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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 (EV, Event, Glib, Tk, POE, urxvt, pureperl...) |
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30 | use AnyEvent::AIO; |
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31 | |
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32 | # EV integration |
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33 | my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
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34 | |
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35 | # Event integration |
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36 | Event->io (fd => IO::AIO::poll_fileno, |
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37 | poll => 'r', |
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38 | cb => \&IO::AIO::poll_cb); |
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39 | |
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40 | # Glib/Gtk2 integration |
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41 | add_watch Glib::IO IO::AIO::poll_fileno, |
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42 | in => sub { IO::AIO::poll_cb; 1 }; |
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43 | |
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44 | # Tk integration |
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45 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
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46 | readable => \&IO::AIO::poll_cb); |
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47 | |
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48 | # Danga::Socket integration |
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49 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
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50 | \&IO::AIO::poll_cb); |
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51 | |
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52 | DESCRIPTION |
29 | DESCRIPTION |
53 | This module implements asynchronous I/O using whatever means your |
30 | This module implements asynchronous I/O using whatever means your |
54 | operating system supports. |
31 | operating system supports. It is implemented as an interface to "libeio" |
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32 | (<http://software.schmorp.de/pkg/libeio.html>). |
55 | |
33 | |
56 | Asynchronous means that operations that can normally block your program |
34 | Asynchronous means that operations that can normally block your program |
57 | (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 |
58 | 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 |
59 | 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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64 | operations concurrently. |
42 | operations concurrently. |
65 | |
43 | |
66 | 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 |
67 | sockets), using these functions on file descriptors that support |
45 | sockets), using these functions on file descriptors that support |
68 | nonblocking operation (again, sockets, pipes etc.) is very inefficient. |
46 | nonblocking operation (again, sockets, pipes etc.) is very inefficient. |
69 | 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 |
70 | naturally fit into such an event loop itself. |
48 | naturally fit into such an event loop itself. |
71 | |
49 | |
72 | 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 |
73 | 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 |
74 | 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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83 | 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 |
84 | 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 |
85 | call "poll_cb" (or other "aio_" functions) recursively. |
63 | call "poll_cb" (or other "aio_" functions) recursively. |
86 | |
64 | |
87 | EXAMPLE |
65 | EXAMPLE |
88 | 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 |
89 | /etc/passwd asynchronously: |
67 | asynchronously: |
90 | |
68 | |
91 | use Fcntl; |
69 | use Fcntl; |
92 | use Event; |
70 | use EV; |
93 | use IO::AIO; |
71 | use IO::AIO; |
94 | |
72 | |
95 | # register the IO::AIO callback with Event |
73 | # register the IO::AIO callback with EV |
96 | Event->io (fd => IO::AIO::poll_fileno, |
74 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
97 | poll => 'r', |
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98 | cb => \&IO::AIO::poll_cb); |
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99 | |
75 | |
100 | # queue the request to open /etc/passwd |
76 | # queue the request to open /etc/passwd |
101 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
77 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
102 | my $fh = shift |
78 | my $fh = shift |
103 | or die "error while opening: $!"; |
79 | or die "error while opening: $!"; |
104 | |
80 | |
105 | # stat'ing filehandles is generally non-blocking |
81 | # stat'ing filehandles is generally non-blocking |
106 | my $size = -s $fh; |
82 | my $size = -s $fh; |
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115 | |
91 | |
116 | # file contents now in $contents |
92 | # file contents now in $contents |
117 | print $contents; |
93 | print $contents; |
118 | |
94 | |
119 | # exit event loop and program |
95 | # exit event loop and program |
120 | Event::unloop; |
96 | EV::unloop; |
121 | }; |
97 | }; |
122 | }; |
98 | }; |
123 | |
99 | |
124 | # possibly queue up other requests, or open GUI windows, |
100 | # possibly queue up other requests, or open GUI windows, |
125 | # check for sockets etc. etc. |
101 | # check for sockets etc. etc. |
126 | |
102 | |
127 | # process events as long as there are some: |
103 | # process events as long as there are some: |
128 | Event::loop; |
104 | EV::loop; |
129 | |
105 | |
130 | REQUEST ANATOMY AND LIFETIME |
106 | REQUEST ANATOMY AND LIFETIME |
131 | Every "aio_*" function creates a request. which is a C data structure |
107 | Every "aio_*" function creates a request. which is a C data structure |
132 | not directly visible to Perl. |
108 | not directly visible to Perl. |
133 | |
109 | |
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169 | anymore (except possibly for the Perl object, but its connection to |
145 | anymore (except possibly for the Perl object, but its connection to |
170 | the actual aio request is severed and calling its methods will |
146 | the actual aio request is severed and calling its methods will |
171 | either do nothing or result in a runtime error). |
147 | either do nothing or result in a runtime error). |
172 | |
148 | |
173 | FUNCTIONS |
149 | FUNCTIONS |
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150 | QUICK OVERVIEW |
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151 | This section simply lists the prototypes of the most important functions |
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152 | for quick reference. See the following sections for function-by-function |
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153 | documentation. |
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154 | |
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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_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
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158 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
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159 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
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160 | aio_readahead $fh,$offset,$length, $callback->($retval) |
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161 | aio_stat $fh_or_path, $callback->($status) |
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162 | aio_lstat $fh, $callback->($status) |
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163 | aio_statvfs $fh_or_path, $callback->($statvfs) |
