests currently in the ready, execute or |
1619 | Returns the number of requests currently in the ready, execute or |
988 | pending states (i.e. for which their callback has not been invoked |
1620 | pending states (i.e. for which their callback has not been invoked |
… | |
… | |
999 | |
1631 | |
1000 | IO::AIO::npending |
1632 | IO::AIO::npending |
1001 | Returns the number of requests currently in the pending state |
1633 | Returns the number of requests currently in the pending state |
1002 | (executed, but not yet processed by poll_cb). |
1634 | (executed, but not yet processed by poll_cb). |
1003 | |
1635 | |
|
|
1636 | SUBSECOND STAT TIME ACCESS |
|
|
1637 | Both "aio_stat"/"aio_lstat" and perl's "stat"/"lstat" functions can |
|
|
1638 | generally find access/modification and change times with subsecond time |
|
|
1639 | accuracy of the system supports it, but perl's built-in functions only |
|
|
1640 | return the integer part. |
|
|
1641 | |
|
|
1642 | The following functions return the timestamps of the most recent stat |
|
|
1643 | with subsecond precision on most systems and work both after |
|
|
1644 | "aio_stat"/"aio_lstat" and perl's "stat"/"lstat" calls. Their return |
|
|
1645 | value is only meaningful after a successful "stat"/"lstat" call, or |
|
|
1646 | during/after a successful "aio_stat"/"aio_lstat" callback. |
|
|
1647 | |
|
|
1648 | This is similar to the Time::HiRes "stat" functions, but can return full |
|
|
1649 | resolution without rounding and work with standard perl "stat", |
|
|
1650 | alleviating the need to call the special "Time::HiRes" functions, which |
|
|
1651 | do not act like their perl counterparts. |
|
|
1652 | |
|
|
1653 | On operating systems or file systems where subsecond time resolution is |
|
|
1654 | not supported or could not be detected, a fractional part of 0 is |
|
|
1655 | returned, so it is always safe to call these functions. |
|
|
1656 | |
|
|
1657 | $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, |
|
|
1658 | IO::AIO::st_btime |
|
|
1659 | Return the access, modication, change or birth time, respectively, |
|
|
1660 | including fractional part. Due to the limited precision of floating |
|
|
1661 | point, the accuracy on most platforms is only a bit better than |
|
|
1662 | milliseconds for times around now - see the *nsec* function family, |
|
|
1663 | below, for full accuracy. |
|
|
1664 | |
|
|
1665 | File birth time is only available when the OS and perl support it |
|
|
1666 | (on FreeBSD and NetBSD at the time of this writing, although support |
|
|
1667 | is adaptive, so if your OS/perl gains support, IO::AIO can take |
|
|
1668 | advantage of it). On systems where it isn't available, 0 is |
|
|
1669 | currently returned, but this might change to "undef" in a future |
|
|
1670 | version. |
|
|
1671 | |
|
|
1672 | ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime |
|
|
1673 | Returns access, modification, change and birth time all in one go, |
|
|
1674 | and maybe more times in the future version. |
|
|
1675 | |
|
|
1676 | $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, |
|
|
1677 | IO::AIO::st_ctimensec, IO::AIO::st_btimensec |
|
|
1678 | Return the fractional access, modifcation, change or birth time, in |
|
|
1679 | nanoseconds, as an integer in the range 0 to 999999999. |
|
|
1680 | |
|
|
1681 | Note that no accessors are provided for access, modification and |
|
|
1682 | change times - you need to get those from "stat _" if required ("int |
|
|
