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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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23 | my $req = aio_unlink "/tmp/file", sub { }; |
23 | my $req = aio_unlink "/tmp/file", sub { }; |
24 | $req->cancel; # cancel request if still in queue |
24 | $req->cancel; # cancel request if still in queue |
25 | |
25 | |
26 | my $grp = aio_group sub { print "all stats done\n" }; |
26 | my $grp = aio_group sub { print "all stats done\n" }; |
27 | add $grp aio_stat "..." for ...; |
27 | add $grp aio_stat "..." for ...; |
28 | |
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29 | # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) |
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30 | use AnyEvent::AIO; |
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31 | |
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32 | # EV integration |
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33 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
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34 | |
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35 | # Event integration |
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36 | Event->io (fd => IO::AIO::poll_fileno, |
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37 | poll => 'r', |
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38 | cb => \&IO::AIO::poll_cb); |
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39 | |
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40 | # Glib/Gtk2 integration |
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41 | add_watch Glib::IO IO::AIO::poll_fileno, |
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42 | in => sub { IO::AIO::poll_cb; 1 }; |
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43 | |
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44 | # Tk integration |
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45 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
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46 | readable => \&IO::AIO::poll_cb); |
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47 | |
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48 | # Danga::Socket integration |
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49 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
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50 | \&IO::AIO::poll_cb); |
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51 | |
28 | |
52 | DESCRIPTION |
29 | DESCRIPTION |
53 | This module implements asynchronous I/O using whatever means your |
30 | This module implements asynchronous I/O using whatever means your |
54 | operating system supports. It is implemented as an interface to "libeio" |
31 | operating system supports. It is implemented as an interface to "libeio" |
55 | (<http://software.schmorp.de/pkg/libeio.html>). |
32 | (<http://software.schmorp.de/pkg/libeio.html>). |
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95 | |
72 | |
96 | # register the IO::AIO callback with EV |
73 | # register the IO::AIO callback with EV |
97 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
74 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
98 | |
75 | |
99 | # queue the request to open /etc/passwd |
76 | # queue the request to open /etc/passwd |
100 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
77 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
101 | my $fh = shift |
78 | my $fh = shift |
102 | or die "error while opening: $!"; |
79 | or die "error while opening: $!"; |
103 | |
80 | |
104 | # stat'ing filehandles is generally non-blocking |
81 | # stat'ing filehandles is generally non-blocking |
105 | my $size = -s $fh; |
82 | my $size = -s $fh; |
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168 | anymore (except possibly for the Perl object, but its connection to |
145 | anymore (except possibly for the Perl object, but its connection to |
169 | the actual aio request is severed and calling its methods will |
146 | the actual aio request is severed and calling its methods will |
170 | either do nothing or result in a runtime error). |
147 | either do nothing or result in a runtime error). |
171 | |
148 | |
172 | 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_rename $srcpath, $dstpath, $callback->($status) |
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174 | aio_mkdir $pathname, $mode, $callback->($status) |
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175 | aio_rmdir $pathname, $callback->($status) |
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176 | aio_readdir $pathname, $callback->($entries) |
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177 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
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178 | IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST |
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179 | IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN |
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180 | aio_load $path, $data, $callback->($status) |
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181 | aio_copy $srcpath, $dstpath, $callback->($status) |
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182 | aio_move $srcpath, $dstpath, $callback->($status) |
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183 | aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
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184 | aio_rmtree $path, $callback->($status) |