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164 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
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165 | aio_chown $fh_or_path, $uid, $gid, $callback->($status) |
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166 | aio_truncate $fh_or_path, $offset, $callback->($status) |
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167 | aio_chmod $fh_or_path, $mode, $callback->($status) |
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168 | aio_unlink $pathname, $callback->($status) |
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169 | aio_mknod $path, $mode, $dev, $callback->($status) |
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170 | aio_link $srcpath, $dstpath, $callback->($status) |
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171 | aio_symlink $srcpath, $dstpath, $callback->($status) |
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172 | aio_readlink $path, $callback->($link) |
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173 | aio_realpath $path, $callback->($link) |
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174 | aio_rename $srcpath, $dstpath, $callback->($status) |
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175 | aio_mkdir $pathname, $mode, $callback->($status) |
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176 | aio_rmdir $pathname, $callback->($status) |
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177 | aio_readdir $pathname, $callback->($entries) |
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178 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
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179 | IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST |
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180 | IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN |
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181 | aio_load $path, $data, $callback->($status) |
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182 | aio_copy $srcpath, $dstpath, $callback->($status) |
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183 | aio_move $srcpath, $dstpath, $callback->($status) |
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184 | aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
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185 | aio_rmtree $path, $callback->($status) |
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186 | aio_sync $callback->($status) |
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187 | aio_fsync $fh, $callback->($status) |
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188 | aio_fdatasync $fh, $callback->($status) |
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189 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
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190 | aio_pathsync $path, $callback->($status) |
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191 | aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
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192 | aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
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193 | aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
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194 | aio_mlockall $flags, $callback->($status) |
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195 | aio_group $callback->(...) |
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196 | aio_nop $callback->() |
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197 | |
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198 | $prev_pri = aioreq_pri [$pri] |
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199 | aioreq_nice $pri_adjust |
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200 | |
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201 | IO::AIO::poll_wait |
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202 | IO::AIO::poll_cb |
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203 | IO::AIO::poll |
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204 | IO::AIO::flush |
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205 | IO::AIO::max_poll_reqs $nreqs |
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206 | IO::AIO::max_poll_time $seconds |
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207 | IO::AIO::min_parallel $nthreads |
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208 | IO::AIO::max_parallel $nthreads |
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209 | IO::AIO::max_idle $nthreads |
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210 | IO::AIO::idle_timeout $seconds |
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211 | IO::AIO::max_outstanding $maxreqs |
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212 | IO::AIO::nreqs |
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213 | IO::AIO::nready |
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214 | IO::AIO::npending |
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215 | |
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216 | IO::AIO::sendfile $ofh, $ifh, $offset, $count |
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217 | IO::AIO::fadvise $fh, $offset, $len, $advice |
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218 | IO::AIO::madvise $scalar, $offset, $length, $advice |
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219 | IO::AIO::mprotect $scalar, $offset, $length, $protect |
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220 | IO::AIO::munlock $scalar, $offset = 0, $length = undef |
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221 | IO::AIO::munlockall |
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222 | |
174 | AIO REQUEST FUNCTIONS |
223 | AIO REQUEST FUNCTIONS |
175 | All the "aio_*" calls are more or less thin wrappers around the syscall |
224 | All the "aio_*" calls are more or less thin wrappers around the syscall |
176 | with the same name (sans "aio_"). The arguments are similar or |
225 | with the same name (sans "aio_"). The arguments are similar or |
177 | identical, and they all accept an additional (and optional) $callback |
226 | identical, and they all accept an additional (and optional) $callback |
178 | argument which must be a code reference. This code reference will get |
227 | argument which must be a code reference. This code reference will get |
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249 | will be modified by the umask in effect then the request is being |
298 | will be modified by the umask in effect then the request is being |
250 | executed, so better never change the umask. |
299 | executed, so better never change the umask. |
251 | |
300 | |
252 | Example: |
301 | Example: |
253 | |
302 | |
254 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
303 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
255 | if ($_[0]) { |
304 | if ($_[0]) { |
256 | print "open successful, fh is $_[0]\n"; |
305 | print "open successful, fh is $_[0]\n"; |
257 | ... |
306 | ... |
258 | } else { |
307 | } else { |
259 | die "open failed: $!\n"; |
308 | die "open failed: $!\n"; |
260 | } |
309 | } |
261 | }; |
310 | }; |
262 | |
311 | |
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312 | In addition to all the common open modes/flags ("O_RDONLY", |
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313 | "O_WRONLY", "O_RDWR", "O_CREAT", "O_TRUNC", "O_EXCL" and |
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314 | "O_APPEND"), the following POSIX and non-POSIX constants are |
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315 | available (missing ones on your system are, as usual, 0): |
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316 | |
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317 | "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY", |
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318 | "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY", |