1683 | IO::AIO::st_atime" and so on will *not* generally give you the |
|
|
1684 | correct value). |
|
|
1685 | |
|
|
1686 | $seconds = IO::AIO::st_btimesec |
|
|
1687 | The (integral) seconds part of the file birth time, if available. |
|
|
1688 | |
|
|
1689 | ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec |
|
|
1690 | Like the functions above, but returns all four times in one go (and |
|
|
1691 | maybe more in future versions). |
|
|
1692 | |
|
|
1693 | $counter = IO::AIO::st_gen |
|
|
1694 | Returns the generation counter (in practice this is just a random |
|
|
1695 | number) of the file. This is only available on platforms which have |
|
|
1696 | this member in their "struct stat" (most BSDs at the time of this |
|
|
1697 | writing) and generally only to the root usert. If unsupported, 0 is |
|
|
1698 | returned, but this might change to "undef" in a future version. |
|
|
1699 | |
|
|
1700 | Example: print the high resolution modification time of /etc, using |
|
|
1701 | "stat", and "IO::AIO::aio_stat". |
|
|
1702 | |
|
|
1703 | if (stat "/etc") { |
|
|
1704 | printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime; |
|
|
1705 | } |
|
|
1706 | |
|
|
1707 | IO::AIO::aio_stat "/etc", sub { |
|
|
1708 | $_[0] |
|
|
1709 | and return; |
|
|
1710 | |
|
|
1711 | printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec; |
|
|
1712 | }; |
|
|
1713 | |
|
|
1714 | IO::AIO::flush; |
|
|
1715 | |
|
|
1716 | Output of the awbove on my system, showing reduced and full accuracy: |
|
|
1717 | |
|
|
1718 | stat(/etc) mtime: 1534043702.020808 |
|
|
1719 | aio_stat(/etc) mtime: 1534043702.020807792 |
|
|
1720 | |
1004 | MISCELLANEOUS FUNCTIONS |
1721 | MISCELLANEOUS FUNCTIONS |
1005 | IO::AIO implements some functions that might be useful, but are not |
1722 | IO::AIO implements some functions that are useful when you want to use |
1006 | asynchronous. |
1723 | some "Advanced I/O" function not available to in Perl, without going the |
|
|
1724 | "Asynchronous I/O" route. Many of these have an asynchronous "aio_*" |
|
|
1725 | counterpart. |
|
|
1726 | |
|
|
1727 | $numfd = IO::AIO::get_fdlimit |
|
|
1728 | This function is *EXPERIMENTAL* and subject to change. |
|
|
1729 | |
|
|
1730 | Tries to find the current file descriptor limit and returns it, or |
|
|
1731 | "undef" and sets $! in case of an error. The limit is one larger |
|
|
1732 | than the highest valid file descriptor number. |
|
|
1733 | |
|
|
1734 | IO::AIO::min_fdlimit [$numfd] |
|
|
1735 | This function is *EXPERIMENTAL* and subject to change. |
|
|
1736 | |
|
|
1737 | Try to increase the current file descriptor limit(s) to at least |
|
|
1738 | $numfd by changing the soft or hard file descriptor resource limit. |
|
|
1739 | If $numfd is missing, it will try to set a very high limit, although |
|
|
1740 | this is not recommended when you know the actual minimum that you |
|
|
1741 | require. |
|
|
1742 | |
|
|
1743 | If the limit cannot be raised enough, the function makes a |
|
|
1744 | best-effort attempt to increase the limit as much as possible, using |
|
|
1745 | various tricks, while still failing. You can query the resulting |
|
|
1746 | limit using "IO::AIO::get_fdlimit". |
|
|
1747 | |
|
|
1748 | If an error occurs, returns "undef" and sets $!, otherwise returns |
|
|
1749 | true. |
1007 | |
1750 | |
1008 | IO::AIO::sendfile $ofh, $ifh, $offset, $count |
1751 | IO::AIO::sendfile $ofh, $ifh, $offset, $count |
1009 | Calls the "eio_sendfile_sync" function, which is like |
