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2 | IO::AIO - Asynchronous Input/Output |
2 | IO::AIO - Asynchronous 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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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 | |
28 | |
29 | # AnyEvent integration |
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30 | open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; |
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31 | my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb }); |
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32 | |
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33 | # Event integration |
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34 | Event->io (fd => IO::AIO::poll_fileno, |
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35 | poll => 'r', |
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36 | cb => \&IO::AIO::poll_cb); |
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37 | |
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38 | # Glib/Gtk2 integration |
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39 | add_watch Glib::IO IO::AIO::poll_fileno, |
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40 | in => sub { IO::AIO::poll_cb; 1 }; |
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41 | |
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42 | # Tk integration |
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43 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
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44 | readable => \&IO::AIO::poll_cb); |
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45 | |
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46 | # Danga::Socket integration |
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47 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
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48 | \&IO::AIO::poll_cb); |
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49 | |
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50 | DESCRIPTION |
29 | DESCRIPTION |
51 | This module implements asynchronous I/O using whatever means your |
30 | This module implements asynchronous I/O using whatever means your |
52 | operating system supports. |
31 | operating system supports. It is implemented as an interface to "libeio" |
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32 | (<http://software.schmorp.de/pkg/libeio.html>). |
53 | |
33 | |
54 | Asynchronous means that operations that can normally block your program |
34 | Asynchronous means that operations that can normally block your program |
55 | (e.g. reading from disk) will be done asynchronously: the operation will |
35 | (e.g. reading from disk) will be done asynchronously: the operation will |
56 | still block, but you can do something else in the meantime. This is |
36 | still block, but you can do something else in the meantime. This is |
57 | extremely useful for programs that need to stay interactive even when |
37 | extremely useful for programs that need to stay interactive even when |
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62 | operations concurrently. |
42 | operations concurrently. |
63 | |
43 | |
64 | While most of this works on all types of file descriptors (for example |
44 | While most of this works on all types of file descriptors (for example |
65 | sockets), using these functions on file descriptors that support |
45 | sockets), using these functions on file descriptors that support |
66 | nonblocking operation (again, sockets, pipes etc.) is very inefficient. |
46 | nonblocking operation (again, sockets, pipes etc.) is very inefficient. |
67 | Use an event loop for that (such as the Event module): IO::AIO will |
47 | Use an event loop for that (such as the EV module): IO::AIO will |
68 | naturally fit into such an event loop itself. |
48 | naturally fit into such an event loop itself. |
69 | |
49 | |
70 | In this version, a number of threads are started that execute your |
50 | In this version, a number of threads are started that execute your |
71 | requests and signal their completion. You don't need thread support in |
51 | requests and signal their completion. You don't need thread support in |
72 | perl, and the threads created by this module will not be visible to |
52 | perl, and the threads created by this module will not be visible to |
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81 | it is currently not reentrant in any way, so use appropriate locking |
61 | it is currently not reentrant in any way, so use appropriate locking |
82 | yourself, always call "poll_cb" from within the same thread, or never |
62 | yourself, always call "poll_cb" from within the same thread, or never |
83 | call "poll_cb" (or other "aio_" functions) recursively. |
63 | call "poll_cb" (or other "aio_" functions) recursively. |
84 | |
64 | |
85 | EXAMPLE |
65 | EXAMPLE |
86 | This is a simple example that uses the Event module and loads |
66 | This is a simple example that uses the EV module and loads /etc/passwd |
87 | /etc/passwd asynchronously: |
67 | asynchronously: |
88 | |
68 | |
89 | use Fcntl; |
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90 | use Event; |
69 | use EV; |
91 | use IO::AIO; |
70 | use IO::AIO; |
92 | |
71 | |
93 | # register the IO::AIO callback with Event |
72 | # register the IO::AIO callback with EV |
94 | Event->io (fd => IO::AIO::poll_fileno, |
73 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
95 | poll => 'r', |
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96 | cb => \&IO::AIO::poll_cb); |
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97 | |
74 | |
98 | # queue the request to open /etc/passwd |
75 | # queue the request to open /etc/passwd |
99 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
76 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
100 | my $fh = shift |
77 | my $fh = shift |
101 | or die "error while opening: $!"; |
78 | or die "error while opening: $!"; |
102 | |
79 | |
103 | # stat'ing filehandles is generally non-blocking |
80 | # stat'ing filehandles is generally non-blocking |
104 | my $size = -s $fh; |
81 | my $size = -s $fh; |
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113 | |
90 | |
114 | # file contents now in $contents |
91 | # file contents now in $contents |
115 | print $contents; |
92 | print $contents; |
116 | |
93 | |
117 | # exit event loop and program |
94 | # exit event loop and program |
118 | Event::unloop; |
95 | EV::break; |
119 | }; |
96 | }; |
120 | }; |
97 | }; |
121 | |
98 | |
122 | # possibly queue up other requests, or open GUI windows, |
99 | # possibly queue up other requests, or open GUI windows, |
123 | # check for sockets etc. etc. |
100 | # check for sockets etc. etc. |
124 | |
101 | |
125 | # process events as long as there are some: |
102 | # process events as long as there are some: |
126 | Event::loop; |
103 | EV::run; |
127 | |
104 | |
128 | REQUEST ANATOMY AND LIFETIME |
105 | REQUEST ANATOMY AND LIFETIME |
129 | Every "aio_*" function creates a request. which is a C data structure |
106 | Every "aio_*" function creates a request. which is a C data structure |
130 | not directly visible to Perl. |
107 | not directly visible to Perl. |
131 | |
108 | |
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167 | anymore (except possibly for the Perl object, but its connection to |
144 | anymore (except possibly for the Perl object, but its connection to |
168 | the actual aio request is severed and calling its methods will |
145 | the actual aio request is severed and calling its methods will |
169 | either do nothing or result in a runtime error). |
146 | either do nothing or result in a runtime error). |
170 | |
147 | |
171 | FUNCTIONS |
148 | FUNCTIONS |
172 | AIO REQUEST FUNCTIONS |
149 | QUICK OVERVIEW |
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150 | This section simply lists the prototypes most of the functions for quick |
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151 | reference. See the following sections for function-by-function |
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152 | documentation. |
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153 | |
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154 | aio_wd $pathname, $callback->($wd) |
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155 | aio_open $pathname, $flags, $mode, $callback->($fh) |
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156 | aio_close $fh, $callback->($status) |
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157 | aio_seek $fh,$offset,$whence, $callback->($offs) |
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158 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
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159 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
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160 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
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161 | aio_readahead $fh,$offset,$length, $callback->($retval) |
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162 | aio_stat $fh_or_path, $callback->($status) |
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163 | aio_lstat $fh, $callback->($status) |
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164 | aio_statvfs $fh_or_path, $callback->($statvfs) |
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165 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
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166 | aio_chown $fh_or_path, $uid, $gid, $callback->($status) |
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167 | aio_chmod $fh_or_path, $mode, $callback->($status) |
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168 | aio_truncate $fh_or_path, $offset, $callback->($status) |
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169 | aio_allocate $fh, $mode, $offset, $len, $callback->($status) |
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170 | aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents) |
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171 | aio_unlink $pathname, $callback->($status) |
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172 | aio_mknod $pathname, $mode, $dev, $callback->($status) |
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173 | aio_link $srcpath, $dstpath, $callback->($status) |
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174 | aio_symlink $srcpath, $dstpath, $callback->($status) |
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175 | aio_readlink $pathname, $callback->($link) |
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176 | aio_realpath $pathname, $callback->($path) |
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177 | aio_rename $srcpath, $dstpath, $callback->($status) |
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178 | aio_mkdir $pathname, $mode, $callback->($status) |
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179 | aio_rmdir $pathname, $callback->($status) |
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180 | aio_readdir $pathname, $callback->($entries) |
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181 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
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182 | IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST |
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183 | IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN |
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184 | aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) |
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185 | aio_load $pathname, $data, $callback->($status) |
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186 | aio_copy $srcpath, $dstpath, $callback->($status) |
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187 | aio_move $srcpath, $dstpath, $callback->($status) |
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188 | aio_rmtree $pathname, $callback->($status) |
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189 | aio_fcntl $fh, $cmd, $arg, $callback->($status) |
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190 | aio_ioctl $fh, $request, $buf, $callback->($status) |
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191 | aio_sync $callback->($status) |
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192 | aio_syncfs $fh, $callback->($status) |
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193 | aio_fsync $fh, $callback->($status) |
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194 | aio_fdatasync $fh, $callback->($status) |
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195 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
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196 | aio_pathsync $pathname, $callback->($status) |
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197 | aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
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198 | aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
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199 | aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
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200 | aio_mlockall $flags, $callback->($status) |
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201 | aio_group $callback->(...) |