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319 | "O_DSYNC", "O_RSYNC", "O_SYNC" and "O_TTY_INIT". |
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320 | |
263 | aio_close $fh, $callback->($status) |
321 | aio_close $fh, $callback->($status) |
264 | Asynchronously close a file and call the callback with the result |
322 | Asynchronously close a file and call the callback with the result |
265 | code. |
323 | code. |
266 | |
324 | |
267 | Unfortunately, you can't do this to perl. Perl *insists* very |
325 | Unfortunately, you can't do this to perl. Perl *insists* very |
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310 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
368 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
311 | Tries to copy $length bytes from $in_fh to $out_fh. It starts |
369 | Tries to copy $length bytes from $in_fh to $out_fh. It starts |
312 | reading at byte offset $in_offset, and starts writing at the current |
370 | reading at byte offset $in_offset, and starts writing at the current |
313 | file offset of $out_fh. Because of that, it is not safe to issue |
371 | file offset of $out_fh. Because of that, it is not safe to issue |
314 | more than one "aio_sendfile" per $out_fh, as they will interfere |
372 | more than one "aio_sendfile" per $out_fh, as they will interfere |
315 | with each other. |
373 | with each other. The same $in_fh works fine though, as this function |
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374 | does not move or use the file offset of $in_fh. |
316 | |
375 | |
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376 | Please note that "aio_sendfile" can read more bytes from $in_fh than |
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377 | are written, and there is no way to find out how many more bytes |
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378 | have been read from "aio_sendfile" alone, as "aio_sendfile" only |
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379 | provides the number of bytes written to $out_fh. Only if the result |
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380 | value equals $length one can assume that $length bytes have been |
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381 | read. |
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382 | |
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383 | Unlike with other "aio_" functions, it makes a lot of sense to use |
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384 | "aio_sendfile" on non-blocking sockets, as long as one end |
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385 | (typically the $in_fh) is a file - the file I/O will then be |
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386 | asynchronous, while the socket I/O will be non-blocking. Note, |
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387 | however, that you can run into a trap where "aio_sendfile" reads |
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388 | some data with readahead, then fails to write all data, and when the |
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389 | socket is ready the next time, the data in the cache is already |
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390 | lost, forcing "aio_sendfile" to again hit the disk. Explicit |
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391 | "aio_read" + "aio_write" let's you better control resource usage. |
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392 | |
317 | This call tries to make use of a native "sendfile" syscall to |
393 | This call tries to make use of a native "sendfile"-like syscall to |
318 | provide zero-copy operation. For this to work, $out_fh should refer |
394 | provide zero-copy operation. For this to work, $out_fh should refer |
319 | to a socket, and $in_fh should refer to mmap'able file. |
395 | to a socket, and $in_fh should refer to an mmap'able file. |
320 | |
396 | |
321 | If the native sendfile call fails or is not implemented, it will be |
397 | If a native sendfile cannot be found or it fails with "ENOSYS", |
322 | emulated, so you can call "aio_sendfile" on any type of filehandle |
398 | "EINVAL", "ENOTSUP", "EOPNOTSUPP", "EAFNOSUPPORT", "EPROTOTYPE" or |
323 | regardless of the limitations of the operating system. |
399 | "ENOTSOCK", it will be emulated, so you can call "aio_sendfile" on |
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400 | any type of filehandle regardless of the limitations of the |
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401 | operating system. |
324 | |
402 | |
325 | Please note, however, that "aio_sendfile" can read more bytes from |
403 | As native sendfile syscalls (as practically any non-POSIX interface |
326 | $in_fh than are written, and there is no way to find out how many |
404 | hacked together in a hurry to improve benchmark numbers) tend to be |
327 | bytes have been read from "aio_sendfile" alone, as "aio_sendfile" |
405 | rather buggy on many systems, this implementation tries to work |
328 | only provides the number of bytes written to $out_fh. Only if the |
406 | around some known bugs in Linux and FreeBSD kernels (probably |
329 | result value equals $length one can assume that $length bytes have |
407 | others, too), but that might fail, so you really really should check |
330 | been read. |
408 | the return value of "aio_sendfile" - fewre bytes than expected might |
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409 | have been transferred. |
331 | |
410 | |
332 | aio_readahead $fh,$offset,$length, $callback->($retval) |
411 | aio_readahead $fh,$offset,$length, $callback->($retval) |
333 | "aio_readahead" populates the page cache with data from a file so |
412 | "aio_readahead" populates the page cache with data from a file so |
334 | that subsequent reads from that file will not block on disk I/O. The |
413 | that subsequent reads from that file will not block on disk I/O. The |
335 | $offset argument specifies the starting point from which data is to |
414 | $offset argument specifies the starting point from which data is to |
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356 | Currently, the stats are always 64-bit-stats, i.e. instead of |
435 | Currently, the stats are always 64-bit-stats, i.e. instead of |
357 | returning an error when stat'ing a large file, the results will be |
436 | returning an error when stat'ing a large file, the results will be |
358 | silently truncated unless perl itself is compiled with large file |
437 | silently truncated unless perl itself is compiled with large file |
359 | support. |
438 | support. |
360 | |
439 | |
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440 | To help interpret the mode and dev/rdev stat values, IO::AIO offers |
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441 | the following constants and functions (if not implemented, the |
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442 | constants will be 0 and the functions will either "croak" or fall |
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443 | back on traditional behaviour). |
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444 | |
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445 | "S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG", |
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446 | "S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t", |
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447 | "IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor". |
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448 | |
361 | Example: Print the length of /etc/passwd: |
449 | Example: Print the length of /etc/passwd: |
362 | |
450 | |
363 | aio_stat "/etc/passwd", sub { |
451 | aio_stat "/etc/passwd", sub { |
364 | $_[0] and die "stat failed: $!"; |
452 | $_[0] and die "stat failed: $!"; |
365 | print "size is ", -s _, "\n"; |
453 | print "size is ", -s _, "\n"; |
366 | }; |
454 | }; |
367 | |
455 | |
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456 | aio_statvfs $fh_or_path, $callback->($statvfs) |