1752 | Calls the "eio_sendfile_sync" function, which is like |
1010 | "aio_sendfile", but is blocking (this makes most sense if you know |
1753 | "aio_sendfile", but is blocking (this makes most sense if you know |
1011 | the input data is likely cached already and the output filehandle is |
1754 | the input data is likely cached already and the output filehandle is |
1012 | set to non-blocking operations). |
1755 | set to non-blocking operations). |
1013 | |
1756 | |
1014 | Returns the number of bytes copied, or -1 on error. |
1757 | Returns the number of bytes copied, or -1 on error. |
1015 | |
1758 | |
1016 | IO::AIO::fadvise $fh, $offset, $len, $advice |
1759 | IO::AIO::fadvise $fh, $offset, $len, $advice |
1017 | Simply calls the "posix_fadvise" function (see it's manpage for |
1760 | Simply calls the "posix_fadvise" function (see its manpage for |
1018 | details). The following advice constants are avaiable: |
1761 | details). The following advice constants are available: |
1019 | "IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL", |
1762 | "IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL", |
1020 | "IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE", |
1763 | "IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE", |
1021 | "IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED". |
1764 | "IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED". |
1022 | |
1765 | |
1023 | On systems that do not implement "posix_fadvise", this function |
1766 | On systems that do not implement "posix_fadvise", this function |
1024 | returns ENOSYS, otherwise the return value of "posix_fadvise". |
1767 | returns ENOSYS, otherwise the return value of "posix_fadvise". |
1025 | |
1768 | |
|
|
1769 | IO::AIO::madvise $scalar, $offset, $len, $advice |
|
|
1770 | Simply calls the "posix_madvise" function (see its manpage for |
|
|
1771 | details). The following advice constants are available: |
|
|
1772 | "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL", |
|
|
1773 | "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED", |
|
|
1774 | "IO::AIO::MADV_DONTNEED". |
|
|
1775 | |
|
|
1776 | If $offset is negative, counts from the end. If $length is negative, |
|
|
1777 | the remaining length of the $scalar is used. If possible, $length |
|
|
1778 | will be reduced to fit into the $scalar. |
|
|
1779 | |
|
|
1780 | On systems that do not implement "posix_madvise", this function |
|
|
1781 | returns ENOSYS, otherwise the return value of "posix_madvise". |
|
|
1782 | |
|
|
1783 | IO::AIO::mprotect $scalar, $offset, $len, $protect |
|
|
1784 | Simply calls the "mprotect" function on the preferably AIO::mmap'ed |
|
|
1785 | $scalar (see its manpage for details). The following protect |
|
|
1786 | constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ", |
|
|
1787 | "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC". |
|
|
1788 | |
|
|
1789 | If $offset is negative, counts from the end. If $length is negative, |
|
|
1790 | the remaining length of the $scalar is used. If possible, $length |
|
|
1791 | will be reduced to fit into the $scalar. |
|
|
1792 | |
|
|
1793 | On systems that do not implement "mprotect", this function returns |
|
|
1794 | ENOSYS, otherwise the return value of "mprotect". |
|
|
1795 | |
|
|
1796 | IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] |
|
|
1797 | Memory-maps a file (or anonymous memory range) and attaches it to |
|
|
1798 | the given $scalar, which will act like a string scalar. Returns true |
|
|
1799 | on success, and false otherwise. |