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202 | aio_nop $callback->() |
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203 | |
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204 | $prev_pri = aioreq_pri [$pri] |
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205 | aioreq_nice $pri_adjust |
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206 | |
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207 | IO::AIO::poll_wait |
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208 | IO::AIO::poll_cb |
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209 | IO::AIO::poll |
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210 | IO::AIO::flush |
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211 | IO::AIO::max_poll_reqs $nreqs |
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212 | IO::AIO::max_poll_time $seconds |
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213 | IO::AIO::min_parallel $nthreads |
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214 | IO::AIO::max_parallel $nthreads |
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215 | IO::AIO::max_idle $nthreads |
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216 | IO::AIO::idle_timeout $seconds |
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217 | IO::AIO::max_outstanding $maxreqs |
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218 | IO::AIO::nreqs |
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219 | IO::AIO::nready |
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220 | IO::AIO::npending |
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221 | |
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222 | IO::AIO::sendfile $ofh, $ifh, $offset, $count |
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223 | IO::AIO::fadvise $fh, $offset, $len, $advice |
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224 | IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] |
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225 | IO::AIO::munmap $scalar |
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226 | IO::AIO::madvise $scalar, $offset, $length, $advice |
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227 | IO::AIO::mprotect $scalar, $offset, $length, $protect |
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228 | IO::AIO::munlock $scalar, $offset = 0, $length = undef |
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229 | IO::AIO::munlockall |
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230 | |
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231 | API NOTES |
173 | All the "aio_*" calls are more or less thin wrappers around the syscall |
232 | All the "aio_*" calls are more or less thin wrappers around the syscall |
174 | with the same name (sans "aio_"). The arguments are similar or |
233 | with the same name (sans "aio_"). The arguments are similar or |
175 | identical, and they all accept an additional (and optional) $callback |
234 | identical, and they all accept an additional (and optional) $callback |
176 | argument which must be a code reference. This code reference will get |
235 | argument which must be a code reference. This code reference will be |
177 | called with the syscall return code (e.g. most syscalls return -1 on |
236 | called after the syscall has been executed in an asynchronous fashion. |
178 | error, unlike perl, which usually delivers "false") as it's sole |
237 | The results of the request will be passed as arguments to the callback |
179 | argument when the given syscall has been executed asynchronously. |
238 | (and, if an error occured, in $!) - for most requests the syscall return |
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239 | code (e.g. most syscalls return -1 on error, unlike perl, which usually |
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240 | delivers "false"). |
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241 | |
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242 | Some requests (such as "aio_readdir") pass the actual results and |
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243 | communicate failures by passing "undef". |
180 | |
244 | |
181 | All functions expecting a filehandle keep a copy of the filehandle |
245 | All functions expecting a filehandle keep a copy of the filehandle |
182 | internally until the request has finished. |
246 | internally until the request has finished. |
183 | |
247 | |
184 | All functions return request objects of type IO::AIO::REQ that allow |
248 | All functions return request objects of type IO::AIO::REQ that allow |
185 | further manipulation of those requests while they are in-flight. |
249 | further manipulation of those requests while they are in-flight. |
186 | |
250 | |
187 | The pathnames you pass to these routines *must* be absolute and encoded |
251 | The pathnames you pass to these routines *should* be absolute. The |
188 | as octets. The reason for the former is that at the time the request is |
252 | reason for this is that at the time the request is being executed, the |
189 | being executed, the current working directory could have changed. |
253 | current working directory could have changed. Alternatively, you can |
190 | Alternatively, you can make sure that you never change the current |
254 | make sure that you never change the current working directory anywhere |
191 | working directory anywhere in the program and then use relative paths. |
255 | in the program and then use relative paths. You can also take advantage |
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256 | of IO::AIOs working directory abstraction, that lets you specify paths |
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257 | relative to some previously-opened "working directory object" - see the |
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258 | description of the "IO::AIO::WD" class later in this document. |
192 | |
259 | |
193 | To encode pathnames as octets, either make sure you either: a) always |
260 | To encode pathnames as octets, either make sure you either: a) always |
194 | pass in filenames you got from outside (command line, readdir etc.) |
261 | pass in filenames you got from outside (command line, readdir etc.) |
195 | without tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module |
262 | without tinkering, b) are in your native filesystem encoding, c) use the |
196 | and encode your pathnames to the locale (or other) encoding in effect in |
263 | Encode module and encode your pathnames to the locale (or other) |
197 | the user environment, d) use Glib::filename_from_unicode on unicode |
264 | encoding in effect in the user environment, d) use |
198 | filenames or e) use something else to ensure your scalar has the correct |
265 | Glib::filename_from_unicode on unicode filenames or e) use something |
199 | contents. |
266 | else to ensure your scalar has the correct contents. |
200 | |
267 | |
201 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
268 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
202 | handles correctly wether it is set or not. |
269 | handles correctly whether it is set or not. |
203 | |
270 | |
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271 | AIO REQUEST FUNCTIONS |
204 | $prev_pri = aioreq_pri [$pri] |
272 | $prev_pri = aioreq_pri [$pri] |
205 | Returns the priority value that would be used for the next request |
273 | Returns the priority value that would be used for the next request |
206 | and, if $pri is given, sets the priority for the next aio request. |
274 | and, if $pri is given, sets the priority for the next aio request. |
207 | |
275 | |
208 | The default priority is 0, the minimum and maximum priorities are -4 |
276 | The default priority is 0, the minimum and maximum priorities are -4 |
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230 | Similar to "aioreq_pri", but subtracts the given value from the |
298 | Similar to "aioreq_pri", but subtracts the given value from the |
231 | current priority, so the effect is cumulative. |
299 | current priority, so the effect is cumulative. |
232 | |
300 | |
233 | aio_open $pathname, $flags, $mode, $callback->($fh) |
301 | aio_open $pathname, $flags, $mode, $callback->($fh) |
234 | Asynchronously open or create a file and call the callback with a |
302 | Asynchronously open or create a file and call the callback with a |
235 | newly created filehandle for the file. |
303 | newly created filehandle for the file (or "undef" in case of an |
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304 | error). |
236 | |
305 | |
237 | The pathname passed to "aio_open" must be absolute. See API NOTES, |
306 | The pathname passed to "aio_open" must be absolute. See API NOTES, |
238 | above, for an explanation. |
307 | above, for an explanation. |
239 | |
308 | |
240 | The $flags argument is a bitmask. See the "Fcntl" module for a list. |
309 | The $flags argument is a bitmask. See the "Fcntl" module for a list. |
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247 | will be modified by the umask in effect then the request is being |
316 | will be modified by the umask in effect then the request is being |
248 | executed, so better never change the umask. |
317 | executed, so better never change the umask. |
249 | |
318 | |
250 | Example: |
319 | Example: |
251 | |
320 | |
252 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
321 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
253 | if ($_[0]) { |
322 | if ($_[0]) { |
254 | print "open successful, fh is $_[0]\n"; |
323 | print "open successful, fh is $_[0]\n"; |
255 | ... |
324 | ... |
256 | } else { |
325 | } else { |
257 | die "open failed: $!\n"; |
326 | die "open failed: $!\n"; |
258 | } |
327 | } |
259 | }; |
328 | }; |
260 | |
329 | |
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330 | In addition to all the common open modes/flags ("O_RDONLY", |
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331 | "O_WRONLY", "O_RDWR", "O_CREAT", "O_TRUNC", "O_EXCL" and |
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332 | "O_APPEND"), the following POSIX and non-POSIX constants are |
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333 | available (missing ones on your system are, as usual, 0): |
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334 | |
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335 | "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY", |
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336 | "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY", |
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337 | "O_DSYNC", "O_RSYNC", "O_SYNC", "O_PATH", "O_TMPFILE", and |
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338 | "O_TTY_INIT". |
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339 | |
261 | aio_close $fh, $callback->($status) |
340 | aio_close $fh, $callback->($status) |
262 | Asynchronously close a file and call the callback with the result |
341 | Asynchronously close a file and call the callback with the result |
263 | code. |
342 | code. |
264 | |
343 | |
265 | Unfortunately, you can't do this to perl. Perl *insists* very |
344 | Unfortunately, you can't do this to perl. Perl *insists* very |
266 | strongly on closing the file descriptor associated with the |
345 | strongly on closing the file descriptor associated with the |
267 | filehandle itself. Here is what aio_close will try: |
346 | filehandle itself. |
268 | |
347 | |
269 | 1. dup()licate the fd |
348 | Therefore, "aio_close" will not close the filehandle - instead it |
270 | 2. asynchronously close() the duplicated fd |
349 | will use dup2 to overwrite the file descriptor with the write-end of |
271 | 3. dup()licate the fd once more |
350 | a pipe (the pipe fd will be created on demand and will be cached). |
272 | 4. let perl close() the filehandle |
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273 | 5. asynchronously close the duplicated fd |
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274 | |
351 | |
275 | The idea is that the first close() flushes stuff to disk that |
352 | Or in other words: the file descriptor will be closed, but it will |
276 | closing an fd will flush, so when perl closes the fd, nothing much |
353 | not be free for reuse until the perl filehandle is closed. |
277 | will need to be flushed. The second async. close() will then flush |
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278 | stuff to disk that closing the last fd to the file will flush. |
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279 | |
354 | |
280 | Just FYI, SuSv3 has this to say on close: |
355 | aio_seek $fh, $offset, $whence, $callback->($offs) |
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356 | Seeks the filehandle to the new $offset, similarly to perl's |
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357 | "sysseek". The $whence can use the traditional values (0 for |
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358 | "IO::AIO::SEEK_SET", 1 for "IO::AIO::SEEK_CUR" or 2 for |
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359 | "IO::AIO::SEEK_END"). |
281 | |
360 | |
282 | All outstanding record locks owned by the process on the file |
361 | The resulting absolute offset will be passed to the callback, or -1 |
283 | associated with the file descriptor shall be removed. |
362 | in case of an error. |
284 | |
363 | |
285 | If fildes refers to a socket, close() shall cause the socket to be |