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185 | aio_sync $callback->($status) |
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186 | aio_fsync $fh, $callback->($status) |
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187 | aio_fdatasync $fh, $callback->($status) |
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188 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
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189 | aio_pathsync $path, $callback->($status) |
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190 | aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
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191 | aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
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192 | aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
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193 | aio_mlockall $flags, $callback->($status) |
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194 | aio_group $callback->(...) |
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195 | aio_nop $callback->() |
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196 | |
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197 | $prev_pri = aioreq_pri [$pri] |
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198 | aioreq_nice $pri_adjust |
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199 | |
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200 | IO::AIO::poll_wait |
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201 | IO::AIO::poll_cb |
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202 | IO::AIO::poll |
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203 | IO::AIO::flush |
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204 | IO::AIO::max_poll_reqs $nreqs |
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205 | IO::AIO::max_poll_time $seconds |
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206 | IO::AIO::min_parallel $nthreads |
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207 | IO::AIO::max_parallel $nthreads |
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208 | IO::AIO::max_idle $nthreads |
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209 | IO::AIO::idle_timeout $seconds |
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210 | IO::AIO::max_outstanding $maxreqs |
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211 | IO::AIO::nreqs |
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212 | IO::AIO::nready |
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213 | IO::AIO::npending |
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214 | |
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215 | IO::AIO::sendfile $ofh, $ifh, $offset, $count |
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216 | IO::AIO::fadvise $fh, $offset, $len, $advice |
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217 | IO::AIO::madvise $scalar, $offset, $length, $advice |
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218 | IO::AIO::mprotect $scalar, $offset, $length, $protect |
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219 | IO::AIO::munlock $scalar, $offset = 0, $length = undef |
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220 | IO::AIO::munlockall |
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221 | |
173 | AIO REQUEST FUNCTIONS |
222 | AIO REQUEST FUNCTIONS |
174 | All the "aio_*" calls are more or less thin wrappers around the syscall |
223 | All the "aio_*" calls are more or less thin wrappers around the syscall |
175 | with the same name (sans "aio_"). The arguments are similar or |
224 | with the same name (sans "aio_"). The arguments are similar or |
176 | identical, and they all accept an additional (and optional) $callback |
225 | identical, and they all accept an additional (and optional) $callback |
177 | argument which must be a code reference. This code reference will get |
226 | argument which must be a code reference. This code reference will get |
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248 | will be modified by the umask in effect then the request is being |
297 | will be modified by the umask in effect then the request is being |
249 | executed, so better never change the umask. |
298 | executed, so better never change the umask. |
250 | |
299 | |
251 | Example: |
300 | Example: |
252 | |
301 | |
253 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
302 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
254 | if ($_[0]) { |
303 | if ($_[0]) { |
255 | print "open successful, fh is $_[0]\n"; |
304 | print "open successful, fh is $_[0]\n"; |
256 | ... |
305 | ... |
257 | } else { |
306 | } else { |
258 | die "open failed: $!\n"; |
307 | die "open failed: $!\n"; |
259 | } |
308 | } |
260 | }; |
309 | }; |
261 | |
310 | |
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311 | In addition to all the common open modes/flags ("O_RDONLY", |
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312 | "O_WRONLY", "O_RDWR", "O_CREAT", "O_TRUNC", "O_EXCL" and |
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313 | "O_APPEND"), the following POSIX and non-POSIX constants are |
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314 | available (missing ones on your system are, as usual, 0): |
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315 | |
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316 | "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY", |
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317 | "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY", |