|
|
1800 | |
|
|
1801 | The scalar must exist, but its contents do not matter - this means |
|
|
1802 | you cannot use a nonexistant array or hash element. When in doubt, |
|
|
1803 | "undef" the scalar first. |
|
|
1804 | |
|
|
1805 | The only operations allowed on the mmapped scalar are |
|
|
1806 | "substr"/"vec", which don't change the string length, and most |
|
|
1807 | read-only operations such as copying it or searching it with regexes |
|
|
1808 | and so on. |
|
|
1809 | |
|
|
1810 | Anything else is unsafe and will, at best, result in memory leaks. |
|
|
1811 | |
|
|
1812 | The memory map associated with the $scalar is automatically removed |
|
|
1813 | when the $scalar is undef'd or destroyed, or when the |
|
|
1814 | "IO::AIO::mmap" or "IO::AIO::munmap" functions are called on it. |
|
|
1815 | |
|
|
1816 | This calls the "mmap"(2) function internally. See your system's |
|
|
1817 | manual page for details on the $length, $prot and $flags parameters. |
|
|
1818 | |
|
|
1819 | The $length must be larger than zero and smaller than the actual |
|
|
1820 | filesize. |
|
|
1821 | |
|
|
1822 | $prot is a combination of "IO::AIO::PROT_NONE", |
|
|
1823 | "IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or |
|
|
1824 | "IO::AIO::PROT_WRITE", |
|
|
1825 | |
|
|
1826 | $flags can be a combination of "IO::AIO::MAP_SHARED" or |
|
|
1827 | "IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when |
|
|
1828 | not available, the are 0): "IO::AIO::MAP_ANONYMOUS" (which is set to |
|
|
1829 | "MAP_ANON" if your system only provides this constant), |
|
|
1830 | "IO::AIO::MAP_LOCKED", "IO::AIO::MAP_NORESERVE", |
|
|
1831 | "IO::AIO::MAP_POPULATE", "IO::AIO::MAP_NONBLOCK", |
|
|
1832 | "IO::AIO::MAP_FIXED", "IO::AIO::MAP_GROWSDOWN", |
|
|
1833 | "IO::AIO::MAP_32BIT", "IO::AIO::MAP_HUGETLB" or |
|
|
1834 | "IO::AIO::MAP_STACK". |
|
|
1835 | |
|
|
1836 | If $fh is "undef", then a file descriptor of -1 is passed. |
|
|
1837 | |
|
|
1838 | $offset is the offset from the start of the file - it generally must |
|
|
1839 | be a multiple of "IO::AIO::PAGESIZE" and defaults to 0. |
|
|
1840 | |
|
|
1841 | Example: |
|
|
1842 | |
|
|
1843 | use Digest::MD5; |
|
|
1844 | use IO::AIO; |
|
|
1845 | |
|
|
1846 | open my $fh, "<verybigfile" |
|
|
1847 | or die "$!"; |
|
|
1848 | |
|
|
1849 | IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh |
|
|
1850 | or die "verybigfile: $!"; |
|
|
1851 | |
|
|
1852 | my $fast_md5 = md5 $data; |
|
|
1853 | |
|
|
1854 | IO::AIO::munmap $scalar |
|
|
1855 | Removes a previous mmap and undefines the $scalar. |
|
|
1856 | |
|
|
1857 | IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, |
|
|
1858 | $new_address = 0] |
|
|
1859 | Calls the Linux-specific mremap(2) system call. The $scalar must |
|
|
1860 | have been mapped by "IO::AIO::mmap", and $flags must currently |
|
|
1861 | either be 0 or "IO::AIO::MREMAP_MAYMOVE". |
|
|
1862 | |
|
|
1863 | Returns true if successful, and false otherwise. If the underlying |
|
|
1864 | mmapped region has changed address, then the true value has the |
|
|
1865 | numerical value 1, otherwise it has the numerical value 0: |
|
|
1866 | |
|
|
1867 | my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE |
|
|
1868 | or die "mremap: $!"; |
|
|
1869 | |
|
|
1870 | if ($success*1) { |
|
|
1871 | warn "scalar has chanegd address in memory\n"; |
|
|
1872 | } |
|
|
1873 | |
|
|
1874 | "IO::AIO::MREMAP_FIXED" and the $new_address argument are currently |
|
|