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457 | Works like the POSIX "statvfs" or "fstatvfs" syscalls, depending on |
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458 | whether a file handle or path was passed. |
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459 | |
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460 | On success, the callback is passed a hash reference with the |
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461 | following members: "bsize", "frsize", "blocks", "bfree", "bavail", |
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462 | "files", "ffree", "favail", "fsid", "flag" and "namemax". On |
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463 | failure, "undef" is passed. |
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464 | |
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465 | The following POSIX IO::AIO::ST_* constants are defined: "ST_RDONLY" |
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466 | and "ST_NOSUID". |
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467 | |
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468 | The following non-POSIX IO::AIO::ST_* flag masks are defined to |
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469 | their correct value when available, or to 0 on systems that do not |
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470 | support them: "ST_NODEV", "ST_NOEXEC", "ST_SYNCHRONOUS", |
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471 | "ST_MANDLOCK", "ST_WRITE", "ST_APPEND", "ST_IMMUTABLE", |
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472 | "ST_NOATIME", "ST_NODIRATIME" and "ST_RELATIME". |
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473 | |
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474 | Example: stat "/wd" and dump out the data if successful. |
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475 | |
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476 | aio_statvfs "/wd", sub { |
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477 | my $f = $_[0] |
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478 | or die "statvfs: $!"; |
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479 | |
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480 | use Data::Dumper; |
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481 | say Dumper $f; |
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482 | }; |
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483 | |
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484 | # result: |
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485 | { |
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486 | bsize => 1024, |
|
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487 | bfree => 4333064312, |
|
|
488 | blocks => 10253828096, |
|
|
489 | files => 2050765568, |
|
|
490 | flag => 4096, |
|
|
491 | favail => 2042092649, |
|
|
492 | bavail => 4333064312, |
|
|
493 | ffree => 2042092649, |
|
|
494 | namemax => 255, |
|
|
495 | frsize => 1024, |
|
|
496 | fsid => 1810 |
|
|
497 | } |
|
|
498 | |
368 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
499 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
369 | Works like perl's "utime" function (including the special case of |
500 | Works like perl's "utime" function (including the special case of |
370 | $atime and $mtime being undef). Fractional times are supported if |
501 | $atime and $mtime being undef). Fractional times are supported if |
371 | the underlying syscalls support them. |
502 | the underlying syscalls support them. |
372 | |
503 | |
… | |
… | |
410 | |
541 | |
411 | The only (POSIX-) portable way of calling this function is: |
542 | The only (POSIX-) portable way of calling this function is: |
412 | |
543 | |
413 | aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
544 | aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
414 | |
545 | |
|
|
546 | See "aio_stat" for info about some potentially helpful extra |
|
|
547 | constants and functions. |
|
|
548 | |
415 | aio_link $srcpath, $dstpath, $callback->($status) |
549 | aio_link $srcpath, $dstpath, $callback->($status) |
416 | Asynchronously create a new link to the existing object at $srcpath |
550 | Asynchronously create a new link to the existing object at $srcpath |
417 | at the path $dstpath and call the callback with the result code. |
551 | at the path $dstpath and call the callback with the result code. |
418 | |
552 | |
419 | aio_symlink $srcpath, $dstpath, $callback->($status) |
553 | aio_symlink $srcpath, $dstpath, $callback->($status) |
… | |
… | |
424 | aio_readlink $path, $callback->($link) |
558 | aio_readlink $path, $callback->($link) |
425 | Asynchronously read the symlink specified by $path and pass it to |
559 | Asynchronously read the symlink specified by $path and pass it to |
426 | the callback. If an error occurs, nothing or undef gets passed to |
560 | the callback. If an error occurs, nothing or undef gets passed to |
427 | the callback. |
561 | the callback. |
428 | |
562 | |
|
|
563 | aio_realpath $path, $callback->($path) |
|
|
564 | Asynchronously make the path absolute and resolve any symlinks in |
|
|
565 | $path. The resulting path only consists of directories (Same as |
|
|
566 | Cwd::realpath). |
|
|
567 | |
|
|
568 | This request can be used to get the absolute path of the current |
|
|
569 | working directory by passing it a path of . (a single dot). |
|
|
570 | |
429 | aio_rename $srcpath, $dstpath, $callback->($status) |
571 | aio_rename $srcpath, $dstpath, $callback->($status) |
430 | Asynchronously rename the object at $srcpath to $dstpath, just as |
572 | Asynchronously rename the object at $srcpath to $dstpath, just as |
431 | rename(2) and call the callback with the result code. |
573 | rename(2) and call the callback with the result code. |
432 | |
574 | |
433 | aio_mkdir $pathname, $mode, $callback->($status) |
575 | aio_mkdir $pathname, $mode, $callback->($status) |
… | |
… | |
455 | The flags are a combination of the following constants, ORed |
597 | The flags are a combination of the following constants, ORed |
456 | together (the flags will also be passed to the callback, possibly |
598 | together (the flags will also be passed to the callback, possibly |
457 | modified): |
599 | modified): |
458 | |
600 | |
459 | IO::AIO::READDIR_DENTS |
601 | IO::AIO::READDIR_DENTS |
460 | When this flag is off, then the callback gets an arrayref with |
602 | When this flag is off, then the callback gets an arrayref |
461 | of names only (as with "aio_readdir"), otherwise it gets an |
603 | consisting of names only (as with "aio_readdir"), otherwise it |
462 | arrayref with "[$name, $type, $inode]" arrayrefs, each |
604 | gets an arrayref with "[$name, $type, $inode]" arrayrefs, each |
463 | describing a single directory entry in more detail. |
605 | describing a single directory entry in more detail. |
464 | |
606 | |
465 | $name is the name of the entry. |
607 | $name is the name of the entry. |
466 | |
608 | |
467 | $type is one of the "IO::AIO::DT_xxx" constants: |
609 | $type is one of the "IO::AIO::DT_xxx" constants: |
… | |
… | |
474 | you need to know, you have to run stat yourself. Also, for speed |
616 | you need to know, you have to run stat yourself. Also, for speed |
475 | reasons, the $type scalars are read-only: you can not modify |
617 | reasons, the $type scalars are read-only: you can not modify |
476 | them. |
618 | them. |
477 | |
619 | |
478 | $inode is the inode number (which might not be exact on systems |
620 | $inode is the inode number (which might not be exact on systems |
479 | with 64 bit inode numbers and 32 bit perls). On systems that do |
621 | with 64 bit inode numbers and 32 bit perls). This field has |
480 | not deliver the inode information, this will always be zero. |
622 | unspecified content on systems that do not deliver the inode |
|
|
623 | information. |
481 | |
624 | |
482 | IO::AIO::READDIR_DIRS_FIRST |