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318 | "O_DSYNC", "O_RSYNC", "O_SYNC" and "O_TTY_INIT". |
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319 | |
262 | aio_close $fh, $callback->($status) |
320 | aio_close $fh, $callback->($status) |
263 | Asynchronously close a file and call the callback with the result |
321 | Asynchronously close a file and call the callback with the result |
264 | code. |
322 | code. |
265 | |
323 | |
266 | Unfortunately, you can't do this to perl. Perl *insists* very |
324 | Unfortunately, you can't do this to perl. Perl *insists* very |
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309 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
367 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
310 | Tries to copy $length bytes from $in_fh to $out_fh. It starts |
368 | Tries to copy $length bytes from $in_fh to $out_fh. It starts |
311 | reading at byte offset $in_offset, and starts writing at the current |
369 | reading at byte offset $in_offset, and starts writing at the current |
312 | file offset of $out_fh. Because of that, it is not safe to issue |
370 | file offset of $out_fh. Because of that, it is not safe to issue |
313 | more than one "aio_sendfile" per $out_fh, as they will interfere |
371 | more than one "aio_sendfile" per $out_fh, as they will interfere |
314 | with each other. |
372 | with each other. The same $in_fh works fine though, as this function |
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373 | does not move or use the file offset of $in_fh. |
315 | |
374 | |
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375 | Please note that "aio_sendfile" can read more bytes from $in_fh than |
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376 | are written, and there is no way to find out how many more bytes |
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377 | have been read from "aio_sendfile" alone, as "aio_sendfile" only |
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378 | provides the number of bytes written to $out_fh. Only if the result |
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379 | value equals $length one can assume that $length bytes have been |
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380 | read. |
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381 | |
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382 | Unlike with other "aio_" functions, it makes a lot of sense to use |
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383 | "aio_sendfile" on non-blocking sockets, as long as one end |
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384 | (typically the $in_fh) is a file - the file I/O will then be |
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385 | asynchronous, while the socket I/O will be non-blocking. Note, |
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386 | however, that you can run into a trap where "aio_sendfile" reads |
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387 | some data with readahead, then fails to write all data, and when the |
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388 | socket is ready the next time, the data in the cache is already |
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389 | lost, forcing "aio_sendfile" to again hit the disk. Explicit |
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390 | "aio_read" + "aio_write" let's you better control resource usage. |
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391 | |
316 | This call tries to make use of a native "sendfile" syscall to |
392 | This call tries to make use of a native "sendfile"-like syscall to |
317 | provide zero-copy operation. For this to work, $out_fh should refer |
393 | provide zero-copy operation. For this to work, $out_fh should refer |
318 | to a socket, and $in_fh should refer to mmap'able file. |
394 | to a socket, and $in_fh should refer to an mmap'able file. |
319 | |
395 | |
320 | If the native sendfile call fails or is not implemented, it will be |
396 | If a native sendfile cannot be found or it fails with "ENOSYS", |
321 | emulated, so you can call "aio_sendfile" on any type of filehandle |
397 | "EINVAL", "ENOTSUP", "EOPNOTSUPP", "EAFNOSUPPORT", "EPROTOTYPE" or |
322 | regardless of the limitations of the operating system. |
398 | "ENOTSOCK", it will be emulated, so you can call "aio_sendfile" on |
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399 | any type of filehandle regardless of the limitations of the |
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400 | operating system. |
323 | |
401 | |
324 | Please note, however, that "aio_sendfile" can read more bytes from |
402 | As native sendfile syscalls (as practically any non-POSIX interface |
325 | $in_fh than are written, and there is no way to find out how many |
403 | hacked together in a hurry to improve benchmark numbers) tend to be |
326 | bytes have been read from "aio_sendfile" alone, as "aio_sendfile" |
404 | rather buggy on many systems, this implementation tries to work |
327 | only provides the number of bytes written to $out_fh. Only if the |
405 | around some known bugs in Linux and FreeBSD kernels (probably |
328 | result value equals $length one can assume that $length bytes have |
406 | others, too), but that might fail, so you really really should check |
329 | been read. |
407 | the return value of "aio_sendfile" - fewre bytes than expected might |
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408 | have been transferred. |