1875 | implemented, but not supported and might go away in a future |
|
|
1876 | version. |
|
|
1877 | |
|
|
1878 | On systems where this call is not supported or is not emulated, this |
|
|
1879 | call returns falls and sets $! to "ENOSYS". |
|
|
1880 | |
|
|
1881 | IO::AIO::mlockall $flags |
|
|
1882 | Calls the "eio_mlockall_sync" function, which is like |
|
|
1883 | "aio_mlockall", but is blocking. |
|
|
1884 | |
|
|
1885 | IO::AIO::munlock $scalar, $offset = 0, $length = undef |
|
|
1886 | Calls the "munlock" function, undoing the effects of a previous |
|
|
1887 | "aio_mlock" call (see its description for details). |
|
|
1888 | |
|
|
1889 | IO::AIO::munlockall |
|
|
1890 | Calls the "munlockall" function. |
|
|
1891 | |
|
|
1892 | On systems that do not implement "munlockall", this function returns |
|
|
1893 | ENOSYS, otherwise the return value of "munlockall". |
|
|
1894 | |
|
|
1895 | IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags |
|
|
1896 | Calls the GNU/Linux splice(2) syscall, if available. If $r_off or |
|
|
1897 | $w_off are "undef", then "NULL" is passed for these, otherwise they |
|
|
1898 | should be the file offset. |
|
|
1899 | |
|
|
1900 | $r_fh and $w_fh should not refer to the same file, as splice might |
|
|
1901 | silently corrupt the data in this case. |
|
|
1902 | |
|
|
1903 | The following symbol flag values are available: |
|
|
1904 | "IO::AIO::SPLICE_F_MOVE", "IO::AIO::SPLICE_F_NONBLOCK", |
|
|
1905 | "IO::AIO::SPLICE_F_MORE" and "IO::AIO::SPLICE_F_GIFT". |
|
|
1906 | |
|
|
1907 | See the splice(2) manpage for details. |
|
|
1908 | |
|
|
1909 | IO::AIO::tee $r_fh, $w_fh, $length, $flags |
|
|
1910 | Calls the GNU/Linux tee(2) syscall, see its manpage and the |
|
|
1911 | description for "IO::AIO::splice" above for details. |
|
|
1912 | |
|
|
1913 | $actual_size = IO::AIO::pipesize $r_fh[, $new_size] |
|
|
1914 | Attempts to query or change the pipe buffer size. Obviously works |
|
|
1915 | only on pipes, and currently works only on GNU/Linux systems, and |
|
|
1916 | fails with -1/"ENOSYS" everywhere else. If anybody knows how to |
|
|
1917 | influence pipe buffer size on other systems, drop me a note. |
|
|
1918 | |
|
|
1919 | ($rfh, $wfh) = IO::AIO::pipe2 [$flags] |
|
|
1920 | This is a direct interface to the Linux pipe2(2) system call. If |
|
|
1921 | $flags is missing or 0, then this should be the same as a call to |
|
|
1922 | perl's built-in "pipe" function and create a new pipe, and works on |
|
|
1923 | systems that lack the pipe2 syscall. On win32, this case invokes |
|
|
1924 | "_pipe (..., 4096, O_BINARY)". |
|
|
1925 | |
|
|
1926 | If $flags is non-zero, it tries to invoke the pipe2 system call with |
|
|
1927 | the given flags (Linux 2.6.27, glibc 2.9). |
|
|
1928 | |
|
|
1929 | On success, the read and write file handles are returned. |
|
|
1930 | |
|
|
1931 | On error, nothing will be returned. If the pipe2 syscall is missing |
|
|
1932 | and $flags is non-zero, fails with "ENOSYS". |
|
|
1933 | |
|
|
1934 | Please refer to pipe2(2) for more info on the $flags, but at the |
|
|
1935 | time of this writing, "IO::AIO::O_CLOEXEC", "IO::AIO::O_NONBLOCK" |
|
|
1936 | and "IO::AIO::O_DIRECT" (Linux 3.4, for packet-based pipes) were |
|
|
1937 | supported. |
|
|
1938 | |
|
|
1939 | Example: create a pipe race-free w.r.t. threads and fork: |
|
|
1940 | |
|
|
1941 | my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC |
|
|
1942 | or die "pipe2: $!\n"; |
|
|
1943 | |
|
|
1944 | $fh = IO::AIO::memfd_create $pathname[, $flags] |
|
|