625 | IO::AIO::READDIR_DIRS_FIRST |
483 | When this flag is set, then the names will be returned in an |
626 | When this flag is set, then the names will be returned in an |
484 | order where likely directories come first. This is useful when |
627 | order where likely directories come first, in optimal stat |
485 | you need to quickly find directories, or you want to find all |
628 | order. This is useful when you need to quickly find directories, |
486 | directories while avoiding to stat() each entry. |
629 | or you want to find all directories while avoiding to stat() |
|
|
630 | each entry. |
487 | |
631 | |
488 | If the system returns type information in readdir, then this is |
632 | If the system returns type information in readdir, then this is |
489 | used to find directories directly. Otherwise, likely directories |
633 | used to find directories directly. Otherwise, likely directories |
490 | are files beginning with ".", or otherwise files with no dots, |
634 | are names beginning with ".", or otherwise names with no dots, |
491 | of which files with short names are tried first. |
635 | of which names with short names are tried first. |
492 | |
636 | |
493 | IO::AIO::READDIR_STAT_ORDER |
637 | IO::AIO::READDIR_STAT_ORDER |
494 | When this flag is set, then the names will be returned in an |
638 | When this flag is set, then the names will be returned in an |
495 | order suitable for stat()'ing each one. That is, when you plan |
639 | order suitable for stat()'ing each one. That is, when you plan |
496 | to stat() all files in the given directory, then the returned |
640 | to stat() all files in the given directory, then the returned |
… | |
… | |
512 | into memory. Status is the same as with aio_read. |
656 | into memory. Status is the same as with aio_read. |
513 | |
657 | |
514 | aio_copy $srcpath, $dstpath, $callback->($status) |
658 | aio_copy $srcpath, $dstpath, $callback->($status) |
515 | Try to copy the *file* (directories not supported as either source |
659 | Try to copy the *file* (directories not supported as either source |
516 | or destination) from $srcpath to $dstpath and call the callback with |
660 | or destination) from $srcpath to $dstpath and call the callback with |
517 | the 0 (error) or -1 ok. |
661 | a status of 0 (ok) or -1 (error, see $!). |
518 | |
662 | |
519 | This is a composite request that creates the destination file with |
663 | This is a composite request that creates the destination file with |
520 | mode 0200 and copies the contents of the source file into it using |
664 | mode 0200 and copies the contents of the source file into it using |
521 | "aio_sendfile", followed by restoring atime, mtime, access mode and |
665 | "aio_sendfile", followed by restoring atime, mtime, access mode and |
522 | uid/gid, in that order. |
666 | uid/gid, in that order. |
… | |
… | |
526 | uid/gid, where errors are being ignored. |
670 | uid/gid, where errors are being ignored. |
527 | |
671 | |
528 | aio_move $srcpath, $dstpath, $callback->($status) |
672 | aio_move $srcpath, $dstpath, $callback->($status) |
529 | Try to move the *file* (directories not supported as either source |
673 | Try to move the *file* (directories not supported as either source |
530 | or destination) from $srcpath to $dstpath and call the callback with |
674 | or destination) from $srcpath to $dstpath and call the callback with |
531 | the 0 (error) or -1 ok. |
675 | a status of 0 (ok) or -1 (error, see $!). |
532 | |
676 | |
533 | This is a composite request that tries to rename(2) the file first; |
677 | This is a composite request that tries to rename(2) the file first; |
534 | if rename fails with "EXDEV", it copies the file with "aio_copy" |
678 | if rename fails with "EXDEV", it copies the file with "aio_copy" |
535 | and, if that is successful, unlinks the $srcpath. |
679 | and, if that is successful, unlinks the $srcpath. |
536 | |
680 | |
… | |
… | |
631 | operations (E.g. rename). This might not work on all operating |
775 | operations (E.g. rename). This might not work on all operating |
632 | systems or have any specific effect, but usually it makes sure that |
776 | systems or have any specific effect, but usually it makes sure that |
633 | directory changes get written to disc. It works for anything that |
777 | directory changes get written to disc. It works for anything that |
634 | can be opened for read-only, not just directories. |
778 | can be opened for read-only, not just directories. |
635 | |
779 | |
|
|
780 | Future versions of this function might fall back to other methods |
|
|
781 | when "fsync" on the directory fails (such as calling "sync"). |
|
|
782 | |
636 | Passes 0 when everything went ok, and -1 on error. |
783 | Passes 0 when everything went ok, and -1 on error. |
|
|
784 | |
|
|
785 | aio_msync $scalar, $offset = 0, $length = undef, flags = 0, |
|
|
786 | $callback->($status) |
|
|
787 | This is a rather advanced IO::AIO call, which only works on |
|
|
788 | mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it |
|
|
789 | also works on data scalars managed by the Sys::Mmap or Mmap modules, |
|
|
790 | note that the scalar must only be modified in-place while an aio |
|
|
791 | operation is pending on it). |
|
|
792 | |
|
|
793 | It calls the "msync" function of your OS, if available, with the |
|
|
794 | memory area starting at $offset in the string and ending $length |
|
|
795 | bytes later. If $length is negative, counts from the end, and if |
|
|
796 | $length is "undef", then it goes till the end of the string. The |
|
|
797 | flags can be a combination of "IO::AIO::MS_ASYNC", |
|
|
798 | "IO::AIO::MS_INVALIDATE" and "IO::AIO::MS_SYNC". |
|
|
799 | |
|
|
800 | aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, |
|
|
801 | $callback->($status) |
|
|
802 | This is a rather advanced IO::AIO call, which works best on |
|
|
803 | mmap(2)ed scalars. |
|
|
804 | |
|
|
805 | It touches (reads or writes) all memory pages in the specified range |
|
|
806 | inside the scalar. All caveats and parameters are the same as for |
|
|
807 | "aio_msync", above, except for flags, which must be either 0 (which |
|
|
808 | reads all pages and ensures they are instantiated) or |
|
|
809 | "IO::AIO::MT_MODIFY", which modifies the memory page s(by reading |
|
|
810 | and writing an octet from it, which dirties the page). |
|
|
811 | |
|
|
812 | aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
|
|
813 | This is a rather advanced IO::AIO call, which works best on |
|
|
814 | mmap(2)ed scalars. |
|
|
815 | |
|
|
816 | It reads in all the pages of the underlying storage into memory (if |
|
|
817 | any) and locks them, so they are not getting swapped/paged out or |
|
|
818 | removed. |
|
|
819 | |
|
|
820 | If $length is undefined, then the scalar will be locked till the |
|
|
821 | end. |
|
|
822 | |
|
|
823 | On systems that do not implement "mlock", this function returns -1 |
|
|
824 | and sets errno to "ENOSYS". |
|
|
825 | |
|
|
826 | Note that the corresponding "munlock" is synchronous and is |
|
|
827 | documented under "MISCELLANEOUS FUNCTIONS". |
|
|
828 | |
|
|
829 | Example: open a file, mmap and mlock it - both will be undone when |
|
|
830 | $data gets destroyed. |
|
|
831 | |
|
|
832 | open my $fh, "<", $path or die "$path: $!"; |
|
|
833 | my $data; |
|
|
834 | IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; |
|
|
835 | aio_mlock $data; # mlock in background |
|
|
836 | |
|
|
837 | aio_mlockall $flags, $callback->($status) |
|
|
838 | Calls the "mlockall" function with the given $flags (a combination |
|
|
839 | of "IO::AIO::MCL_CURRENT" and "IO::AIO::MCL_FUTURE"). |
|
|
840 | |
|
|
841 | On systems that do not implement "mlockall", this function returns |
|
|
842 | -1 and sets errno to "ENOSYS". |
|
|
843 | |
|
|
844 | Note that the corresponding "munlockall" is synchronous and is |
|
|
845 | documented under "MISCELLANEOUS FUNCTIONS". |
|
|
846 | |
|
|
847 | Example: asynchronously lock all current and future pages into |
|
|
848 | memory. |