364 | In theory, the $whence constants could be different than the |
286 | destroyed. ... close() shall block for up to the current linger |
365 | corresponding values from Fcntl, but perl guarantees they are the |
287 | interval until all data is transmitted. |
366 | same, so don't panic. |
288 | [this actually sounds like a specification bug, but who knows] |
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289 | |
367 | |
290 | And at least Linux additionally actually flushes stuff on every |
368 | As a GNU/Linux (and maybe Solaris) extension, also the constants |
291 | close, even when the file itself is still open. |
369 | "IO::AIO::SEEK_DATA" and "IO::AIO::SEEK_HOLE" are available, if they |
292 | |
370 | could be found. No guarantees about suitability for use in |
293 | Sounds enourmously inefficient and complicated? Yes... please show |
371 | "aio_seek" or Perl's "sysseek" can be made though, although I would |
294 | me how to nuke perl's fd out of existence... |
372 | naively assume they "just work". |
295 | |
373 | |
296 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
374 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
297 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
375 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
298 | Reads or writes $length bytes from the specified $fh and $offset |
376 | Reads or writes $length bytes from or to the specified $fh and |
299 | into the scalar given by $data and offset $dataoffset and calls the |
377 | $offset into the scalar given by $data and offset $dataoffset and |
300 | callback without the actual number of bytes read (or -1 on error, |
378 | calls the callback without the actual number of bytes read (or -1 on |
301 | just like the syscall). |
379 | error, just like the syscall). |
|
|
380 | |
|
|
381 | "aio_read" will, like "sysread", shrink or grow the $data scalar to |
|
|
382 | offset plus the actual number of bytes read. |
302 | |
383 | |
303 | If $offset is undefined, then the current file descriptor offset |
384 | If $offset is undefined, then the current file descriptor offset |
304 | will be used (and updated), otherwise the file descriptor offset |
385 | will be used (and updated), otherwise the file descriptor offset |
305 | will not be changed by these calls. |
386 | will not be changed by these calls. |
306 | |
387 | |
… | |
… | |
325 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
406 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
326 | Tries to copy $length bytes from $in_fh to $out_fh. It starts |
407 | Tries to copy $length bytes from $in_fh to $out_fh. It starts |
327 | reading at byte offset $in_offset, and starts writing at the current |
408 | reading at byte offset $in_offset, and starts writing at the current |
328 | file offset of $out_fh. Because of that, it is not safe to issue |
409 | file offset of $out_fh. Because of that, it is not safe to issue |
329 | more than one "aio_sendfile" per $out_fh, as they will interfere |
410 | more than one "aio_sendfile" per $out_fh, as they will interfere |
330 | with each other. |
411 | with each other. The same $in_fh works fine though, as this function |
|
|
412 | does not move or use the file offset of $in_fh. |
331 | |
413 | |
|
|
414 | Please note that "aio_sendfile" can read more bytes from $in_fh than |
|
|
415 | are written, and there is no way to find out how many more bytes |
|
|
416 | have been read from "aio_sendfile" alone, as "aio_sendfile" only |
|
|
417 | provides the number of bytes written to $out_fh. Only if the result |
|
|
418 | value equals $length one can assume that $length bytes have been |
|
|
419 | read. |
|
|
420 | |
|
|
421 | Unlike with other "aio_" functions, it makes a lot of sense to use |
|
|
422 | "aio_sendfile" on non-blocking sockets, as long as one end |
|
|
423 | (typically the $in_fh) is a file - the file I/O will then be |
|
|
424 | asynchronous, while the socket I/O will be non-blocking. Note, |
|
|
425 | however, that you can run into a trap where "aio_sendfile" reads |
|
|
426 | some data with readahead, then fails to write all data, and when the |
|
|
427 | socket is ready the next time, the data in the cache is already |
|
|
428 | lost, forcing "aio_sendfile" to again hit the disk. Explicit |
|
|
429 | "aio_read" + "aio_write" let's you better control resource usage. |
|
|
430 | |
332 | This call tries to make use of a native "sendfile" syscall to |
431 | This call tries to make use of a native "sendfile"-like syscall to |
333 | provide zero-copy operation. For this to work, $out_fh should refer |
432 | provide zero-copy operation. For this to work, $out_fh should refer |
334 | to a socket, and $in_fh should refer to mmap'able file. |
433 | to a socket, and $in_fh should refer to an mmap'able file. |
335 | |
434 | |
336 | If the native sendfile call fails or is not implemented, it will be |
435 | If a native sendfile cannot be found or it fails with "ENOSYS", |
337 | emulated, so you can call "aio_sendfile" on any type of filehandle |
436 | "EINVAL", "ENOTSUP", "EOPNOTSUPP", "EAFNOSUPPORT", "EPROTOTYPE" or |
338 | regardless of the limitations of the operating system. |
437 | "ENOTSOCK", it will be emulated, so you can call "aio_sendfile" on |
|
|
438 | any type of filehandle regardless of the limitations of the |
|
|
439 | operating system. |
339 | |
440 | |
340 | Please note, however, that "aio_sendfile" can read more bytes from |
441 | As native sendfile syscalls (as practically any non-POSIX interface |
341 | $in_fh than are written, and there is no way to find out how many |
442 | hacked together in a hurry to improve benchmark numbers) tend to be |
342 | bytes have been read from "aio_sendfile" alone, as "aio_sendfile" |
443 | rather buggy on many systems, this implementation tries to work |
343 | only provides the number of bytes written to $out_fh. Only if the |
444 | around some known bugs in Linux and FreeBSD kernels (probably |
344 | result value equals $length one can assume that $length bytes have |
445 | others, too), but that might fail, so you really really should check |
345 | been read. |
446 | the return value of "aio_sendfile" - fewre bytes than expected might |
|
|
447 | have been transferred. |
346 | |
448 | |
347 | aio_readahead $fh,$offset,$length, $callback->($retval) |
449 | aio_readahead $fh,$offset,$length, $callback->($retval) |
348 | "aio_readahead" populates the page cache with data from a file so |
450 | "aio_readahead" populates the page cache with data from a file so |
349 | that subsequent reads from that file will not block on disk I/O. The |
451 | that subsequent reads from that file will not block on disk I/O. The |
350 | $offset argument specifies the starting point from which data is to |
452 | $offset argument specifies the starting point from which data is to |
… | |
… | |
371 | Currently, the stats are always 64-bit-stats, i.e. instead of |
473 | Currently, the stats are always 64-bit-stats, i.e. instead of |
372 | returning an error when stat'ing a large file, the results will be |
474 | returning an error when stat'ing a large file, the results will be |
373 | silently truncated unless perl itself is compiled with large file |
475 | silently truncated unless perl itself is compiled with large file |
374 | support. |
476 | support. |
375 | |
477 | |
|
|
478 | To help interpret the mode and dev/rdev stat values, IO::AIO offers |
|
|
479 | the following constants and functions (if not implemented, the |
|
|
480 | constants will be 0 and the functions will either "croak" or fall |
|
|
481 | back on traditional behaviour). |
|
|
482 | |
|
|
483 | "S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG", |
|
|
484 | "S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t", |
|
|
485 | "IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor". |
|
|
486 | |
376 | Example: Print the length of /etc/passwd: |
487 | Example: Print the length of /etc/passwd: |
377 | |
488 | |
378 | aio_stat "/etc/passwd", sub { |
489 | aio_stat "/etc/passwd", sub { |
379 | $_[0] and die "stat failed: $!"; |
490 | $_[0] and die "stat failed: $!"; |
380 | print "size is ", -s _, "\n"; |
491 | print "size is ", -s _, "\n"; |
381 | }; |
492 | }; |
382 | |
493 | |
|
|
494 | aio_statvfs $fh_or_path, $callback->($statvfs) |
|
|
495 | Works like the POSIX "statvfs" or "fstatvfs" syscalls, depending on |
|
|
496 | whether a file handle or path was passed. |
|
|
497 | |
|
|
498 | On success, the callback is passed a hash reference with the |
|
|
499 | following members: "bsize", "frsize", "blocks", "bfree", "bavail", |
|
|
500 | "files", "ffree", "favail", "fsid", "flag" and "namemax". On |
|
|
501 | failure, "undef" is passed. |
|
|
502 | |
|
|
503 | The following POSIX IO::AIO::ST_* constants are defined: "ST_RDONLY" |
|
|
504 | and "ST_NOSUID". |
|
|
505 | |
|
|
506 | The following non-POSIX IO::AIO::ST_* flag masks are defined to |
|
|
507 | their correct value when available, or to 0 on systems that do not |
|
|
508 | support them: "ST_NODEV", "ST_NOEXEC", "ST_SYNCHRONOUS", |
|
|
509 | "ST_MANDLOCK", "ST_WRITE", "ST_APPEND", "ST_IMMUTABLE", |
|
|
510 | "ST_NOATIME", "ST_NODIRATIME" and "ST_RELATIME". |
|
|
511 | |
|
|
512 | Example: stat "/wd" and dump out the data if successful. |
|
|
513 | |
|
|
514 | aio_statvfs "/wd", sub { |
|
|
515 | my $f = $_[0] |
|
|
516 | or die "statvfs: $!"; |
|
|
517 | |
|
|
518 | use Data::Dumper; |
|
|
519 | say Dumper $f; |
|
|
520 | }; |
|
|
521 | |
|
|
522 | # result: |
|
|
523 | { |
|
|
524 | bsize => 1024, |
|
|
525 | bfree => 4333064312, |
|
|
526 | blocks => 10253828096, |
|
|
527 | files => 2050765568, |
|
|
528 | flag => 4096, |
|
|
529 | favail => 2042092649, |
|
|
530 | bavail => 4333064312, |
|
|
531 | ffree => 2042092649, |
|
|
532 | namemax => 255, |
|
|
533 | frsize => 1024, |
|
|
534 | fsid => 1810 |
|
|
535 | } |
|
|
536 | |
|
|
537 | Here is a (likely partial - send me updates!) list of fsid values |
|
|
538 | used by Linux - it is safe to hardcode these when $^O is "linux": |
|
|
539 | |
|
|
540 | 0x0000adf5 adfs |
|
|
541 | 0x0000adff affs |
|
|
542 | 0x5346414f afs |
|
|
543 | 0x09041934 anon-inode filesystem |
|
|
544 | 0x00000187 autofs |
|
|
545 | 0x42465331 befs |
|
|
546 | 0x1badface bfs |
|
|
547 | 0x42494e4d binfmt_misc |
|
|
548 | 0x9123683e btrfs |
|
|
549 | 0x0027e0eb cgroupfs |
|
|
550 | 0xff534d42 cifs |
|
|
551 | 0x73757245 coda |
|
|
552 | 0x012ff7b7 coh |
|
|
553 | 0x28cd3d45 cramfs |
|
|
554 | 0x453dcd28 cramfs-wend (wrong endianness) |
|
|
555 | 0x64626720 debugfs |
|
|
556 | 0x00001373 devfs |
|
|
557 | 0x00001cd1 devpts |
|
|
558 | 0x0000f15f ecryptfs |
|
|
559 | 0x00414a53 efs |
|
|
560 | 0x0000137d ext |
|
|
561 | 0x0000ef53 ext2/ext3/ext4 |
|
|
562 | 0x0000ef51 ext2 |
|
|
563 | 0xf2f52010 f2fs |
|
|
564 | 0x00004006 fat |
|
|
565 | 0x65735546 fuseblk |
|
|
566 | 0x65735543 fusectl |
|
|
567 | 0x0bad1dea futexfs |
|
|
568 | 0x01161970 gfs2 |
|
|
569 | 0x47504653 gpfs |
|
|
570 | 0x00004244 hfs |
|
|
571 | 0xf995e849 hpfs |
|
|
572 | 0x00c0ffee hostfs |
|
|
573 | 0x958458f6 hugetlbfs |
|
|
574 | 0x2bad1dea inotifyfs |
|
|
575 | 0x00009660 isofs |
|
|
576 | 0x000072b6 jffs2 |
|
|
577 | 0x3153464a jfs |
|
|
578 | 0x6b414653 k-afs |
|
|
579 | 0x0bd00bd0 lustre |
|
|
580 | 0x0000137f minix |
|
|
581 | 0x0000138f minix 30 char names |
|
|
582 | 0x00002468 minix v2 |
|
|
583 | 0x00002478 minix v2 30 char names |
|
|
584 | 0x00004d5a minix v3 |
|
|
585 | 0x19800202 mqueue |
|
|
586 | 0x00004d44 msdos |
|
|
587 | 0x0000564c novell |
|
|
588 | 0x00006969 nfs |
|
|
589 | 0x6e667364 nfsd |
|
|
590 | 0x00003434 nilfs |
|
|
591 | 0x5346544e ntfs |
|
|
592 | 0x00009fa1 openprom |
|
|
593 | 0x7461636F ocfs2 |
|
|
594 | 0x00009fa0 proc |
|
|
595 | 0x6165676c pstorefs |
|
|
596 | 0x0000002f qnx4 |
|
|
597 | 0x68191122 qnx6 |
|
|
598 | 0x858458f6 ramfs |
|
|
599 | 0x52654973 reiserfs |
|
|
600 | 0x00007275 romfs |
|
|
601 | 0x67596969 rpc_pipefs |
|
|
602 | 0x73636673 securityfs |
|
|
603 | 0xf97cff8c selinux |
|
|
604 | 0x0000517b smb |
|
|
605 | 0x534f434b sockfs |
|
|
606 | 0x73717368 squashfs |
|
|
607 | 0x62656572 sysfs |
|
|
608 | 0x012ff7b6 sysv2 |
|
|
609 | 0x012ff7b5 sysv4 |
|
|
610 | 0x01021994 tmpfs |
|
|
611 | 0x15013346 udf |
|
|
612 | 0x00011954 ufs |
|
|
613 | 0x54190100 ufs byteswapped |
|
|
614 | 0x00009fa2 usbdevfs |
|
|
615 | 0x01021997 v9fs |
|
|
616 | 0xa501fcf5 vxfs |
|
|
617 | 0xabba1974 xenfs |
|
|
618 | 0x012ff7b4 xenix |
|
|
619 | 0x58465342 xfs |
|
|
620 | 0x012fd16d xia |
|
|
621 | |
383 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
622 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
384 | Works like perl's "utime" function (including the special case of |
623 | Works like perl's "utime" function (including the special case of |
385 | $atime and $mtime being undef). Fractional times are supported if |
624 | $atime and $mtime being undef). Fractional times are supported if |
386 | the underlying syscalls support them. |
625 | the underlying syscalls support them. |
387 | |
626 | |
… | |
… | |
409 | aio_chown "path", 0, undef; |
648 | aio_chown "path", 0, undef; |
410 | |
649 | |
411 | aio_truncate $fh_or_path, $offset, $callback->($status) |
650 | aio_truncate $fh_or_path, $offset, $callback->($status) |
412 | Works like truncate(2) or ftruncate(2). |
651 | Works like truncate(2) or ftruncate(2). |
413 | |
652 | |
|
|
653 | aio_allocate $fh, $mode, $offset, $len, $callback->($status) |
|
|
654 | Allocates or frees disk space according to the $mode argument. See |
|
|