1945 | This is a direct interface to the Linux memfd_create(2) system call. |
|
|
1946 | The (unhelpful) default for $flags is 0, but your default should be |
|
|
1947 | "IO::AIO::MFD_CLOEXEC". |
|
|
1948 | |
|
|
1949 | On success, the new memfd filehandle is returned, otherwise returns |
|
|
1950 | "undef". If the memfd_create syscall is missing, fails with |
|
|
1951 | "ENOSYS". |
|
|
1952 | |
|
|
1953 | Please refer to memfd_create(2) for more info on this call. |
|
|
1954 | |
|
|
1955 | The following $flags values are available: "IO::AIO::MFD_CLOEXEC", |
|
|
1956 | "IO::AIO::MFD_ALLOW_SEALING" and "IO::AIO::MFD_HUGETLB". |
|
|
1957 | |
|
|
1958 | Example: create a new memfd. |
|
|
1959 | |
|
|
1960 | my $fh = IO::AIO::memfd_create "somenameforprocfd", IO::AIO::MFD_CLOEXEC |
|
|
1961 | or die "m,emfd_create: $!\n"; |
|
|
1962 | =item $fh = IO::AIO::eventfd [$initval, [$flags]] |
|
|
1963 | |
|
|
1964 | This is a direct interface to the Linux eventfd(2) system call. The |
|
|
1965 | (unhelpful) defaults for $initval and $flags are 0 for both. |
|
|
1966 | |
|
|
1967 | On success, the new eventfd filehandle is returned, otherwise |
|
|
1968 | returns "undef". If the eventfd syscall is missing, fails with |
|
|
1969 | "ENOSYS". |
|
|
1970 | |
|
|
1971 | Please refer to eventfd(2) for more info on this call. |
|
|
1972 | |
|
|
1973 | The following symbol flag values are available: |
|
|
1974 | "IO::AIO::EFD_CLOEXEC", "IO::AIO::EFD_NONBLOCK" and |
|
|
1975 | "IO::AIO::EFD_SEMAPHORE" (Linux 2.6.30). |
|
|
1976 | |
|
|
1977 | Example: create a new eventfd filehandle: |
|
|
1978 | |
|
|
1979 | $fh = IO::AIO::eventfd 0, IO::AIO::EFD_CLOEXEC |
|
|
1980 | or die "eventfd: $!\n"; |
|
|
1981 | |
|
|
1982 | $fh = IO::AIO::timerfd_create $clockid[, $flags] |
|
|
1983 | This is a direct interface to the Linux timerfd_create(2) system |
|
|
1984 | call. The (unhelpful) default for $flags is 0, but your default |
|
|
1985 | should be "IO::AIO::TFD_CLOEXEC". |
|
|
1986 | |
|
|
1987 | On success, the new timerfd filehandle is returned, otherwise |
|
|
1988 | returns "undef". If the timerfd_create syscall is missing, fails |
|
|
1989 | with "ENOSYS". |
|
|
1990 | |
|
|
1991 | Please refer to timerfd_create(2) for more info on this call. |
|
|
1992 | |
|
|
1993 | The following $clockid values are available: |
|
|
1994 | "IO::AIO::CLOCK_REALTIME", "IO::AIO::CLOCK_MONOTONIC" |
|
|
1995 | "IO::AIO::CLOCK_CLOCK_BOOTTIME" (Linux 3.15) |
|
|
1996 | "IO::AIO::CLOCK_CLOCK_REALTIME_ALARM" (Linux 3.11) and |
|
|
1997 | "IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM" (Linux 3.11). |
|
|
1998 | |
|
|
1999 | The following $flags values are available (Linux 2.6.27): |
|
|
2000 | "IO::AIO::TFD_NONBLOCK" and "IO::AIO::TFD_CLOEXEC". |
|
|
2001 | |
|
|
2002 | Example: create a new timerfd and set it to one-second repeated |
|
|
2003 | alarms, then wait for two alarms: |
|
|
2004 | |
|
|
2005 | my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC |
|
|
2006 | or die "timerfd_create: $!\n"; |
|
|
2007 | |
|
|
2008 | defined IO::AIO::timerfd_settime $fh, 0, 1, 1 |
|
|
2009 | or die "timerfd_settime: $!\n"; |
|
|
2010 | |
|
|
2011 | for (1..2) { |
|
|
2012 | 8 == sysread $fh, my $buf, 8 |
|
|
2013 | or die "timerfd read failure\n"; |
|
|
2014 | |
|
|
2015 | printf "number of expirations (likely 1): %d\n", |
|
|
2016 | unpack "Q", $buf; |
|
|
2017 | } |
|
|
2018 | |
|
|
2019 | ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, |
|
|
2020 | $new_interval, $nbw_value |
|
|