|
|
849 | |
|
|
850 | aio_mlockall IO::AIO::MCL_FUTURE; |
637 | |
851 | |
638 | aio_group $callback->(...) |
852 | aio_group $callback->(...) |
639 | This is a very special aio request: Instead of doing something, it |
853 | This is a very special aio request: Instead of doing something, it |
640 | is a container for other aio requests, which is useful if you want |
854 | is a container for other aio requests, which is useful if you want |
641 | to bundle many requests into a single, composite, request with a |
855 | to bundle many requests into a single, composite, request with a |
… | |
… | |
684 | |
898 | |
685 | cancel $req |
899 | cancel $req |
686 | Cancels the request, if possible. Has the effect of skipping |
900 | Cancels the request, if possible. Has the effect of skipping |
687 | execution when entering the execute state and skipping calling the |
901 | execution when entering the execute state and skipping calling the |
688 | callback when entering the the result state, but will leave the |
902 | callback when entering the the result state, but will leave the |
689 | request otherwise untouched. That means that requests that currently |
903 | request otherwise untouched (with the exception of readdir). That |
690 | execute will not be stopped and resources held by the request will |
904 | means that requests that currently execute will not be stopped and |
691 | not be freed prematurely. |
905 | resources held by the request will not be freed prematurely. |
692 | |
906 | |
693 | cb $req $callback->(...) |
907 | cb $req $callback->(...) |
694 | Replace (or simply set) the callback registered to the request. |
908 | Replace (or simply set) the callback registered to the request. |
695 | |
909 | |
696 | IO::AIO::GRP CLASS |
910 | IO::AIO::GRP CLASS |
… | |
… | |
757 | |
971 | |
758 | $grp->cancel_subs |
972 | $grp->cancel_subs |
759 | Cancel all subrequests and clears any feeder, but not the group |
973 | Cancel all subrequests and clears any feeder, but not the group |
760 | request itself. Useful when you queued a lot of events but got a |
974 | request itself. Useful when you queued a lot of events but got a |
761 | result early. |
975 | result early. |
|
|
976 | |
|
|
977 | The group request will finish normally (you cannot add requests to |
|
|
978 | the group). |
762 | |
979 | |
763 | $grp->result (...) |
980 | $grp->result (...) |
764 | Set the result value(s) that will be passed to the group callback |
981 | Set the result value(s) that will be passed to the group callback |
765 | when all subrequests have finished and set the groups errno to the |
982 | when all subrequests have finished and set the groups errno to the |
766 | current value of errno (just like calling "errno" without an error |
983 | current value of errno (just like calling "errno" without an error |
… | |
… | |
826 | SUPPORT FUNCTIONS |
1043 | SUPPORT FUNCTIONS |
827 | EVENT PROCESSING AND EVENT LOOP INTEGRATION |
1044 | EVENT PROCESSING AND EVENT LOOP INTEGRATION |
828 | $fileno = IO::AIO::poll_fileno |
1045 | $fileno = IO::AIO::poll_fileno |
829 | Return the *request result pipe file descriptor*. This filehandle |
1046 | Return the *request result pipe file descriptor*. This filehandle |
830 | must be polled for reading by some mechanism outside this module |
1047 | must be polled for reading by some mechanism outside this module |
831 | (e.g. Event or select, see below or the SYNOPSIS). If the pipe |
1048 | (e.g. EV, Glib, select and so on, see below or the SYNOPSIS). If the |
832 | becomes readable you have to call "poll_cb" to check the results. |
1049 | pipe becomes readable you have to call "poll_cb" to check the |
|
|
1050 | results. |
833 | |
1051 | |
834 | See "poll_cb" for an example. |
1052 | See "poll_cb" for an example. |
835 | |
1053 | |
836 | IO::AIO::poll_cb |
1054 | IO::AIO::poll_cb |
837 | Process some outstanding events on the result pipe. You have to call |
1055 | Process some outstanding events on the result pipe. You have to call |
838 | this regularly. Returns 0 if all events could be processed, or -1 if |
1056 | this regularly. Returns 0 if all events could be processed (or there |
839 | it returned earlier for whatever reason. Returns immediately when no |
1057 | were no events to process), or -1 if it returned earlier for |
840 | events are outstanding. The amount of events processed depends on |
1058 | whatever reason. Returns immediately when no events are outstanding. |
841 | the settings of "IO::AIO::max_poll_req" and |
1059 | The amount of events processed depends on the settings of |
842 | "IO::AIO::max_poll_time". |
1060 | "IO::AIO::max_poll_req" and "IO::AIO::max_poll_time". |
843 | |
1061 | |
844 | If not all requests were processed for whatever reason, the |
1062 | If not all requests were processed for whatever reason, the |
845 | filehandle will still be ready when "poll_cb" returns, so normally |
1063 | filehandle will still be ready when "poll_cb" returns, so normally |
846 | you don't have to do anything special to have it called later. |
1064 | you don't have to do anything special to have it called later. |
847 | |
1065 | |
|
|
1066 | Apart from calling "IO::AIO::poll_cb" when the event filehandle |
|
|
1067 | becomes ready, it can be beneficial to call this function from loops |
|
|
1068 | which submit a lot of requests, to make sure the results get |
|
|
1069 | processed when they become available and not just when the loop is |
|
|
1070 | finished and the event loop takes over again. This function returns |
|
|
1071 | very fast when there are no outstanding requests. |
|
|
1072 | |
848 | Example: Install an Event watcher that automatically calls |
1073 | Example: Install an Event watcher that automatically calls |
849 | IO::AIO::poll_cb with high priority: |
1074 | IO::AIO::poll_cb with high priority (more examples can be found in |
|
|
1075 | the SYNOPSIS section, at the top of this document): |
850 | |
1076 | |
851 | Event->io (fd => IO::AIO::poll_fileno, |
1077 | Event->io (fd => IO::AIO::poll_fileno, |
852 | poll => 'r', async => 1, |
1078 | poll => 'r', async => 1, |
853 | cb => \&IO::AIO::poll_cb); |
1079 | cb => \&IO::AIO::poll_cb); |
|
|
1080 | |
|
|
1081 | IO::AIO::poll_wait |
|
|
1082 | If there are any outstanding requests and none of them in the result |
|
|
1083 | phase, wait till the result filehandle becomes ready for reading |
|
|
1084 | (simply does a "select" on the filehandle. This is useful if you |
|
|
1085 | want to synchronously wait for some requests to finish). |
|
|
1086 | |
|
|
1087 | See "nreqs" for an example. |
|
|
1088 | |
|
|
1089 | IO::AIO::poll |
|
|
1090 | Waits until some requests have been handled. |
|
|
1091 | |
|
|
1092 | Returns the number of requests processed, but is otherwise strictly |
|
|
1093 | equivalent to: |
|
|
1094 | |
|
|
1095 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1096 | |
|
|
1097 | IO::AIO::flush |
|
|
1098 | Wait till all outstanding AIO requests have been handled. |
|
|
1099 | |
|
|
1100 | Strictly equivalent to: |
|
|
1101 | |
|
|
1102 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1103 | while IO::AIO::nreqs; |
854 | |
1104 | |
855 | IO::AIO::max_poll_reqs $nreqs |
1105 | IO::AIO::max_poll_reqs $nreqs |
856 | IO::AIO::max_poll_time $seconds |
1106 | IO::AIO::max_poll_time $seconds |
857 | These set the maximum number of requests (default 0, meaning |
1107 | These set the maximum number of requests (default 0, meaning |
858 | infinity) that are being processed by "IO::AIO::poll_cb" in one |
1108 | infinity) that are being processed by "IO::AIO::poll_cb" in one |
… | |
… | |
882 | # use a low priority so other tasks have priority |
1132 | # use a low priority so other tasks have priority |
883 | Event->io (fd => IO::AIO::poll_fileno, |
1133 | Event->io (fd => IO::AIO::poll_fileno, |
884 | poll => 'r', nice => 1, |
1134 | poll => 'r', nice => 1, |
885 | cb => &IO::AIO::poll_cb); |
1135 | cb => &IO::AIO::poll_cb); |
886 | |
1136 | |
887 | IO::AIO::poll_wait |
|
|