330 | |
409 | |
331 | aio_readahead $fh,$offset,$length, $callback->($retval) |
410 | aio_readahead $fh,$offset,$length, $callback->($retval) |
332 | "aio_readahead" populates the page cache with data from a file so |
411 | "aio_readahead" populates the page cache with data from a file so |
333 | that subsequent reads from that file will not block on disk I/O. The |
412 | that subsequent reads from that file will not block on disk I/O. The |
334 | $offset argument specifies the starting point from which data is to |
413 | $offset argument specifies the starting point from which data is to |
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355 | Currently, the stats are always 64-bit-stats, i.e. instead of |
434 | Currently, the stats are always 64-bit-stats, i.e. instead of |
356 | returning an error when stat'ing a large file, the results will be |
435 | returning an error when stat'ing a large file, the results will be |
357 | silently truncated unless perl itself is compiled with large file |
436 | silently truncated unless perl itself is compiled with large file |
358 | support. |
437 | support. |
359 | |
438 | |
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439 | To help interpret the mode and dev/rdev stat values, IO::AIO offers |
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440 | the following constants and functions (if not implemented, the |
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441 | constants will be 0 and the functions will either "croak" or fall |
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442 | back on traditional behaviour). |
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443 | |
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444 | "S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG", |
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445 | "S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t", |
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446 | "IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor". |
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447 | |
360 | Example: Print the length of /etc/passwd: |
448 | Example: Print the length of /etc/passwd: |
361 | |
449 | |
362 | aio_stat "/etc/passwd", sub { |
450 | aio_stat "/etc/passwd", sub { |
363 | $_[0] and die "stat failed: $!"; |
451 | $_[0] and die "stat failed: $!"; |
364 | print "size is ", -s _, "\n"; |
452 | print "size is ", -s _, "\n"; |
365 | }; |
453 | }; |
366 | |
454 | |
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455 | aio_statvfs $fh_or_path, $callback->($statvfs) |
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456 | Works like the POSIX "statvfs" or "fstatvfs" syscalls, depending on |
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457 | whether a file handle or path was passed. |
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458 | |
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459 | On success, the callback is passed a hash reference with the |
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460 | following members: "bsize", "frsize", "blocks", "bfree", "bavail", |
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461 | "files", "ffree", "favail", "fsid", "flag" and "namemax". On |
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462 | failure, "undef" is passed. |
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463 | |
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464 | The following POSIX IO::AIO::ST_* constants are defined: "ST_RDONLY" |
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465 | and "ST_NOSUID". |
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466 | |
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467 | The following non-POSIX IO::AIO::ST_* flag masks are defined to |
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468 | their correct value when available, or to 0 on systems that do not |
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469 | support them: "ST_NODEV", "ST_NOEXEC", "ST_SYNCHRONOUS", |
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470 | "ST_MANDLOCK", "ST_WRITE", "ST_APPEND", "ST_IMMUTABLE", |
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471 | "ST_NOATIME", "ST_NODIRATIME" and "ST_RELATIME". |
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472 | |
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473 | Example: stat "/wd" and dump out the data if successful. |
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474 | |
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475 | aio_statvfs "/wd", sub { |
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476 | my $f = $_[0] |
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477 | or die "statvfs: $!"; |
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478 | |
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479 | use Data::Dumper; |
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480 | say Dumper $f; |
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481 | }; |
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482 | |
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483 | # result: |
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484 | { |
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485 | bsize => 1024, |
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486 | bfree => 4333064312, |
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487 | blocks => 10253828096, |
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488 | files => 2050765568, |