2021 | This is a direct interface to the Linux timerfd_settime(2) system |
|
|
2022 | call. Please refer to its manpage for more info on this call. |
|
|
2023 | |
|
|
2024 | The new itimerspec is specified using two (possibly fractional) |
|
|
2025 | second values, $new_interval and $new_value). |
|
|
2026 | |
|
|
2027 | On success, the current interval and value are returned (as per |
|
|
2028 | "timerfd_gettime"). On failure, the empty list is returned. |
|
|
2029 | |
|
|
2030 | The following $flags values are available: |
|
|
2031 | "IO::AIO::TFD_TIMER_ABSTIME" and "IO::AIO::TFD_TIMER_CANCEL_ON_SET". |
|
|
2032 | |
|
|
2033 | See "IO::AIO::timerfd_create" for a full example. |
|
|
2034 | |
|
|
2035 | ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh |
|
|
2036 | This is a direct interface to the Linux timerfd_gettime(2) system |
|
|
2037 | call. Please refer to its manpage for more info on this call. |
|
|
2038 | |
|
|
2039 | On success, returns the current values of interval and value for the |
|
|
2040 | given timerfd (as potentially fractional second values). On failure, |
|
|
2041 | the empty list is returned. |
|
|
2042 | |
|
|
2043 | EVENT LOOP INTEGRATION |
|
|
2044 | It is recommended to use AnyEvent::AIO to integrate IO::AIO |
|
|
2045 | automatically into many event loops: |
|
|
2046 | |
|
|
2047 | # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) |
|
|
2048 | use AnyEvent::AIO; |
|
|
2049 | |
|
|
2050 | You can also integrate IO::AIO manually into many event loops, here are |
|
|
2051 | some examples of how to do this: |
|
|
2052 | |
|
|
2053 | # EV integration |
|
|
2054 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
|
|
2055 | |
|
|
2056 | # Event integration |
|
|
2057 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
2058 | poll => 'r', |
|
|
2059 | cb => \&IO::AIO::poll_cb); |
|
|
2060 | |
|
|
2061 | # Glib/Gtk2 integration |
|
|
2062 | add_watch Glib::IO IO::AIO::poll_fileno, |
|
|
2063 | in => sub { IO::AIO::poll_cb; 1 }; |
|
|
2064 | |
|
|
2065 | # Tk integration |
|
|
2066 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
|
|
2067 | readable => \&IO::AIO::poll_cb); |
|
|
2068 | |
|
|
2069 | # Danga::Socket integration |
|
|
2070 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
|
|
2071 | \&IO::AIO::poll_cb); |
|
|
2072 | |
1026 | FORK BEHAVIOUR |
2073 | FORK BEHAVIOUR |
1027 | This module should do "the right thing" when the process using it forks: |
2074 | Usage of pthreads in a program changes the semantics of fork |
|
|
2075 | considerably. Specifically, only async-safe functions can be called |
|
|
2076 | after fork. Perl doesn't know about this, so in general, you cannot call |
|
|
2077 | fork with defined behaviour in perl if pthreads are involved. IO::AIO |
|
|
2078 | uses pthreads, so this applies, but many other extensions and (for |
|
|
2079 | inexplicable reasons) perl itself often is linked against pthreads, so |
|
|
2080 | this limitation applies to quite a lot of perls. |
1028 | |
2081 | |
1029 | Before the fork, IO::AIO enters a quiescent state where no requests can |
2082 | This module no longer tries to fight your OS, or POSIX. That means |
1030 | be added in other threads and no results will be processed. After the |
2083 | IO::AIO only works in the process that loaded it. Forking is fully |
1031 | fork the parent simply leaves the quiescent state and continues |
2084 | supported, but using IO::AIO in the child is not. |
1032 | request/result processing, while the child frees the request/result |