888 | If there are any outstanding requests and none of them in the result |
|
|
889 | phase, wait till the result filehandle becomes ready for reading |
|
|
890 | (simply does a "select" on the filehandle. This is useful if you |
|
|
891 | want to synchronously wait for some requests to finish). |
|
|
892 | |
|
|
893 | See "nreqs" for an example. |
|
|
894 | |
|
|
895 | IO::AIO::poll |
|
|
896 | Waits until some requests have been handled. |
|
|
897 | |
|
|
898 | Returns the number of requests processed, but is otherwise strictly |
|
|
899 | equivalent to: |
|
|
900 | |
|
|
901 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
902 | |
|
|
903 | IO::AIO::flush |
|
|
904 | Wait till all outstanding AIO requests have been handled. |
|
|
905 | |
|
|
906 | Strictly equivalent to: |
|
|
907 | |
|
|
908 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
909 | while IO::AIO::nreqs; |
|
|
910 | |
|
|
911 | CONTROLLING THE NUMBER OF THREADS |
1137 | CONTROLLING THE NUMBER OF THREADS |
912 | IO::AIO::min_parallel $nthreads |
1138 | IO::AIO::min_parallel $nthreads |
913 | Set the minimum number of AIO threads to $nthreads. The current |
1139 | Set the minimum number of AIO threads to $nthreads. The current |
914 | default is 8, which means eight asynchronous operations can execute |
1140 | default is 8, which means eight asynchronous operations can execute |
915 | concurrently at any one time (the number of outstanding requests, |
1141 | concurrently at any one time (the number of outstanding requests, |
… | |
… | |
944 | |
1170 | |
945 | Under normal circumstances you don't need to call this function. |
1171 | Under normal circumstances you don't need to call this function. |
946 | |
1172 | |
947 | IO::AIO::max_idle $nthreads |
1173 | IO::AIO::max_idle $nthreads |
948 | Limit the number of threads (default: 4) that are allowed to idle |
1174 | Limit the number of threads (default: 4) that are allowed to idle |
949 | (i.e., threads that did not get a request to process within 10 |
1175 | (i.e., threads that did not get a request to process within the idle |
950 | seconds). That means if a thread becomes idle while $nthreads other |
1176 | timeout (default: 10 seconds). That means if a thread becomes idle |
951 | threads are also idle, it will free its resources and exit. |
1177 | while $nthreads other threads are also idle, it will free its |
|
|
1178 | resources and exit. |
952 | |
1179 | |
953 | This is useful when you allow a large number of threads (e.g. 100 or |
1180 | This is useful when you allow a large number of threads (e.g. 100 or |
954 | 1000) to allow for extremely high load situations, but want to free |
1181 | 1000) to allow for extremely high load situations, but want to free |
955 | resources under normal circumstances (1000 threads can easily |
1182 | resources under normal circumstances (1000 threads can easily |
956 | consume 30MB of RAM). |
1183 | consume 30MB of RAM). |
957 | |
1184 | |
958 | The default is probably ok in most situations, especially if thread |
1185 | The default is probably ok in most situations, especially if thread |
959 | creation is fast. If thread creation is very slow on your system you |
1186 | creation is fast. If thread creation is very slow on your system you |
960 | might want to use larger values. |
1187 | might want to use larger values. |
961 | |
1188 | |
|
|
1189 | IO::AIO::idle_timeout $seconds |
|
|
1190 | Sets the minimum idle timeout (default 10) after which worker |
|
|
1191 | threads are allowed to exit. SEe "IO::AIO::max_idle". |
|
|
1192 | |
962 | IO::AIO::max_outstanding $maxreqs |
1193 | IO::AIO::max_outstanding $maxreqs |
|
|
1194 | Sets the maximum number of outstanding requests to $nreqs. If you do |
|
|
1195 | queue up more than this number of requests, the next call to |
|
|
1196 | "IO::AIO::poll_cb" (and other functions calling "poll_cb", such as |
|
|
1197 | "IO::AIO::flush" or "IO::AIO::poll") will block until the limit is |
|
|
1198 | no longer exceeded. |
|
|
1199 | |
|
|
1200 | In other words, this setting does not enforce a queue limit, but can |
|
|
1201 | be used to make poll functions block if the limit is exceeded. |
|
|
1202 | |
963 | This is a very bad function to use in interactive programs because |
1203 | This is a very bad function to use in interactive programs because |
964 | it blocks, and a bad way to reduce concurrency because it is |
1204 | it blocks, and a bad way to reduce concurrency because it is |
965 | inexact: Better use an "aio_group" together with a feed callback. |
1205 | inexact: Better use an "aio_group" together with a feed callback. |
966 | |
1206 | |
967 | Sets the maximum number of outstanding requests to $nreqs. If you do |
1207 | It's main use is in scripts without an event loop - when you want to |
968 | queue up more than this number of requests, the next call to the |
1208 | stat a lot of files, you can write somehting like this: |
969 | "poll_cb" (and "poll_some" and other functions calling "poll_cb") |
|
|
970 | function will block until the limit is no longer exceeded. |
|
|
971 | |
1209 | |
972 | The default value is very large, so there is no practical limit on |
1210 | IO::AIO::max_outstanding 32; |
|
|
1211 | |
|
|
1212 | for my $path (...) { |
|
|
1213 | aio_stat $path , ...; |
|
|
1214 | IO::AIO::poll_cb; |
|
|
1215 | } |
|
|
1216 | |
|
|
1217 | IO::AIO::flush; |
|
|
1218 | |
|
|
1219 | The call to "poll_cb" inside the loop will normally return |
|
|
1220 | instantly, but as soon as more thna 32 reqeusts are in-flight, it |
|
|
1221 | will block until some requests have been handled. This keeps the |
|
|
1222 | loop from pushing a large number of "aio_stat" requests onto the |
|
|
1223 | queue. |
|
|
1224 | |
|
|
1225 | The default value for "max_outstanding" is very large, so there is |
973 | the number of outstanding requests. |
1226 | no practical limit on the number of outstanding requests. |
974 | |
|
|
975 | You can still queue as many requests as you want. Therefore, |
|
|
976 | "max_outstanding" is mainly useful in simple scripts (with low |
|
|
977 | values) or as a stop gap to shield against fatal memory overflow |
|
|
978 | (with large values). |
|
|
979 | |
1227 | |
980 | STATISTICAL INFORMATION |
1228 | STATISTICAL INFORMATION |
981 | IO::AIO::nreqs |
1229 | IO::AIO::nreqs |
982 | Returns the number of requests currently in the ready, execute or |
1230 | Returns the number of requests currently in the ready, execute or |
983 | pending states (i.e. for which their callback has not been invoked |
1231 | pending states (i.e. for which their callback has not been invoked |
… | |
… | |
994 | |
1242 | |
995 | IO::AIO::npending |
1243 | IO::AIO::npending |
996 | Returns the number of requests currently in the pending state |
1244 | Returns the number of requests currently in the pending state |
997 | (executed, but not yet processed by poll_cb). |
1245 | (executed, but not yet processed by poll_cb). |
998 | |
1246 | |
|
|
1247 | MISCELLANEOUS FUNCTIONS |
|
|
1248 | IO::AIO implements some functions that might be useful, but are not |
|
|
1249 | asynchronous. |
|
|
1250 | |
|
|
1251 | IO::AIO::sendfile $ofh, $ifh, $offset, $count |
|
|
1252 | Calls the "eio_sendfile_sync" function, which is like |
|
|
1253 | "aio_sendfile", but is blocking (this makes most sense if you know |
|
|
1254 | the input data is likely cached already and the output filehandle is |
|
|
1255 | set to non-blocking operations). |
|
|
1256 | |
|
|
1257 | Returns the number of bytes copied, or -1 on error. |
|
|
1258 | |
|
|
1259 | IO::AIO::fadvise $fh, $offset, $len, $advice |
|
|
1260 | Simply calls the "posix_fadvise" function (see its manpage for |
|
|
1261 | details). The following advice constants are avaiable: |
|
|
1262 | "IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL", |
|
|
1263 | "IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE", |
|
|
1264 | "IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED". |
|
|
1265 | |
|
|
1266 | On systems that do not implement "posix_fadvise", this function |
|
|