655 | the linux "fallocate" documentation for details. |
|
|
656 | |
|
|
657 | $mode is usually 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to allocate |
|
|
658 | space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE | |
|
|
659 | IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range. |
|
|
660 | |
|
|
661 | IO::AIO also supports "FALLOC_FL_COLLAPSE_RANGE", to remove a range |
|
|
662 | (without leaving a hole) and "FALLOC_FL_ZERO_RANGE", to zero a range |
|
|
663 | (see your fallocate(2) manpage). |
|
|
664 | |
|
|
665 | The file system block size used by "fallocate" is presumably the |
|
|
666 | "f_bsize" returned by "statvfs". |
|
|
667 | |
|
|
668 | If "fallocate" isn't available or cannot be emulated (currently no |
|
|
669 | emulation will be attempted), passes -1 and sets $! to "ENOSYS". |
|
|
670 | |
414 | aio_chmod $fh_or_path, $mode, $callback->($status) |
671 | aio_chmod $fh_or_path, $mode, $callback->($status) |
415 | Works like perl's "chmod" function. |
672 | Works like perl's "chmod" function. |
416 | |
673 | |
417 | aio_unlink $pathname, $callback->($status) |
674 | aio_unlink $pathname, $callback->($status) |
418 | Asynchronously unlink (delete) a file and call the callback with the |
675 | Asynchronously unlink (delete) a file and call the callback with the |
419 | result code. |
676 | result code. |
420 | |
677 | |
421 | aio_mknod $path, $mode, $dev, $callback->($status) |
678 | aio_mknod $pathname, $mode, $dev, $callback->($status) |
422 | [EXPERIMENTAL] |
679 | [EXPERIMENTAL] |
423 | |
680 | |
424 | Asynchronously create a device node (or fifo). See mknod(2). |
681 | Asynchronously create a device node (or fifo). See mknod(2). |
425 | |
682 | |
426 | The only (POSIX-) portable way of calling this function is: |
683 | The only (POSIX-) portable way of calling this function is: |
427 | |
684 | |
428 | aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
685 | aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
|
|
686 | |
|
|
687 | See "aio_stat" for info about some potentially helpful extra |
|
|
688 | constants and functions. |
429 | |
689 | |
430 | aio_link $srcpath, $dstpath, $callback->($status) |
690 | aio_link $srcpath, $dstpath, $callback->($status) |
431 | Asynchronously create a new link to the existing object at $srcpath |
691 | Asynchronously create a new link to the existing object at $srcpath |
432 | at the path $dstpath and call the callback with the result code. |
692 | at the path $dstpath and call the callback with the result code. |
433 | |
693 | |
434 | aio_symlink $srcpath, $dstpath, $callback->($status) |
694 | aio_symlink $srcpath, $dstpath, $callback->($status) |
435 | Asynchronously create a new symbolic link to the existing object at |
695 | Asynchronously create a new symbolic link to the existing object at |
436 | $srcpath at the path $dstpath and call the callback with the result |
696 | $srcpath at the path $dstpath and call the callback with the result |
437 | code. |
697 | code. |
438 | |
698 | |
439 | aio_readlink $path, $callback->($link) |
699 | aio_readlink $pathname, $callback->($link) |
440 | Asynchronously read the symlink specified by $path and pass it to |
700 | Asynchronously read the symlink specified by $path and pass it to |
441 | the callback. If an error occurs, nothing or undef gets passed to |
701 | the callback. If an error occurs, nothing or undef gets passed to |
442 | the callback. |
702 | the callback. |
443 | |
703 | |
|
|
704 | aio_realpath $pathname, $callback->($path) |
|
|
705 | Asynchronously make the path absolute and resolve any symlinks in |
|
|
706 | $path. The resulting path only consists of directories (same as |
|
|
707 | Cwd::realpath). |
|
|
708 | |
|
|
709 | This request can be used to get the absolute path of the current |
|
|
710 | working directory by passing it a path of . (a single dot). |
|
|
711 | |
444 | aio_rename $srcpath, $dstpath, $callback->($status) |
712 | aio_rename $srcpath, $dstpath, $callback->($status) |
445 | Asynchronously rename the object at $srcpath to $dstpath, just as |
713 | Asynchronously rename the object at $srcpath to $dstpath, just as |
446 | rename(2) and call the callback with the result code. |
714 | rename(2) and call the callback with the result code. |
|
|
715 | |
|
|
716 | On systems that support the AIO::WD working directory abstraction |
|
|
717 | natively, the case "[$wd, "."]" as $srcpath is specialcased - |
|
|
718 | instead of failing, "rename" is called on the absolute path of $wd. |
447 | |
719 | |
448 | aio_mkdir $pathname, $mode, $callback->($status) |
720 | aio_mkdir $pathname, $mode, $callback->($status) |
449 | Asynchronously mkdir (create) a directory and call the callback with |
721 | Asynchronously mkdir (create) a directory and call the callback with |
450 | the result code. $mode will be modified by the umask at the time the |
722 | the result code. $mode will be modified by the umask at the time the |
451 | request is executed, so do not change your umask. |
723 | request is executed, so do not change your umask. |
452 | |
724 | |
453 | aio_rmdir $pathname, $callback->($status) |
725 | aio_rmdir $pathname, $callback->($status) |
454 | Asynchronously rmdir (delete) a directory and call the callback with |
726 | Asynchronously rmdir (delete) a directory and call the callback with |
455 | the result code. |
727 | the result code. |
456 | |
728 | |
|
|
729 | On systems that support the AIO::WD working directory abstraction |
|
|
730 | natively, the case "[$wd, "."]" is specialcased - instead of |
|
|
731 | failing, "rmdir" is called on the absolute path of $wd. |
|
|
732 | |
457 | aio_readdir $pathname, $callback->($entries) |
733 | aio_readdir $pathname, $callback->($entries) |
458 | Unlike the POSIX call of the same name, "aio_readdir" reads an |
734 | Unlike the POSIX call of the same name, "aio_readdir" reads an |
459 | entire directory (i.e. opendir + readdir + closedir). The entries |
735 | entire directory (i.e. opendir + readdir + closedir). The entries |
460 | will not be sorted, and will NOT include the "." and ".." entries. |
736 | will not be sorted, and will NOT include the "." and ".." entries. |
461 | |
737 | |
462 | The callback a single argument which is either "undef" or an |
738 | The callback is passed a single argument which is either "undef" or |
463 | array-ref with the filenames. |
739 | an array-ref with the filenames. |
464 | |
740 | |
|
|
741 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
|
|
742 | Quite similar to "aio_readdir", but the $flags argument allows one |
|
|
743 | to tune behaviour and output format. In case of an error, $entries |
|
|
744 | will be "undef". |
|
|
745 | |
|
|
746 | The flags are a combination of the following constants, ORed |
|
|
747 | together (the flags will also be passed to the callback, possibly |
|
|
748 | modified): |
|
|
749 | |
|
|
750 | IO::AIO::READDIR_DENTS |
|
|
751 | When this flag is off, then the callback gets an arrayref |
|
|
752 | consisting of names only (as with "aio_readdir"), otherwise it |
|
|
753 | gets an arrayref with "[$name, $type, $inode]" arrayrefs, each |
|
|
754 | describing a single directory entry in more detail. |
|
|
755 | |
|
|
756 | $name is the name of the entry. |
|
|
757 | |
|
|
758 | $type is one of the "IO::AIO::DT_xxx" constants: |
|
|
759 | |
|
|
760 | "IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR", |
|
|
761 | "IO::AIO::DT_DIR", "IO::AIO::DT_BLK", "IO::AIO::DT_REG", |
|
|
762 | "IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT". |
|
|
763 | |
|
|
764 | "IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If |
|
|
765 | you need to know, you have to run stat yourself. Also, for speed |
|
|
766 | reasons, the $type scalars are read-only: you can not modify |
|
|
767 | them. |
|
|
768 | |
|
|
769 | $inode is the inode number (which might not be exact on systems |
|
|
770 | with 64 bit inode numbers and 32 bit perls). This field has |
|
|
771 | unspecified content on systems that do not deliver the inode |
|
|
772 | information. |
|
|
773 | |
|
|
774 | IO::AIO::READDIR_DIRS_FIRST |
|
|
775 | When this flag is set, then the names will be returned in an |
|
|
776 | order where likely directories come first, in optimal stat |
|
|
777 | order. This is useful when you need to quickly find directories, |
|
|
778 | or you want to find all directories while avoiding to stat() |
|
|
779 | each entry. |
|
|
780 | |
|
|
781 | If the system returns type information in readdir, then this is |
|
|
782 | used to find directories directly. Otherwise, likely directories |
|
|
783 | are names beginning with ".", or otherwise names with no dots, |
|
|
784 | of which names with short names are tried first. |
|
|
785 | |
|
|
786 | IO::AIO::READDIR_STAT_ORDER |
|
|
787 | When this flag is set, then the names will be returned in an |
|
|
788 | order suitable for stat()'ing each one. That is, when you plan |
|
|
789 | to stat() all files in the given directory, then the returned |
|
|
790 | order will likely be fastest. |
|
|
791 | |
|
|
792 | If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are |
|
|
793 | specified, then the likely dirs come first, resulting in a less |
|
|
794 | optimal stat order. |
|
|
795 | |
|
|
796 | IO::AIO::READDIR_FOUND_UNKNOWN |
|
|
797 | This flag should not be set when calling "aio_readdirx". |
|
|
798 | Instead, it is being set by "aio_readdirx", when any of the |
|
|
799 | $type's found were "IO::AIO::DT_UNKNOWN". The absence of this |
|
|
800 | flag therefore indicates that all $type's are known, which can |
|
|
801 | be used to speed up some algorithms. |
|
|
802 | |
465 | aio_load $path, $data, $callback->($status) |
803 | aio_load $pathname, $data, $callback->($status) |
466 | This is a composite request that tries to fully load the given file |
804 | This is a composite request that tries to fully load the given file |
467 | into memory. Status is the same as with aio_read. |
805 | into memory. Status is the same as with aio_read. |
468 | |
806 | |
469 | aio_copy $srcpath, $dstpath, $callback->($status) |
807 | aio_copy $srcpath, $dstpath, $callback->($status) |
470 | Try to copy the *file* (directories not supported as either source |
808 | Try to copy the *file* (directories not supported as either source |
471 | or destination) from $srcpath to $dstpath and call the callback with |
809 | or destination) from $srcpath to $dstpath and call the callback with |
472 | the 0 (error) or -1 ok. |
810 | a status of 0 (ok) or -1 (error, see $!). |
473 | |
811 | |
474 | This is a composite request that it creates the destination file |
812 | This is a composite request that creates the destination file with |
475 | with mode 0200 and copies the contents of the source file into it |
813 | mode 0200 and copies the contents of the source file into it using |
476 | using "aio_sendfile", followed by restoring atime, mtime, access |
814 | "aio_sendfile", followed by restoring atime, mtime, access mode and |
477 | mode and uid/gid, in that order. |
815 | uid/gid, in that order. |
478 | |
816 | |
479 | If an error occurs, the partial destination file will be unlinked, |
817 | If an error occurs, the partial destination file will be unlinked, |
480 | if possible, except when setting atime, mtime, access mode and |
818 | if possible, except when setting atime, mtime, access mode and |
481 | uid/gid, where errors are being ignored. |
819 | uid/gid, where errors are being ignored. |
482 | |
820 | |
483 | aio_move $srcpath, $dstpath, $callback->($status) |
821 | aio_move $srcpath, $dstpath, $callback->($status) |
484 | Try to move the *file* (directories not supported as either source |
822 | Try to move the *file* (directories not supported as either source |
485 | or destination) from $srcpath to $dstpath and call the callback with |
823 | or destination) from $srcpath to $dstpath and call the callback with |
486 | the 0 (error) or -1 ok. |
824 | a status of 0 (ok) or -1 (error, see $!). |
487 | |
825 | |
488 | This is a composite request that tries to rename(2) the file first. |
826 | This is a composite request that tries to rename(2) the file first; |
489 | If rename files with "EXDEV", it copies the file with "aio_copy" |
827 | if rename fails with "EXDEV", it copies the file with "aio_copy" |
490 | and, if that is successful, unlinking the $srcpath. |
828 | and, if that is successful, unlinks the $srcpath. |
491 | |
829 | |
492 | aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
830 | aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) |
493 | Scans a directory (similar to "aio_readdir") but additionally tries |
831 | Scans a directory (similar to "aio_readdir") but additionally tries |
494 | to efficiently separate the entries of directory $path into two sets |
832 | to efficiently separate the entries of directory $path into two sets |
495 | of names, directories you can recurse into (directories), and ones |
833 | of names, directories you can recurse into (directories), and ones |
496 | you cannot recurse into (everything else, including symlinks to |
834 | you cannot recurse into (everything else, including symlinks to |
497 | directories). |
835 | directories). |
… | |
… | |
515 | Implementation notes. |
853 | Implementation notes. |
516 | |
854 | |
517 | The "aio_readdir" cannot be avoided, but "stat()"'ing every entry |
855 | The "aio_readdir" cannot be avoided, but "stat()"'ing every entry |
518 | can. |
856 | can. |
519 | |
857 | |
|
|
858 | If readdir returns file type information, then this is used directly |