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489 | flag => 4096, |
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490 | favail => 2042092649, |
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491 | bavail => 4333064312, |
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492 | ffree => 2042092649, |
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493 | namemax => 255, |
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494 | frsize => 1024, |
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495 | fsid => 1810 |
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496 | } |
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497 | |
367 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
498 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
368 | Works like perl's "utime" function (including the special case of |
499 | Works like perl's "utime" function (including the special case of |
369 | $atime and $mtime being undef). Fractional times are supported if |
500 | $atime and $mtime being undef). Fractional times are supported if |
370 | the underlying syscalls support them. |
501 | the underlying syscalls support them. |
371 | |
502 | |
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409 | |
540 | |
410 | The only (POSIX-) portable way of calling this function is: |
541 | The only (POSIX-) portable way of calling this function is: |
411 | |
542 | |
412 | aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
543 | aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
413 | |
544 | |
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545 | See "aio_stat" for info about some potentially helpful extra |
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546 | constants and functions. |
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547 | |
414 | aio_link $srcpath, $dstpath, $callback->($status) |
548 | aio_link $srcpath, $dstpath, $callback->($status) |
415 | Asynchronously create a new link to the existing object at $srcpath |
549 | Asynchronously create a new link to the existing object at $srcpath |
416 | at the path $dstpath and call the callback with the result code. |
550 | at the path $dstpath and call the callback with the result code. |
417 | |
551 | |
418 | aio_symlink $srcpath, $dstpath, $callback->($status) |
552 | aio_symlink $srcpath, $dstpath, $callback->($status) |
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454 | The flags are a combination of the following constants, ORed |
588 | The flags are a combination of the following constants, ORed |
455 | together (the flags will also be passed to the callback, possibly |
589 | together (the flags will also be passed to the callback, possibly |
456 | modified): |
590 | modified): |
457 | |
591 | |
458 | IO::AIO::READDIR_DENTS |
592 | IO::AIO::READDIR_DENTS |
459 | When this flag is off, then the callback gets an arrayref with |
593 | When this flag is off, then the callback gets an arrayref |
460 | of names only (as with "aio_readdir"), otherwise it gets an |
594 | consisting of names only (as with "aio_readdir"), otherwise it |
461 | arrayref with "[$name, $type, $inode]" arrayrefs, each |
595 | gets an arrayref with "[$name, $type, $inode]" arrayrefs, each |
462 | describing a single directory entry in more detail. |
596 | describing a single directory entry in more detail. |
463 | |
597 | |
464 | $name is the name of the entry. |
598 | $name is the name of the entry. |
465 | |
599 | |
466 | $type is one of the "IO::AIO::DT_xxx" constants: |
600 | $type is one of the "IO::AIO::DT_xxx" constants: |
… | |
… | |
479 | unspecified content on systems that do not deliver the inode |
613 | unspecified content on systems that do not deliver the inode |
480 | information. |
614 | information. |
481 | |
615 | |
482 | IO::AIO::READDIR_DIRS_FIRST |
616 | IO::AIO::READDIR_DIRS_FIRST |
483 | When this flag is set, then the names will be returned in an |
617 | When this flag is set, then the names will be returned in an |
484 | order where likely directories come first. This is useful when |
618 | order where likely directories come first, in optimal stat |
485 | you need to quickly find directories, or you want to find all |
619 | order. This is useful when you need to quickly find directories, |
486 | directories while avoiding to stat() each entry. |
620 | or you want to find all directories while avoiding to stat() |
|
|
621 | each entry. |
487 | |
622 | |
488 | If the system returns type information in readdir, then this is |
623 | If the system returns type information in readdir, then this is |
489 | used to find directories directly. Otherwise, likely directories |
624 | used to find directories directly. Otherwise, likely directories |
490 | are files beginning with ".", or otherwise files with no dots, |
625 | are names beginning with ".", or otherwise names with no dots, |
491 | of which files with short names are tried first. |
626 | of which names with short names are tried first. |
492 | |
627 | |
493 | IO::AIO::READDIR_STAT_ORDER |
628 | IO::AIO::READDIR_STAT_ORDER |
494 | When this flag is set, then the names will be returned in an |
629 | 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 |
630 | order suitable for stat()'ing each one. That is, when you plan |
496 | to stat() all files in the given directory, then the returned |
631 | to stat() all files in the given directory, then the returned |
… | |
… | |
512 | into memory. Status is the same as with aio_read. |
647 | into memory. Status is the same as with aio_read. |
513 | |
648 | |