|
|
1033 | queue (so that the requests started before the fork will only be handled |
|
|
1034 | in the parent). Threads will be started on demand until the limit set in |
|
|
1035 | the parent process has been reached again. |
|
|
1036 | |
2085 | |
1037 | In short: the parent will, after a short pause, continue as if fork had |
2086 | You might get around by not *using* IO::AIO before (or after) forking. |
1038 | not been called, while the child will act as if IO::AIO has not been |
2087 | You could also try to call the IO::AIO::reinit function in the child: |
1039 | used yet. |
2088 | |
|
|
2089 | IO::AIO::reinit |
|
|
2090 | Abandons all current requests and I/O threads and simply |
|
|
2091 | reinitialises all data structures. This is not an operation |
|
|
2092 | supported by any standards, but happens to work on GNU/Linux and |
|
|
2093 | some newer BSD systems. |
|
|
2094 | |
|
|
2095 | The only reasonable use for this function is to call it after |
|
|
2096 | forking, if "IO::AIO" was used in the parent. Calling it while |
|
|
2097 | IO::AIO is active in the process will result in undefined behaviour. |
|
|
2098 | Calling it at any time will also result in any undefined (by POSIX) |
|
|
2099 | behaviour. |
|
|
2100 | |
|
|
2101 | LINUX-SPECIFIC CALLS |
|
|
2102 | When a call is documented as "linux-specific" then this means it |
|
|
2103 | originated on GNU/Linux. "IO::AIO" will usually try to autodetect the |
|
|
2104 | availability and compatibility of such calls regardless of the platform |
|
|
2105 | it is compiled on, so platforms such as FreeBSD which often implement |
|
|
2106 | these calls will work. When in doubt, call them and see if they fail wth |
|
|
2107 | "ENOSYS". |
1040 | |
2108 | |
1041 | MEMORY USAGE |
2109 | MEMORY USAGE |
1042 | Per-request usage: |
2110 | Per-request usage: |
1043 | |
2111 | |
1044 | Each aio request uses - depending on your architecture - around 100-200 |
2112 | Each aio request uses - depending on your architecture - around 100-200 |
… | |
… | |
1055 | In the execution phase, some aio requests require more memory for |
2123 | In the execution phase, some aio requests require more memory for |
1056 | temporary buffers, and each thread requires a stack and other data |
2124 | temporary buffers, and each thread requires a stack and other data |
1057 | structures (usually around 16k-128k, depending on the OS). |
2125 | structures (usually around 16k-128k, depending on the OS). |
1058 | |
2126 | |
1059 | KNOWN BUGS |
2127 | KNOWN BUGS |
1060 | Known bugs will be fixed in the next release. |
2128 | Known bugs will be fixed in the next release :) |
|
|
2129 | |
|
|
2130 | KNOWN ISSUES |
|
|
2131 | Calls that try to "import" foreign memory areas (such as "IO::AIO::mmap" |
|
|
2132 | or "IO::AIO::aio_slurp") do not work with generic lvalues, such as |
|
|
2133 | non-created hash slots or other scalars I didn't think of. It's best to |
|
|
2134 | avoid such and either use scalar variables or making sure that the |
|
|
2135 | scalar exists (e.g. by storing "undef") and isn't "funny" (e.g. tied). |
|
|
2136 | |
|
|
2137 | I am not sure anything can be done about this, so this is considered a |
|
|
2138 | known issue, rather than a bug. |
1061 | |
2139 | |
1062 | SEE ALSO |
2140 | SEE ALSO |
1063 | AnyEvent::AIO for easy integration into event loops, Coro::AIO for a |
2141 | AnyEvent::AIO for easy integration into event loops, Coro::AIO for a |
1064 | more natural syntax. |
2142 | more natural syntax. |
1065 | |
2143 | |