|
|
859 | to find directories. |
|
|
860 | |
520 | After reading the directory, the modification time, size etc. of the |
861 | Otherwise, after reading the directory, the modification time, size |
521 | directory before and after the readdir is checked, and if they match |
862 | etc. of the directory before and after the readdir is checked, and |
522 | (and isn't the current time), the link count will be used to decide |
863 | if they match (and isn't the current time), the link count will be |
523 | how many entries are directories (if >= 2). Otherwise, no knowledge |
864 | used to decide how many entries are directories (if >= 2). |
524 | of the number of subdirectories will be assumed. |
865 | Otherwise, no knowledge of the number of subdirectories will be |
|
|
866 | assumed. |
525 | |
867 | |
526 | Then entries will be sorted into likely directories (everything |
868 | Then entries will be sorted into likely directories a non-initial |
527 | without a non-initial dot currently) and likely non-directories |
869 | dot currently) and likely non-directories (see "aio_readdirx"). Then |
528 | (everything else). Then every entry plus an appended "/." will be |
870 | every entry plus an appended "/." will be "stat"'ed, likely |
529 | "stat"'ed, likely directories first. If that succeeds, it assumes |
871 | directories first, in order of their inode numbers. If that |
530 | that the entry is a directory or a symlink to directory (which will |
872 | succeeds, it assumes that the entry is a directory or a symlink to |
531 | be checked seperately). This is often faster than stat'ing the entry |
873 | directory (which will be checked separately). This is often faster |
532 | itself because filesystems might detect the type of the entry |
874 | than stat'ing the entry itself because filesystems might detect the |
533 | without reading the inode data (e.g. ext2fs filetype feature). |
875 | type of the entry without reading the inode data (e.g. ext2fs |
|
|
876 | filetype feature), even on systems that cannot return the filetype |
|
|
877 | information on readdir. |
534 | |
878 | |
535 | If the known number of directories (link count - 2) has been |
879 | If the known number of directories (link count - 2) has been |
536 | reached, the rest of the entries is assumed to be non-directories. |
880 | reached, the rest of the entries is assumed to be non-directories. |
537 | |
881 | |
538 | This only works with certainty on POSIX (= UNIX) filesystems, which |
882 | This only works with certainty on POSIX (= UNIX) filesystems, which |
… | |
… | |
540 | |
884 | |
541 | It will also likely work on non-POSIX filesystems with reduced |
885 | It will also likely work on non-POSIX filesystems with reduced |
542 | efficiency as those tend to return 0 or 1 as link counts, which |
886 | efficiency as those tend to return 0 or 1 as link counts, which |
543 | disables the directory counting heuristic. |
887 | disables the directory counting heuristic. |
544 | |
888 | |
545 | aio_rmtree $path, $callback->($status) |
889 | aio_rmtree $pathname, $callback->($status) |
546 | Delete a directory tree starting (and including) $path, return the |
890 | Delete a directory tree starting (and including) $path, return the |
547 | status of the final "rmdir" only. This is a composite request that |
891 | status of the final "rmdir" only. This is a composite request that |
548 | uses "aio_scandir" to recurse into and rmdir directories, and unlink |
892 | uses "aio_scandir" to recurse into and rmdir directories, and unlink |
549 | everything else. |
893 | everything else. |
550 | |
894 | |
|
|
895 | aio_fcntl $fh, $cmd, $arg, $callback->($status) |
|
|
896 | aio_ioctl $fh, $request, $buf, $callback->($status) |
|
|
897 | These work just like the "fcntl" and "ioctl" built-in functions, |
|
|
898 | except they execute asynchronously and pass the return value to the |
|
|
899 | callback. |
|
|
900 | |
|
|
901 | Both calls can be used for a lot of things, some of which make more |
|
|
902 | sense to run asynchronously in their own thread, while some others |
|
|
903 | make less sense. For example, calls that block waiting for external |
|
|
904 | events, such as locking, will also lock down an I/O thread while it |
|
|
905 | is waiting, which can deadlock the whole I/O system. At the same |
|
|
906 | time, there might be no alternative to using a thread to wait. |
|
|
907 | |
|
|
908 | So in general, you should only use these calls for things that do |
|
|
909 | (filesystem) I/O, not for things that wait for other events |
|
|
910 | (network, other processes), although if you are careful and know |
|
|
911 | what you are doing, you still can. |
|
|
912 | |
|
|
913 | aio_sync $callback->($status) |
|
|
914 | Asynchronously call sync and call the callback when finished. |
|
|
915 | |
551 | aio_fsync $fh, $callback->($status) |
916 | aio_fsync $fh, $callback->($status) |
552 | Asynchronously call fsync on the given filehandle and call the |
917 | Asynchronously call fsync on the given filehandle and call the |
553 | callback with the fsync result code. |
918 | callback with the fsync result code. |
554 | |
919 | |
555 | aio_fdatasync $fh, $callback->($status) |
920 | aio_fdatasync $fh, $callback->($status) |
556 | Asynchronously call fdatasync on the given filehandle and call the |
921 | Asynchronously call fdatasync on the given filehandle and call the |
557 | callback with the fdatasync result code. |
922 | callback with the fdatasync result code. |
558 | |
923 | |
559 | If this call isn't available because your OS lacks it or it couldn't |
924 | If this call isn't available because your OS lacks it or it couldn't |
560 | be detected, it will be emulated by calling "fsync" instead. |
925 | be detected, it will be emulated by calling "fsync" instead. |
|
|
926 | |
|
|
927 | aio_syncfs $fh, $callback->($status) |
|
|
928 | Asynchronously call the syncfs syscall to sync the filesystem |
|
|
929 | associated to the given filehandle and call the callback with the |
|
|
930 | syncfs result code. If syncfs is not available, calls sync(), but |
|
|
931 | returns -1 and sets errno to "ENOSYS" nevertheless. |
|
|
932 | |
|
|
933 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
|
|
934 | Sync the data portion of the file specified by $offset and $length |
|
|
935 | to disk (but NOT the metadata), by calling the Linux-specific |
|
|
936 | sync_file_range call. If sync_file_range is not available or it |
|
|
937 | returns ENOSYS, then fdatasync or fsync is being substituted. |
|
|
938 | |
|
|
939 | $flags can be a combination of |
|
|
940 | "IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE", |
|
|
941 | "IO::AIO::SYNC_FILE_RANGE_WRITE" and |
|
|
942 | "IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER": refer to the sync_file_range |
|
|
943 | manpage for details. |
|
|
944 | |
|
|
945 | aio_pathsync $pathname, $callback->($status) |
|
|
946 | This request tries to open, fsync and close the given path. This is |
|
|
947 | a composite request intended to sync directories after directory |
|
|
948 | operations (E.g. rename). This might not work on all operating |
|
|
949 | systems or have any specific effect, but usually it makes sure that |
|
|
950 | directory changes get written to disc. It works for anything that |
|
|
951 | can be opened for read-only, not just directories. |
|
|
952 | |
|
|
953 | Future versions of this function might fall back to other methods |
|
|
954 | when "fsync" on the directory fails (such as calling "sync"). |
|
|
955 | |
|
|
956 | Passes 0 when everything went ok, and -1 on error. |
|
|
957 | |
|
|
958 | aio_msync $scalar, $offset = 0, $length = undef, flags = 0, |
|
|
959 | $callback->($status) |
|
|
960 | This is a rather advanced IO::AIO call, which only works on |
|
|
961 | mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it |
|
|
962 | also works on data scalars managed by the Sys::Mmap or Mmap modules, |
|
|
963 | note that the scalar must only be modified in-place while an aio |
|
|
964 | operation is pending on it). |
|
|
965 | |
|
|
966 | It calls the "msync" function of your OS, if available, with the |
|
|
967 | memory area starting at $offset in the string and ending $length |
|
|
968 | bytes later. If $length is negative, counts from the end, and if |
|
|
969 | $length is "undef", then it goes till the end of the string. The |
|
|
970 | flags can be a combination of "IO::AIO::MS_ASYNC", |
|
|
971 | "IO::AIO::MS_INVALIDATE" and "IO::AIO::MS_SYNC". |
|
|
972 | |
|
|
973 | aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, |
|
|
974 | $callback->($status) |
|
|
975 | This is a rather advanced IO::AIO call, which works best on |
|
|
976 | mmap(2)ed scalars. |
|
|
977 | |
|
|
978 | It touches (reads or writes) all memory pages in the specified range |
|
|
979 | inside the scalar. All caveats and parameters are the same as for |
|
|
980 | "aio_msync", above, except for flags, which must be either 0 (which |
|
|
981 | reads all pages and ensures they are instantiated) or |
|
|
982 | "IO::AIO::MT_MODIFY", which modifies the memory pages (by reading |
|
|
983 | and writing an octet from it, which dirties the page). |
|
|
984 | |
|
|
985 | aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
|
|
986 | This is a rather advanced IO::AIO call, which works best on |
|
|
987 | mmap(2)ed scalars. |
|
|
988 | |
|
|
989 | It reads in all the pages of the underlying storage into memory (if |
|
|
990 | any) and locks them, so they are not getting swapped/paged out or |
|
|
991 | removed. |
|
|
992 | |
|
|
993 | If $length is undefined, then the scalar will be locked till the |
|
|
994 | end. |
|
|
995 | |
|
|
996 | On systems that do not implement "mlock", this function returns -1 |
|
|
997 | and sets errno to "ENOSYS". |
|
|
998 | |
|
|
999 | Note that the corresponding "munlock" is synchronous and is |
|
|
1000 | documented under "MISCELLANEOUS FUNCTIONS". |
|
|
1001 | |
|
|
1002 | Example: open a file, mmap and mlock it - both will be undone when |
|
|
1003 | $data gets destroyed. |
|
|
1004 | |
|
|
1005 | open my $fh, "<", $path or die "$path: $!"; |
|
|
1006 | my $data; |
|
|
1007 | IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; |
|
|
1008 | aio_mlock $data; # mlock in background |
|
|
1009 | |
|
|
1010 | aio_mlockall $flags, $callback->($status) |
|
|
1011 | Calls the "mlockall" function with the given $flags (a combination |
|
|
1012 | of "IO::AIO::MCL_CURRENT" and "IO::AIO::MCL_FUTURE"). |
|
|
1013 | |
|
|
1014 | On systems that do not implement "mlockall", this function returns |
|
|
1015 | -1 and sets errno to "ENOSYS". |
|
|
1016 | |
|
|
1017 | Note that the corresponding "munlockall" is synchronous and is |
|
|
1018 | documented under "MISCELLANEOUS FUNCTIONS". |
|
|
1019 | |
|
|
1020 | Example: asynchronously lock all current and future pages into |
|
|
1021 | memory. |
|
|
1022 | |
|
|
1023 | aio_mlockall IO::AIO::MCL_FUTURE; |
|
|
1024 | |
|
|
1025 | aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents) |
|
|
1026 | Queries the extents of the given file (by calling the Linux "FIEMAP" |
|
|
1027 | ioctl, see <http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for |
|
|
1028 | details). If the ioctl is not available on your OS, then this |
|
|
1029 | request will fail with "ENOSYS". |
|
|
1030 | |
|
|
1031 | $start is the starting offset to query extents for, $length is the |
|
|
1032 | size of the range to query - if it is "undef", then the whole file |
|
|
1033 | will be queried. |
|
|
1034 | |
|
|
1035 | $flags is a combination of flags ("IO::AIO::FIEMAP_FLAG_SYNC" or |
|
|
1036 | "IO::AIO::FIEMAP_FLAG_XATTR" - "IO::AIO::FIEMAP_FLAGS_COMPAT" is |
|
|
1037 | also exported), and is normally 0 or "IO::AIO::FIEMAP_FLAG_SYNC" to |
|
|
1038 | query the data portion. |
|
|
1039 | |
|
|
1040 | $count is the maximum number of extent records to return. If it is |
|
|
1041 | "undef", then IO::AIO queries all extents of the range. As a very |
|
|
1042 | special case, if it is 0, then the callback receives the number of |
|
|
1043 | extents instead of the extents themselves (which is unreliable, see |
|
|
1044 | below). |
|
|
1045 | |
|
|
1046 | If an error occurs, the callback receives no arguments. The special |
|
|
1047 | "errno" value "IO::AIO::EBADR" is available to test for flag errors. |
|
|
1048 | |
|
|
1049 | Otherwise, the callback receives an array reference with extent |
|
|
1050 | structures. Each extent structure is an array reference itself, with |
|
|
1051 | the following members: |
|
|
1052 | |
|
|
1053 | [$logical, $physical, $length, $flags] |
|
|
1054 | |
|
|
1055 | Flags is any combination of the following flag values (typically |
|
|
1056 | either 0 or "IO::AIO::FIEMAP_EXTENT_LAST" (1)): |
|
|
1057 | |
|
|
1058 | "IO::AIO::FIEMAP_EXTENT_LAST", "IO::AIO::FIEMAP_EXTENT_UNKNOWN", |
|
|
1059 | "IO::AIO::FIEMAP_EXTENT_DELALLOC", "IO::AIO::FIEMAP_EXTENT_ENCODED", |
|
|
1060 | "IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED", |
|
|
1061 | "IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED", |
|
|
1062 | "IO::AIO::FIEMAP_EXTENT_DATA_INLINE", |
|
|
1063 | "IO::AIO::FIEMAP_EXTENT_DATA_TAIL", |
|
|
1064 | "IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED" |
|
|
1065 | or "IO::AIO::FIEMAP_EXTENT_SHARED". |
|
|
1066 | |
|
|
1067 | At the time of this writing (Linux 3.2), this requets is unreliable |
|
|
1068 | unless $count is "undef", as the kernel has all sorts of bugs |
|
|