1267 | returns ENOSYS, otherwise the return value of "posix_fadvise". |
|
|
1268 | |
|
|
1269 | IO::AIO::madvise $scalar, $offset, $len, $advice |
|
|
1270 | Simply calls the "posix_madvise" function (see its manpage for |
|
|
1271 | details). The following advice constants are avaiable: |
|
|
1272 | "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL", |
|
|
1273 | "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED", |
|
|
1274 | "IO::AIO::MADV_DONTNEED". |
|
|
1275 | |
|
|
1276 | On systems that do not implement "posix_madvise", this function |
|
|
1277 | returns ENOSYS, otherwise the return value of "posix_madvise". |
|
|
1278 | |
|
|
1279 | IO::AIO::mprotect $scalar, $offset, $len, $protect |
|
|
1280 | Simply calls the "mprotect" function on the preferably AIO::mmap'ed |
|
|
1281 | $scalar (see its manpage for details). The following protect |
|
|
1282 | constants are avaiable: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ", |
|
|
1283 | "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC". |
|
|
1284 | |
|
|
1285 | On systems that do not implement "mprotect", this function returns |
|
|
1286 | ENOSYS, otherwise the return value of "mprotect". |
|
|
1287 | |
|
|
1288 | IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] |
|
|
1289 | Memory-maps a file (or anonymous memory range) and attaches it to |
|
|
1290 | the given $scalar, which will act like a string scalar. |
|
|
1291 | |
|
|
1292 | The only operations allowed on the scalar are "substr"/"vec" that |
|
|
1293 | don't change the string length, and most read-only operations such |
|
|
1294 | as copying it or searching it with regexes and so on. |
|
|
1295 | |
|
|
1296 | Anything else is unsafe and will, at best, result in memory leaks. |
|
|
1297 | |
|
|
1298 | The memory map associated with the $scalar is automatically removed |
|
|
1299 | when the $scalar is destroyed, or when the "IO::AIO::mmap" or |
|
|
1300 | "IO::AIO::munmap" functions are called. |
|
|
1301 | |
|
|
1302 | This calls the "mmap"(2) function internally. See your system's |
|
|
1303 | manual page for details on the $length, $prot and $flags parameters. |
|
|
1304 | |
|
|
1305 | The $length must be larger than zero and smaller than the actual |
|
|
1306 | filesize. |
|
|
1307 | |
|
|
1308 | $prot is a combination of "IO::AIO::PROT_NONE", |
|
|
1309 | "IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or |
|
|
1310 | "IO::AIO::PROT_WRITE", |
|
|
1311 | |
|
|
1312 | $flags can be a combination of "IO::AIO::MAP_SHARED" or |
|
|
1313 | "IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when |
|
|
1314 | not available, the are defined as 0): "IO::AIO::MAP_ANONYMOUS" |
|
|
1315 | (which is set to "MAP_ANON" if your system only provides this |
|
|
1316 | constant), "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED", |
|
|
1317 | "IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE" or |
|
|
1318 | "IO::AIO::MAP_NONBLOCK" |
|
|
1319 | |
|
|
1320 | If $fh is "undef", then a file descriptor of -1 is passed. |
|
|
1321 | |
|
|
1322 | $offset is the offset from the start of the file - it generally must |
|
|
1323 | be a multiple of "IO::AIO::PAGESIZE" and defaults to 0. |
|
|
1324 | |
|
|
1325 | Example: |
|
|
1326 | |
|
|
1327 | use Digest::MD5; |
|
|
1328 | use IO::AIO; |
|
|
1329 | |
|
|
1330 | open my $fh, "<verybigfile" |
|
|
1331 | or die "$!"; |
|
|
1332 | |
|
|
1333 | IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh |
|
|
1334 | or die "verybigfile: $!"; |
|
|
1335 | |
|
|
1336 | my $fast_md5 = md5 $data; |
|
|
1337 | |
|
|
1338 | IO::AIO::munmap $scalar |
|
|
1339 | Removes a previous mmap and undefines the $scalar. |
|
|
1340 | |
|
|
1341 | IO::AIO::munlock $scalar, $offset = 0, $length = undef |
|
|
1342 | Calls the "munlock" function, undoing the effects of a previous |
|
|
1343 | "aio_mlock" call (see its description for details). |
|
|
1344 | |
|
|
1345 | IO::AIO::munlockall |
|
|
1346 | Calls the "munlockall" function. |
|
|
1347 | |
|
|
1348 | On systems that do not implement "munlockall", this function returns |
|
|
1349 | ENOSYS, otherwise the return value of "munlockall". |
|
|
1350 | |
|
|
1351 | EVENT LOOP INTEGRATION |
|
|
1352 | It is recommended to use AnyEvent::AIO to integrate IO::AIO |
|
|
1353 | automatically into many event loops: |
|
|
1354 | |
|
|
1355 | # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) |
|
|
1356 | use AnyEvent::AIO; |
|
|
1357 | |
|
|
1358 | You can also integrate IO::AIO manually into many event loops, here are |
|
|
1359 | some examples of how to do this: |
|
|
1360 | |
|
|
1361 | # EV integration |
|
|
1362 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
|
|
1363 | |
|
|
1364 | # Event integration |
|
|
1365 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
1366 | poll => 'r', |
|
|
1367 | cb => \&IO::AIO::poll_cb); |
|
|
1368 | |
|
|
1369 | # Glib/Gtk2 integration |
|
|
1370 | add_watch Glib::IO IO::AIO::poll_fileno, |
|
|
1371 | in => sub { IO::AIO::poll_cb; 1 }; |
|
|
1372 | |
|
|
1373 | # Tk integration |
|
|
1374 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
|
|
1375 | readable => \&IO::AIO::poll_cb); |
|
|
1376 | |
|
|
1377 | # Danga::Socket integration |
|
|
1378 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
|
|
1379 | \&IO::AIO::poll_cb); |
|
|
1380 | |
999 | FORK BEHAVIOUR |
1381 | FORK BEHAVIOUR |
1000 | This module should do "the right thing" when the process using it forks: |
1382 | Usage of pthreads in a program changes the semantics of fork |
|
|
1383 | considerably. Specifically, only async-safe functions can be called |
|
|
1384 | after fork. Perl doesn't know about this, so in general, you cannot call |
|
|
1385 | fork with defined behaviour in perl if pthreads are involved. IO::AIO |
|
|
1386 | uses pthreads, so this applies, but many other extensions and (for |
|
|
1387 | inexplicable reasons) perl itself often is linked against pthreads, so |
|
|
1388 | this limitation applies to quite a lot of perls. |
1001 | |
1389 | |
1002 | Before the fork, IO::AIO enters a quiescent state where no requests can |
1390 | This module no longer tries to fight your OS, or POSIX. That means |
1003 | be added in other threads and no results will be processed. After the |
1391 | IO::AIO only works in the process that loaded it. Forking is fully |
1004 | fork the parent simply leaves the quiescent state and continues |
1392 | supported, but using IO::AIO in the child is not. |
1005 | request/result processing, while the child frees the request/result |
|
|
1006 | queue (so that the requests started before the fork will only be handled |
|
|
1007 | in the parent). Threads will be started on demand until the limit set in |
|
|
1008 | the parent process has been reached again. |
|
|
1009 | |
1393 | |
1010 | In short: the parent will, after a short pause, continue as if fork had |
1394 | You might get around by not *using* IO::AIO before (or after) forking. |
1011 | not been called, while the child will act as if IO::AIO has not been |
1395 | You could also try to call the IO::AIO::reinit function in the child: |
1012 | used yet. |
1396 | |
|
|
1397 | IO::AIO::reinit |
|
|
1398 | Abondons all current requests and I/O threads and simply |
|
|
1399 | reinitialises all data structures. This is not an operation |
|
|
1400 | suppported by any standards, but happens to work on GNU/Linux and |
|
|
1401 | some newer BSD systems. |
|
|
1402 | |
|
|
1403 | The only reasonable use for this function is to call it after |
|
|
1404 | forking, if "IO::AIO" was used in the parent. Calling it while |
|
|
1405 | IO::AIO is active in the process will result in undefined behaviour. |
|
|
1406 | Calling it at any time will also result in any undefined (by POSIX) |
|
|
1407 | behaviour. |
1013 | |
1408 | |
1014 | MEMORY USAGE |
1409 | MEMORY USAGE |
1015 | Per-request usage: |
1410 | Per-request usage: |
1016 | |
1411 | |
1017 | Each aio request uses - depending on your architecture - around 100-200 |
1412 | Each aio request uses - depending on your architecture - around 100-200 |