1069 | preventing it to return all extents of a range for files with large |
|
|
1070 | number of extents. The code works around all these issues if $count |
|
|
1071 | is undef. |
561 | |
1072 | |
562 | aio_group $callback->(...) |
1073 | aio_group $callback->(...) |
563 | This is a very special aio request: Instead of doing something, it |
1074 | This is a very special aio request: Instead of doing something, it |
564 | is a container for other aio requests, which is useful if you want |
1075 | is a container for other aio requests, which is useful if you want |
565 | to bundle many requests into a single, composite, request with a |
1076 | to bundle many requests into a single, composite, request with a |
… | |
… | |
600 | requests like sleep and file handle readable/writable, the overhead |
1111 | requests like sleep and file handle readable/writable, the overhead |
601 | this creates is immense (it blocks a thread for a long time) so do |
1112 | this creates is immense (it blocks a thread for a long time) so do |
602 | not use this function except to put your application under |
1113 | not use this function except to put your application under |
603 | artificial I/O pressure. |
1114 | artificial I/O pressure. |
604 | |
1115 | |
|
|
1116 | IO::AIO::WD - multiple working directories |
|
|
1117 | Your process only has one current working directory, which is used by |
|
|
1118 | all threads. This makes it hard to use relative paths (some other |
|
|
1119 | component could call "chdir" at any time, and it is hard to control when |
|
|
1120 | the path will be used by IO::AIO). |
|
|
1121 | |
|
|
1122 | One solution for this is to always use absolute paths. This usually |
|
|
1123 | works, but can be quite slow (the kernel has to walk the whole path on |
|
|
1124 | every access), and can also be a hassle to implement. |
|
|
1125 | |
|
|
1126 | Newer POSIX systems have a number of functions (openat, fdopendir, |
|
|
1127 | futimensat and so on) that make it possible to specify working |
|
|
1128 | directories per operation. |
|
|
1129 | |
|
|
1130 | For portability, and because the clowns who "designed", or shall I |
|
|
1131 | write, perpetrated this new interface were obviously half-drunk, this |
|
|
1132 | abstraction cannot be perfect, though. |
|
|
1133 | |
|
|
1134 | IO::AIO allows you to convert directory paths into a so-called |
|
|
1135 | IO::AIO::WD object. This object stores the canonicalised, absolute |
|
|
1136 | version of the path, and on systems that allow it, also a directory file |
|
|
1137 | descriptor. |
|
|
1138 | |
|
|
1139 | Everywhere where a pathname is accepted by IO::AIO (e.g. in "aio_stat" |
|
|
1140 | or "aio_unlink"), one can specify an array reference with an IO::AIO::WD |
|
|
1141 | object and a pathname instead (or the IO::AIO::WD object alone, which |
|
|
1142 | gets interpreted as "[$wd, "."]"). If the pathname is absolute, the |
|
|
1143 | IO::AIO::WD object is ignored, otherwise the pathname is resolved |
|
|
1144 | relative to that IO::AIO::WD object. |
|
|
1145 | |
|
|
1146 | For example, to get a wd object for /etc and then stat passwd inside, |
|
|
1147 | you would write: |
|
|
1148 | |
|
|
1149 | aio_wd "/etc", sub { |
|
|
1150 | my $etcdir = shift; |
|
|
1151 | |
|
|
1152 | # although $etcdir can be undef on error, there is generally no reason |
|
|
1153 | # to check for errors here, as aio_stat will fail with ENOENT |
|
|
1154 | # when $etcdir is undef. |
|
|
1155 | |
|
|
1156 | aio_stat [$etcdir, "passwd"], sub { |
|
|
1157 | # yay |
|
|
1158 | }; |
|
|
1159 | }; |
|
|
1160 | |
|
|
1161 | The fact that "aio_wd" is a request and not a normal function shows that |
|
|
1162 | creating an IO::AIO::WD object is itself a potentially blocking |
|
|
1163 | operation, which is why it is done asynchronously. |
|
|
1164 | |
|
|
1165 | To stat the directory obtained with "aio_wd" above, one could write |
|
|
1166 | either of the following three request calls: |
|
|
1167 | |
|
|
1168 | aio_lstat "/etc" , sub { ... # pathname as normal string |
|
|
1169 | aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself) |
|
|
1170 | aio_lstat $wd , sub { ... # shorthand for the previous |
|
|
1171 | |
|
|
1172 | As with normal pathnames, IO::AIO keeps a copy of the working directory |
|
|
1173 | object and the pathname string, so you could write the following without |
|
|
1174 | causing any issues due to $path getting reused: |
|
|
1175 | |
|
|
1176 | my $path = [$wd, undef]; |
|
|
1177 | |
|
|
1178 | for my $name (qw(abc def ghi)) { |
|
|
1179 | $path->[1] = $name; |
|
|
1180 | aio_stat $path, sub { |
|
|
1181 | # ... |
|
|
1182 | }; |
|
|
1183 | } |
|
|
1184 | |
|
|
1185 | There are some caveats: when directories get renamed (or deleted), the |
|
|
1186 | pathname string doesn't change, so will point to the new directory (or |
|
|
1187 | nowhere at all), while the directory fd, if available on the system, |
|
|
1188 | will still point to the original directory. Most functions accepting a |
|
|
1189 | pathname will use the directory fd on newer systems, and the string on |
|
|
1190 | older systems. Some functions (such as realpath) will always rely on the |
|
|
1191 | string form of the pathname. |
|
|
1192 | |
|
|
1193 | So this functionality is mainly useful to get some protection against |
|
|
1194 | "chdir", to easily get an absolute path out of a relative path for |
|
|
1195 | future reference, and to speed up doing many operations in the same |
|
|
1196 | directory (e.g. when stat'ing all files in a directory). |
|
|
1197 | |
|
|
1198 | The following functions implement this working directory abstraction: |
|
|
1199 | |
|
|
1200 | aio_wd $pathname, $callback->($wd) |
|
|
1201 | Asynchonously canonicalise the given pathname and convert it to an |
|
|
1202 | IO::AIO::WD object representing it. If possible and supported on the |
|
|
1203 | system, also open a directory fd to speed up pathname resolution |
|
|
1204 | relative to this working directory. |
|
|
1205 | |
|
|
1206 | If something goes wrong, then "undef" is passwd to the callback |
|
|
1207 | instead of a working directory object and $! is set appropriately. |
|
|
1208 | Since passing "undef" as working directory component of a pathname |
|
|
1209 | fails the request with "ENOENT", there is often no need for error |
|
|
1210 | checking in the "aio_wd" callback, as future requests using the |
|
|
1211 | value will fail in the expected way. |
|
|
1212 | |
|
|
1213 | IO::AIO::CWD |
|
|
1214 | This is a compiletime constant (object) that represents the process |
|
|
1215 | current working directory. |
|
|
1216 | |
|
|
1217 | Specifying this object as working directory object for a pathname is |
|
|
1218 | as if the pathname would be specified directly, without a directory |
|
|
1219 | object. For example, these calls are functionally identical: |
|
|
1220 | |
|
|
1221 | aio_stat "somefile", sub { ... }; |
|
|
1222 | aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; |
|
|
1223 | |
|
|
1224 | To recover the path associated with an IO::AIO::WD object, you can use |
|
|
1225 | "aio_realpath": |
|
|
1226 | |
|
|
1227 | aio_realpath $wd, sub { |
|
|
1228 | warn "path is $_[0]\n"; |
|
|
1229 | }; |
|
|
1230 | |
|
|
1231 | Currently, "aio_statvfs" always, and "aio_rename" and "aio_rmdir" |
|
|
1232 | sometimes, fall back to using an absolue path. |
|
|
1233 | |
605 | IO::AIO::REQ CLASS |
1234 | IO::AIO::REQ CLASS |
606 | All non-aggregate "aio_*" functions return an object of this class when |
1235 | All non-aggregate "aio_*" functions return an object of this class when |
607 | called in non-void context. |
1236 | called in non-void context. |
608 | |
1237 | |
609 | cancel $req |
1238 | cancel $req |
610 | Cancels the request, if possible. Has the effect of skipping |
1239 | Cancels the request, if possible. Has the effect of skipping |
611 | execution when entering the execute state and skipping calling the |
1240 | execution when entering the execute state and skipping calling the |
612 | callback when entering the the result state, but will leave the |
1241 | callback when entering the the result state, but will leave the |
613 | request otherwise untouched. That means that requests that currently |
1242 | request otherwise untouched (with the exception of readdir). That |
614 | execute will not be stopped and resources held by the request will |
1243 | means that requests that currently execute will not be stopped and |
615 | not be freed prematurely. |
1244 | resources held by the request will not be freed prematurely. |
616 | |
1245 | |
617 | cb $req $callback->(...) |
1246 | cb $req $callback->(...) |
618 | Replace (or simply set) the callback registered to the request. |
1247 | Replace (or simply set) the callback registered to the request. |
619 | |
1248 | |
620 | IO::AIO::GRP CLASS |
1249 | IO::AIO::GRP CLASS |
… | |
… | |
647 | }; |
1276 | }; |
648 | |
1277 | |
649 | This makes it very easy to create composite requests (see the source of |
1278 | This makes it very easy to create composite requests (see the source of |
650 | "aio_move" for an application) that work and feel like simple requests. |
1279 | "aio_move" for an application) that work and feel like simple requests. |
651 | |
1280 | |
652 | * The IO::AIO::GRP objects will be cleaned up during calls to |
1281 | * The IO::AIO::GRP objects will be cleaned up during calls to |
653 | "IO::AIO::poll_cb", just like any other request. |
1282 | "IO::AIO::poll_cb", just like any other request. |
|
|
1283 | |
654 | * They can be canceled like any other request. Canceling will cancel not |
1284 | * They can be canceled like any other request. Canceling will cancel |
655 | only the request itself, but also all requests it contains. |
1285 | not only the request itself, but also all requests it contains. |
|
|
1286 | |
656 | * They can also can also be added to other IO::AIO::GRP objects. |
1287 | * They can also can also be added to other IO::AIO::GRP objects. |
|
|
1288 | |
657 | * You must not add requests to a group from within the group callback |
1289 | * You must not add requests to a group from within the group callback |
658 | (or any later time). |
1290 | (or any later time). |
659 | |
1291 | |
660 | Their lifetime, simplified, looks like this: when they are empty, they |
1292 | Their lifetime, simplified, looks like this: when they are empty, they |
661 | will finish very quickly. If they contain only requests that are in the |
1293 | will finish very quickly. If they contain only requests that are in the |
662 | "done" state, they will also finish. Otherwise they will continue to |
1294 | "done" state, they will also finish. Otherwise they will continue to |
663 | exist. |
1295 | exist. |
664 | |
1296 | |
665 | That means after creating a group you have some time to add requests. |
1297 | That means after creating a group you have some time to add requests |
666 | And in the callbacks of those requests, you can add further requests to |
1298 | (precisely before the callback has been invoked, which is only done |
667 | the group. And only when all those requests have finished will the the |
1299 | within the "poll_cb"). And in the callbacks of those requests, you can |
668 | group itself finish. |
1300 | add further requests to the group. And only when all those requests have |
|
|
1301 | finished will the the group itself finish. |
669 | |
1302 | |
670 | add $grp ... |
1303 | add $grp ... |
671 | $grp->add (...) |
1304 | $grp->add (...) |
672 | Add one or more requests to the group. Any type of IO::AIO::REQ can |
1305 | Add one or more requests to the group. Any type of IO::AIO::REQ can |
673 | be added, including other groups, as long as you do not create |
1306 | be added, including other groups, as long as you do not create |
… | |
… | |
678 | $grp->cancel_subs |
1311 | $grp->cancel_subs |
679 | Cancel all subrequests and clears any feeder, but not the group |
1312 | Cancel all subrequests and clears any feeder, but not the group |
680 | request itself. Useful when you queued a lot of events but got a |
1313 | request itself. Useful when you queued a lot of events but got a |
681 | result early. |
1314 | result early. |
682 | |
1315 | |
|
|
1316 | The group request will finish normally (you cannot add requests to |
|
|
1317 | the group). |
|
|
1318 | |
683 | $grp->result (...) |
1319 | $grp->result (...) |
684 | Set the result value(s) that will be passed to the group callback |
1320 | Set the result value(s) that will be passed to the group callback |
685 | when all subrequests have finished and set thre groups errno to the |
1321 | when all subrequests have finished and set the groups errno to the |
686 | current value of errno (just like calling "errno" without an error |
1322 | current value of errno (just like calling "errno" without an error |
687 | number). By default, no argument will be passed and errno is zero. |
1323 | number). By default, no argument will be passed and errno is zero. |
688 | |
1324 | |
689 | $grp->errno ([$errno]) |
1325 | $grp->errno ([$errno]) |
690 | Sets the group errno value to $errno, or the current value of errno |
1326 | Sets the group errno value to $errno, or the current value of errno |
… | |
… | |
701 | Sets a feeder/generator on this group: every group can have an |
1337 | Sets a feeder/generator on this group: every group can have an |
702 | attached generator that generates requests if idle. The idea behind |
1338 | attached generator that generates requests if idle. The idea behind |
703 | this is that, although you could just queue as many requests as you |
1339 | this is that, although you could just queue as many requests as you |
704 | want in a group, this might starve other requests for a potentially |
1340 | want in a group, this might starve other requests for a potentially |
705 | long time. For example, "aio_scandir" might generate hundreds of |
1341 | long time. For example, "aio_scandir" might generate hundreds of |
706 | thousands "aio_stat" requests, delaying any later requests for a |
1342 | thousands of "aio_stat" requests, delaying any later requests for a |
707 | long time. |
1343 | long time. |
708 | |
1344 | |
709 | To avoid this, and allow incremental generation of requests, you can |
1345 | To avoid this, and allow incremental generation of requests, you can |
710 | instead a group and set a feeder on it that generates those |
1346 | instead a group and set a feeder on it that generates those |
711 | requests. The feed callback will be called whenever there are few |
1347 | requests. The feed callback will be called whenever there are few |
… | |
… | |
716 | does not impose any limits). |
1352 | does not impose any limits). |
717 | |
1353 | |
718 | If the feed does not queue more requests when called, it will be |
1354 | If the feed does not queue more requests when called, it will be |
719 | automatically removed from the group. |
1355 | automatically removed from the group. |
720 | |
1356 | |
721 | If the feed limit is 0, it will be set to 2 automatically. |
1357 | If the feed limit is 0 when this method is called, it will be set to |
|
|
1358 | 2 automatically. |
722 | |
1359 | |
723 | Example: |
1360 | Example: |
724 | |
1361 | |
725 | # stat all files in @files, but only ever use four aio requests concurrently: |
1362 | # stat all files in @files, but only ever use four aio requests concurrently: |
726 | |
1363 | |
… | |
… | |
737 | Sets the feeder limit for the group: The feeder will be called |
1374 | Sets the feeder limit for the group: The feeder will be called |
738 | whenever the group contains less than this many requests. |
1375 | whenever the group contains less than this many requests. |
739 | |
1376 | |
740 | Setting the limit to 0 will pause the feeding process. |
1377 | Setting the limit to 0 will pause the feeding process. |
741 | |
1378 | |
|
|
1379 | The default value for the limit is 0, but note that setting a feeder |
|
|
1380 | automatically bumps it up to 2. |
|
|
1381 | |
742 | SUPPORT FUNCTIONS |
1382 | SUPPORT FUNCTIONS |
743 | EVENT PROCESSING AND EVENT LOOP INTEGRATION |
1383 | EVENT PROCESSING AND EVENT LOOP INTEGRATION |
744 | $fileno = IO::AIO::poll_fileno |
1384 | $fileno = IO::AIO::poll_fileno |
745 | Return the *request result pipe file descriptor*. This filehandle |
1385 | Return the *request result pipe file descriptor*. This filehandle |
746 | must be polled for reading by some mechanism outside this module |
1386 | must be polled for reading by some mechanism outside this module |
747 | (e.g. Event or select, see below or the SYNOPSIS). If the pipe |
1387 | (e.g. EV, Glib, select and so on, see below or the SYNOPSIS). If the |
748 | becomes readable you have to call "poll_cb" to check the results. |
1388 | pipe becomes readable you have to call "poll_cb" to check the |
|
|
1389 | results. |
749 | |
1390 | |
750 | See "poll_cb" for an example. |
1391 | See "poll_cb" for an example. |
751 | |
1392 | |
752 | IO::AIO::poll_cb |
1393 | IO::AIO::poll_cb |
753 | Process some outstanding events on the result pipe. You have to call |
1394 | Process some requests that have reached the result phase (i.e. they |
754 | this regularly. Returns the number of events processed. Returns |
1395 | have been executed but the results are not yet reported). You have |
|
|
1396 | to call this "regularly" to finish outstanding requests. |
|
|
1397 | |
|
|
1398 | Returns 0 if all events could be processed (or there were no events |
|
|
1399 | to process), or -1 if it returned earlier for whatever reason. |
755 | immediately when no events are outstanding. The amount of events |
1400 | Returns immediately when no events are outstanding. The amount of |
756 | processed depends on the settings of "IO::AIO::max_poll_req" and |
1401 | events processed depends on the settings of "IO::AIO::max_poll_req", |
757 | "IO::AIO::max_poll_time". |
1402 | "IO::AIO::max_poll_time" and "IO::AIO::max_outstanding". |
758 | |
1403 | |
759 | If not all requests were processed for whatever reason, the |
1404 | If not all requests were processed for whatever reason, the poll |
760 | filehandle will still be ready when "poll_cb" returns. |
1405 | file descriptor will still be ready when "poll_cb" returns, so |
|
|
1406 | normally you don't have to do anything special to have it called |
|
|
1407 | later. |
|
|
1408 | |
|
|
1409 | Apart from calling "IO::AIO::poll_cb" when the event filehandle |
|
|
1410 | becomes ready, it can be beneficial to call this function from loops |
|
|
1411 | which submit a lot of requests, to make sure the results get |
|
|
1412 | processed when they become available and not just when the loop is |
|
|
1413 | finished and the event loop takes over again. This function returns |
|
|
1414 | very fast when there are no outstanding requests. |
761 | |
1415 | |
762 | Example: Install an Event watcher that automatically calls |
1416 | Example: Install an Event watcher that automatically calls |
763 | IO::AIO::poll_cb with high priority: |
1417 | IO::AIO::poll_cb with high priority (more examples can be found in |
|
|
1418 | the SYNOPSIS section, at the top of this document): |
764 | |
1419 | |
765 | Event->io (fd => IO::AIO::poll_fileno, |
1420 | Event->io (fd => IO::AIO::poll_fileno, |
766 | poll => 'r', async => 1, |
1421 | poll => 'r', async => 1, |
767 | cb => \&IO::AIO::poll_cb); |
1422 | cb => \&IO::AIO::poll_cb); |
|
|
1423 | |
|
|
1424 | IO::AIO::poll_wait |
|
|
1425 | Wait until either at least one request is in the result phase or no |
|
|
1426 | requests are outstanding anymore. |
|
|
1427 | |
|
|
1428 | This is useful if you want to synchronously wait for some requests |
|
|
1429 | to become ready, without actually handling them. |
|
|
1430 | |
|
|
1431 | See "nreqs" for an example. |
|
|
1432 | |
|
|
1433 | IO::AIO::poll |
|
|
1434 | Waits until some requests have been handled. |
|
|
1435 | |
|
|
1436 | Returns the number of requests processed, but is otherwise strictly |
|
|
1437 | equivalent to: |
|
|
1438 | |
|
|
1439 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1440 | |
|
|
1441 | IO::AIO::flush |
|
|
1442 | Wait till all outstanding AIO requests have been handled. |
|
|
1443 | |
|
|
1444 | Strictly equivalent to: |
|
|
1445 | |
|
|
1446 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1447 | while IO::AIO::nreqs; |
768 | |
1448 | |
769 | IO::AIO::max_poll_reqs $nreqs |
1449 | IO::AIO::max_poll_reqs $nreqs |
770 | IO::AIO::max_poll_time $seconds |
1450 | IO::AIO::max_poll_time $seconds |
771 | These set the maximum number of requests (default 0, meaning |
1451 | These set the maximum number of requests (default 0, meaning |
772 | infinity) that are being processed by "IO::AIO::poll_cb" in one |
1452 | infinity) that are being processed by "IO::AIO::poll_cb" in one |
… | |
… | |
796 | # use a low priority so other tasks have priority |
1476 | # use a low priority so other tasks have priority |
797 | Event->io (fd => IO::AIO::poll_fileno, |
1477 | Event->io (fd => IO::AIO::poll_fileno, |
798 | poll => 'r', nice => 1, |
1478 | poll => 'r', nice => 1, |
799 | cb => &IO::AIO::poll_cb); |
1479 | cb => &IO::AIO::poll_cb); |
800 | |
1480 | |
801 | IO::AIO::poll_wait |
|
|
802 | If there are any outstanding requests and none of them in the result |
|
|
803 | phase, wait till the result filehandle becomes ready for reading |
|
|
804 | (simply does a "select" on the filehandle. This is useful if you |
|
|
805 | want to synchronously wait for some requests to finish). |
|
|
806 | |
|
|
807 | See "nreqs" for an example. |
|
|
808 | |
|
|
809 | IO::AIO::poll |
|
|
810 | Waits until some requests have been handled. |
|
|
811 | |
|
|
812 | Returns the number of requests processed, but is otherwise strictly |
|
|
813 | equivalent to: |
|
|
814 | |
|
|
815 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
816 | |
|
|
817 | IO::AIO::flush |
|
|
818 | Wait till all outstanding AIO requests have been handled. |
|
|
819 | |
|
|
820 | Strictly equivalent to: |
|
|
821 | |
|
|
822 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
823 | while IO::AIO::nreqs; |
|
|
824 | |
|
|
825 | CONTROLLING THE NUMBER OF THREADS |
1481 | CONTROLLING THE NUMBER OF THREADS |
826 | IO::AIO::min_parallel $nthreads |
1482 | IO::AIO::min_parallel $nthreads |
827 | Set the minimum number of AIO threads to $nthreads. The current |
1483 | Set the minimum number of AIO threads to $nthreads. The current |
828 | default is 8, which means eight asynchronous operations can execute |
1484 | default is 8, which means eight asynchronous operations can execute |
829 | concurrently at any one time (the number of outstanding requests, |
1485 | concurrently at any one time (the number of outstanding requests, |
… | |
… | |
858 | |
1514 | |
859 | Under normal circumstances you don't need to call this function. |
1515 | Under normal circumstances you don't need to call this function. |
860 | |
1516 | |
861 | IO::AIO::max_idle $nthreads |
1517 | IO::AIO::max_idle $nthreads |
862 | Limit the number of threads (default: 4) that are allowed to idle |
1518 | Limit the number of threads (default: 4) that are allowed to idle |
863 | (i.e., threads that did not get a request to process within 10 |
1519 | (i.e., threads that did not get a request to process within the idle |
864 | seconds). That means if a thread becomes idle while $nthreads other |
1520 | timeout (default: 10 seconds). That means if a thread becomes idle |
865 | threads are also idle, it will free its resources and exit. |
1521 | while $nthreads other threads are also idle, it will free its |
|
|
1522 | resources and exit. |
866 | |
1523 | |
867 | This is useful when you allow a large number of threads (e.g. 100 or |
1524 | This is useful when you allow a large number of threads (e.g. 100 or |
868 | 1000) to allow for extremely high load situations, but want to free |
1525 | 1000) to allow for extremely high load situations, but want to free |
869 | resources under normal circumstances (1000 threads can easily |
1526 | resources under normal circumstances (1000 threads can easily |
870 | consume 30MB of RAM). |
1527 | consume 30MB of RAM). |
871 | |
1528 | |
872 | The default is probably ok in most situations, especially if thread |
1529 | The default is probably ok in most situations, especially if thread |
873 | creation is fast. If thread creation is very slow on your system you |
1530 | creation is fast. If thread creation is very slow on your system you |
874 | might want to use larger values. |
1531 | might want to use larger values. |
875 | |
1532 | |
|
|
1533 | IO::AIO::idle_timeout $seconds |
|
|
1534 | Sets the minimum idle timeout (default 10) after which worker |
|
|
1535 | threads are allowed to exit. SEe "IO::AIO::max_idle". |
|
|
1536 | |
876 | $oldmaxreqs = IO::AIO::max_outstanding $maxreqs |
1537 | IO::AIO::max_outstanding $maxreqs |
|
|
1538 | Sets the maximum number of outstanding requests to $nreqs. If you do |
|
|
1539 | queue up more than this number of requests, the next call to |
|
|
1540 | "IO::AIO::poll_cb" (and other functions calling "poll_cb", such as |
|
|
1541 | "IO::AIO::flush" or "IO::AIO::poll") will block until the limit is |
|
|
1542 | no longer exceeded. |
|
|
1543 | |
|
|
1544 | In other words, this setting does not enforce a queue limit, but can |
|
|
1545 | be used to make poll functions block if the limit is exceeded. |
|
|
1546 | |
877 | This is a very bad function to use in interactive programs because |
1547 | This is a very bad function to use in interactive programs because |
878 | it blocks, and a bad way to reduce concurrency because it is |
1548 | it blocks, and a bad way to reduce concurrency because it is |
879 | inexact: Better use an "aio_group" together with a feed callback. |
1549 | inexact: Better use an "aio_group" together with a feed callback. |
880 | |
1550 | |
881 | Sets the maximum number of outstanding requests to $nreqs. If you do |
1551 | Its main use is in scripts without an event loop - when you want to |
882 | queue up more than this number of requests, the next call to the |
1552 | stat a lot of files, you can write somehting like this: |
883 | "poll_cb" (and "poll_some" and other functions calling "poll_cb") |
|
|
884 | function will block until the limit is no longer exceeded. |
|
|
885 | |
1553 | |
886 | The default value is very large, so there is no practical limit on |
1554 | IO::AIO::max_outstanding 32; |
|
|
1555 | |
|
|
1556 | for my $path (...) { |
|
|
1557 | aio_stat $path , ...; |
|
|
1558 | IO::AIO::poll_cb; |
|
|
1559 | } |
|
|
1560 | |
|
|
1561 | IO::AIO::flush; |
|
|
1562 | |
|
|
1563 | The call to "poll_cb" inside the loop will normally return |
|
|
1564 | instantly, but as soon as more thna 32 reqeusts are in-flight, it |
|
|
1565 | will block until some requests have been handled. This keeps the |
|
|
1566 | loop from pushing a large number of "aio_stat" requests onto the |
|
|
1567 | queue. |
|
|
1568 | |
|
|
1569 | The default value for "max_outstanding" is very large, so there is |
887 | the number of outstanding requests. |
1570 | no practical limit on the number of outstanding requests. |
888 | |
|
|
889 | You can still queue as many requests as you want. Therefore, |
|
|
890 | "max_oustsanding" is mainly useful in simple scripts (with low |
|
|
891 | values) or as a stop gap to shield against fatal memory overflow |
|
|
892 | (with large values). |
|
|
893 | |
1571 | |
894 | STATISTICAL INFORMATION |
1572 | STATISTICAL INFORMATION |
895 | IO::AIO::nreqs |
1573 | IO::AIO::nreqs |
896 | Returns the number of requests currently in the ready, execute or |
1574 | Returns the number of requests currently in the ready, execute or |
897 | pending states (i.e. for which their callback has not been invoked |
1575 | pending states (i.e. for which their callback has not been invoked |
… | |
… | |
908 | |
1586 | |
909 | IO::AIO::npending |
1587 | IO::AIO::npending |
910 | Returns the number of requests currently in the pending state |
1588 | Returns the number of requests currently in the pending state |
911 | (executed, but not yet processed by poll_cb). |
1589 | (executed, but not yet processed by poll_cb). |
912 | |
1590 | |
|
|
1591 | MISCELLANEOUS FUNCTIONS |
|
|
1592 | IO::AIO implements some functions that are useful when you want to use |
|
|
1593 | some "Advanced I/O" function not available to in Perl, without going the |
|
|
1594 | "Asynchronous I/O" route. Many of these have an asynchronous "aio_*" |
|
|
1595 | counterpart. |
|
|
1596 | |
|
|
1597 | IO::AIO::sendfile $ofh, $ifh, $offset, $count |
|
|
1598 | Calls the "eio_sendfile_sync" function, which is like |
|
|
1599 | "aio_sendfile", but is blocking (this makes most sense if you know |
|
|
1600 | the input data is likely cached already and the output filehandle is |
|
|
1601 | set to non-blocking operations). |
|
|
1602 | |
|
|
1603 | Returns the number of bytes copied, or -1 on error. |
|
|
1604 | |
|
|
1605 | IO::AIO::fadvise $fh, $offset, $len, $advice |
|
|
1606 | Simply calls the "posix_fadvise" function (see its manpage for |
|
|
1607 | details). The following advice constants are available: |
|
|
1608 | "IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL", |
|
|
1609 | "IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE", |
|
|
1610 | "IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED". |
|
|
1611 | |
|
|
1612 | On systems that do not implement "posix_fadvise", this function |
|
|
1613 | returns ENOSYS, otherwise the return value of "posix_fadvise". |
|
|
1614 | |
|
|
1615 | IO::AIO::madvise $scalar, $offset, $len, $advice |
|
|
1616 | Simply calls the "posix_madvise" function (see its manpage for |
|
|
1617 | details). The following advice constants are available: |
|
|
1618 | "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL", |
|
|
1619 | "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED", |
|
|
1620 | "IO::AIO::MADV_DONTNEED". |
|
|
1621 | |
|
|
1622 | On systems that do not implement "posix_madvise", this function |
|
|
1623 | returns ENOSYS, otherwise the return value of "posix_madvise". |
|
|
1624 | |
|
|
1625 | IO::AIO::mprotect $scalar, $offset, $len, $protect |
|
|
1626 | Simply calls the "mprotect" function on the preferably AIO::mmap'ed |
|
|
1627 | $scalar (see its manpage for details). The following protect |
|
|
1628 | constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ", |
|
|
1629 | "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC". |
|
|
1630 | |
|
|
1631 | On systems that do not implement "mprotect", this function returns |
|
|
1632 | ENOSYS, otherwise the return value of "mprotect". |
|
|
1633 | |
|
|
1634 | IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] |
|
|
1635 | Memory-maps a file (or anonymous memory range) and attaches it to |
|
|
1636 | the given $scalar, which will act like a string scalar. Returns true |
|
|
1637 | on success, and false otherwise. |
|
|
1638 | |
|
|
1639 | The only operations allowed on the scalar are "substr"/"vec" that |
|
|
1640 | don't change the string length, and most read-only operations such |
|
|
1641 | as copying it or searching it with regexes and so on. |
|
|
1642 | |
|
|
1643 | Anything else is unsafe and will, at best, result in memory leaks. |
|
|
1644 | |
|
|
1645 | The memory map associated with the $scalar is automatically removed |
|
|
1646 | when the $scalar is destroyed, or when the "IO::AIO::mmap" or |
|
|
1647 | "IO::AIO::munmap" functions are called. |
|
|
1648 | |
|
|
1649 | This calls the "mmap"(2) function internally. See your system's |
|
|
1650 | manual page for details on the $length, $prot and $flags parameters. |
|
|
1651 | |
|
|
1652 | The $length must be larger than zero and smaller than the actual |
|
|
1653 | filesize. |
|
|
1654 | |
|
|
1655 | $prot is a combination of "IO::AIO::PROT_NONE", |
|
|
1656 | "IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or |
|
|
1657 | "IO::AIO::PROT_WRITE", |
|
|
1658 | |
|
|
1659 | $flags can be a combination of "IO::AIO::MAP_SHARED" or |
|
|
1660 | "IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when |
|
|
1661 | not available, the are 0): "IO::AIO::MAP_ANONYMOUS" (which is set to |
|
|
1662 | "MAP_ANON" if your system only provides this constant), |
|
|
1663 | "IO::AIO::MAP_LOCKED", "IO::AIO::MAP_NORESERVE", |
|
|
1664 | "IO::AIO::MAP_POPULATE", "IO::AIO::MAP_NONBLOCK", |
|
|
1665 | "IO::AIO::MAP_FIXED", "IO::AIO::MAP_GROWSDOWN", |
|
|
1666 | "IO::AIO::MAP_32BIT", "IO::AIO::MAP_HUGETLB" or |
|
|
1667 | "IO::AIO::MAP_STACK". |
|
|
1668 | |
|
|
1669 | If $fh is "undef", then a file descriptor of -1 is passed. |
|
|
1670 | |
|
|
1671 | $offset is the offset from the start of the file - it generally must |
|
|
1672 | be a multiple of "IO::AIO::PAGESIZE" and defaults to 0. |
|
|
1673 | |
|
|
1674 | Example: |
|
|
1675 | |
|
|
1676 | use Digest::MD5; |
|
|
1677 | use IO::AIO; |
|
|
1678 | |
|
|
1679 | open my $fh, "<verybigfile" |
|
|
1680 | or die "$!"; |
|
|
1681 | |
|
|
1682 | IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh |
|
|
1683 | or die "verybigfile: $!"; |
|
|
1684 | |
|
|
1685 | my $fast_md5 = md5 $data; |
|
|
1686 | |
|
|
1687 | IO::AIO::munmap $scalar |
|
|
1688 | Removes a previous mmap and undefines the $scalar. |
|
|
1689 | |
|
|
1690 | IO::AIO::munlock $scalar, $offset = 0, $length = undef |
|
|
1691 | Calls the "munlock" function, undoing the effects of a previous |
|
|
1692 | "aio_mlock" call (see its description for details). |
|
|
1693 | |
|
|
1694 | IO::AIO::munlockall |
|
|
1695 | Calls the "munlockall" function. |
|
|
1696 | |
|
|
1697 | On systems that do not implement "munlockall", this function returns |
|
|
1698 | ENOSYS, otherwise the return value of "munlockall". |
|
|
1699 | |
|
|
1700 | IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags |
|
|
1701 | Calls the GNU/Linux splice(2) syscall, if available. If $r_off or |
|
|
1702 | $w_off are "undef", then "NULL" is passed for these, otherwise they |
|
|
1703 | should be the file offset. |
|
|
1704 | |
|
|
1705 | $r_fh and $w_fh should not refer to the same file, as splice might |
|
|
1706 | silently corrupt the data in this case. |
|
|
1707 | |
|
|
1708 | The following symbol flag values are available: |
|
|
1709 | "IO::AIO::SPLICE_F_MOVE", "IO::AIO::SPLICE_F_NONBLOCK", |
|
|
1710 | "IO::AIO::SPLICE_F_MORE" and "IO::AIO::SPLICE_F_GIFT". |
|
|
1711 | |
|
|
1712 | See the splice(2) manpage for details. |
|
|
1713 | |
|
|
1714 | IO::AIO::tee $r_fh, $w_fh, $length, $flags |
|
|
1715 | Calls the GNU/Linux tee(2) syscall, see its manpage and the |
|
|
1716 | description for "IO::AIO::splice" above for details. |
|
|
1717 | |
|
|
1718 | $actual_size = IO::AIO::pipesize $r_fh[, $new_size] |
|
|
1719 | Attempts to query or change the pipe buffer size. Obviously works |
|
|
1720 | only on pipes, and currently works only on GNU/Linux systems, and |
|
|
1721 | fails with -1/"ENOSYS" everywhere else. If anybody knows how to |
|
|
1722 | influence pipe buffer size on other systems, drop me a note. |
|
|
1723 | |
|
|
1724 | ($rfh, $wfh) = IO::AIO::pipe2 [$flags] |
|
|
1725 | This is a direct interface to the Linux pipe2(2) system call. If |
|
|
1726 | $flags is missing or 0, then this should be the same as a call to |
|
|
1727 | perl's built-in "pipe" function and create a new pipe, and works on |
|
|
1728 | systems that lack the pipe2 syscall. On win32, this case invokes |
|
|
1729 | "_pipe (..., 4096, O_BINARY)". |
|
|
1730 | |
|
|
1731 | If $flags is non-zero, it tries to invoke the pipe2 system call with |
|
|
1732 | the given flags (Linux 2.6.27, glibc 2.9). |
|
|
1733 | |
|
|
1734 | On success, the read and write file handles are returned. |
|
|
1735 | |
|
|
1736 | On error, nothing will be returned. If the pipe2 syscall is missing |
|
|
1737 | and $flags is non-zero, fails with "ENOSYS". |
|
|
1738 | |
|
|
1739 | Please refer to pipe2(2) for more info on the $flags, but at the |
|
|
1740 | time of this writing, "IO::AIO::O_CLOEXEC", "IO::AIO::O_NONBLOCK" |
|
|
1741 | and "IO::AIO::O_DIRECT" (Linux 3.4, for packet-based pipes) were |
|
|
1742 | supported. |
|
|
1743 | |
|
|
1744 | EVENT LOOP INTEGRATION |
|
|
1745 | It is recommended to use AnyEvent::AIO to integrate IO::AIO |
|
|
1746 | automatically into many event loops: |
|
|
1747 | |
|
|
1748 | # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) |
|
|
1749 | use AnyEvent::AIO; |
|
|
1750 | |
|
|
1751 | You can also integrate IO::AIO manually into many event loops, here are |
|
|
1752 | some examples of how to do this: |
|
|
1753 | |
|
|
1754 | # EV integration |
|
|
1755 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
|
|
1756 | |
|
|
1757 | # Event integration |
|
|
1758 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
1759 | poll => 'r', |
|
|
1760 | cb => \&IO::AIO::poll_cb); |
|
|
1761 | |
|
|
1762 | # Glib/Gtk2 integration |
|
|
1763 | add_watch Glib::IO IO::AIO::poll_fileno, |
|
|
1764 | in => sub { IO::AIO::poll_cb; 1 }; |
|
|
1765 | |
|
|
1766 | # Tk integration |
|
|
1767 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
|
|
1768 | readable => \&IO::AIO::poll_cb); |
|
|
1769 | |
|
|
1770 | # Danga::Socket integration |
|
|
1771 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
|
|
1772 | \&IO::AIO::poll_cb); |
|
|
1773 | |
913 | FORK BEHAVIOUR |
1774 | FORK BEHAVIOUR |
914 | This module should do "the right thing" when the process using it forks: |
1775 | Usage of pthreads in a program changes the semantics of fork |
|
|
1776 | considerably. Specifically, only async-safe functions can be called |
|
|
1777 | after fork. Perl doesn't know about this, so in general, you cannot call |
|
|
1778 | fork with defined behaviour in perl if pthreads are involved. IO::AIO |
|
|
1779 | uses pthreads, so this applies, but many other extensions and (for |
|
|
1780 | inexplicable reasons) perl itself often is linked against pthreads, so |
|
|
1781 | this limitation applies to quite a lot of perls. |
915 | |
1782 | |
916 | Before the fork, IO::AIO enters a quiescent state where no requests can |
1783 | This module no longer tries to fight your OS, or POSIX. That means |
917 | be added in other threads and no results will be processed. After the |
1784 | IO::AIO only works in the process that loaded it. Forking is fully |
918 | fork the parent simply leaves the quiescent state and continues |
1785 | supported, but using IO::AIO in the child is not. |
919 | request/result processing, while the child frees the request/result |
|
|
920 | queue (so that the requests started before the fork will only be handled |
|
|
921 | in the parent). Threads will be started on demand until the limit set in |
|
|
922 | the parent process has been reached again. |
|
|
923 | |
1786 | |
924 | In short: the parent will, after a short pause, continue as if fork had |
1787 | You might get around by not *using* IO::AIO before (or after) forking. |
925 | not been called, while the child will act as if IO::AIO has not been |
1788 | You could also try to call the IO::AIO::reinit function in the child: |
926 | used yet. |
1789 | |
|
|
1790 | IO::AIO::reinit |
|
|
1791 | Abandons all current requests and I/O threads and simply |
|
|
1792 | reinitialises all data structures. This is not an operation |
|
|
1793 | supported by any standards, but happens to work on GNU/Linux and |
|
|
1794 | some newer BSD systems. |
|
|
1795 | |
|
|
1796 | The only reasonable use for this function is to call it after |
|
|
1797 | forking, if "IO::AIO" was used in the parent. Calling it while |
|
|
1798 | IO::AIO is active in the process will result in undefined behaviour. |
|
|
1799 | Calling it at any time will also result in any undefined (by POSIX) |
|
|
1800 | behaviour. |
927 | |
1801 | |
928 | MEMORY USAGE |
1802 | MEMORY USAGE |
929 | Per-request usage: |
1803 | Per-request usage: |
930 | |
1804 | |
931 | Each aio request uses - depending on your architecture - around 100-200 |
1805 | Each aio request uses - depending on your architecture - around 100-200 |
… | |
… | |
945 | |
1819 | |
946 | KNOWN BUGS |
1820 | KNOWN BUGS |
947 | Known bugs will be fixed in the next release. |
1821 | Known bugs will be fixed in the next release. |
948 | |
1822 | |
949 | SEE ALSO |
1823 | SEE ALSO |
950 | Coro::AIO. |
1824 | AnyEvent::AIO for easy integration into event loops, Coro::AIO for a |
|
|
1825 | more natural syntax. |
951 | |
1826 | |
952 | AUTHOR |
1827 | AUTHOR |
953 | Marc Lehmann <schmorp@schmorp.de> |
1828 | Marc Lehmann <schmorp@schmorp.de> |
954 | http://home.schmorp.de/ |
1829 | http://home.schmorp.de/ |
955 | |
1830 | |