514 | aio_copy $srcpath, $dstpath, $callback->($status) |
649 | aio_copy $srcpath, $dstpath, $callback->($status) |
515 | Try to copy the *file* (directories not supported as either source |
650 | Try to copy the *file* (directories not supported as either source |
516 | or destination) from $srcpath to $dstpath and call the callback with |
651 | or destination) from $srcpath to $dstpath and call the callback with |
517 | the 0 (error) or -1 ok. |
652 | a status of 0 (ok) or -1 (error, see $!). |
518 | |
653 | |
519 | This is a composite request that creates the destination file with |
654 | 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 |
655 | mode 0200 and copies the contents of the source file into it using |
521 | "aio_sendfile", followed by restoring atime, mtime, access mode and |
656 | "aio_sendfile", followed by restoring atime, mtime, access mode and |
522 | uid/gid, in that order. |
657 | uid/gid, in that order. |
… | |
… | |
526 | uid/gid, where errors are being ignored. |
661 | uid/gid, where errors are being ignored. |
527 | |
662 | |
528 | aio_move $srcpath, $dstpath, $callback->($status) |
663 | aio_move $srcpath, $dstpath, $callback->($status) |
529 | Try to move the *file* (directories not supported as either source |
664 | Try to move the *file* (directories not supported as either source |
530 | or destination) from $srcpath to $dstpath and call the callback with |
665 | or destination) from $srcpath to $dstpath and call the callback with |
531 | the 0 (error) or -1 ok. |
666 | a status of 0 (ok) or -1 (error, see $!). |
532 | |
667 | |
533 | This is a composite request that tries to rename(2) the file first; |
668 | 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" |
669 | if rename fails with "EXDEV", it copies the file with "aio_copy" |
535 | and, if that is successful, unlinks the $srcpath. |
670 | and, if that is successful, unlinks the $srcpath. |
536 | |
671 | |
… | |
… | |
636 | Future versions of this function might fall back to other methods |
771 | Future versions of this function might fall back to other methods |
637 | when "fsync" on the directory fails (such as calling "sync"). |
772 | when "fsync" on the directory fails (such as calling "sync"). |
638 | |
773 | |
639 | Passes 0 when everything went ok, and -1 on error. |
774 | Passes 0 when everything went ok, and -1 on error. |
640 | |
775 | |
|
|
776 | aio_msync $scalar, $offset = 0, $length = undef, flags = 0, |
|
|
777 | $callback->($status) |
|
|
778 | This is a rather advanced IO::AIO call, which only works on |
|
|
779 | mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it |
|
|
780 | also works on data scalars managed by the Sys::Mmap or Mmap modules, |
|
|
781 | note that the scalar must only be modified in-place while an aio |
|
|
782 | operation is pending on it). |
|
|
783 | |
|
|
784 | It calls the "msync" function of your OS, if available, with the |
|
|
785 | memory area starting at $offset in the string and ending $length |
|
|
786 | bytes later. If $length is negative, counts from the end, and if |
|
|
787 | $length is "undef", then it goes till the end of the string. The |
|
|
788 | flags can be a combination of "IO::AIO::MS_ASYNC", |
|
|
789 | "IO::AIO::MS_INVALIDATE" and "IO::AIO::MS_SYNC". |
|
|
790 | |
|
|
791 | aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, |
|
|
792 | $callback->($status) |
|
|
793 | This is a rather advanced IO::AIO call, which works best on |
|
|
794 | mmap(2)ed scalars. |
|
|
795 | |
|
|
796 | It touches (reads or writes) all memory pages in the specified range |
|
|
797 | inside the scalar. All caveats and parameters are the same as for |
|
|
798 | "aio_msync", above, except for flags, which must be either 0 (which |
|
|
799 | reads all pages and ensures they are instantiated) or |
|
|
800 | "IO::AIO::MT_MODIFY", which modifies the memory page s(by reading |
|
|
801 | and writing an octet from it, which dirties the page). |
|
|
802 | |
|
|
803 | aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
|
|
804 | This is a rather advanced IO::AIO call, which works best on |
|
|
805 | mmap(2)ed scalars. |
|
|
806 | |
|
|
807 | It reads in all the pages of the underlying storage into memory (if |
|
|
808 | any) and locks them, so they are not getting swapped/paged out or |
|
|
809 | removed. |
|
|
810 | |
|
|
811 | If $length is undefined, then the scalar will be locked till the |
|
|
812 | end. |
|
|
813 | |
|
|
814 | On systems that do not implement "mlock", this function returns -1 |
|
|
815 | and sets errno to "ENOSYS". |
|
|
816 | |
|
|
817 | Note that the corresponding "munlock" is synchronous and is |
|
|
818 | documented under "MISCELLANEOUS FUNCTIONS". |
|
|
819 | |
|
|
820 | Example: open a file, mmap and mlock it - both will be undone when |
|
|
821 | $data gets destroyed. |
|
|
822 | |
|
|
823 | open my $fh, "<", $path or die "$path: $!"; |
|
|
824 | my $data; |
|
|
825 | IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; |
|
|
826 | aio_mlock $data; # mlock in background |
|
|
827 | |
|
|
828 | aio_mlockall $flags, $callback->($status) |
|
|
829 | Calls the "mlockall" function with the given $flags (a combination |
|
|
830 | of "IO::AIO::MCL_CURRENT" and "IO::AIO::MCL_FUTURE"). |
|
|
831 | |
|
|
832 | On systems that do not implement "mlockall", this function returns |
|
|
833 | -1 and sets errno to "ENOSYS". |
|
|
834 | |
|
|
835 | Note that the corresponding "munlockall" is synchronous and is |
|
|
836 | documented under "MISCELLANEOUS FUNCTIONS". |
|
|
837 | |
|
|
838 | Example: asynchronously lock all current and future pages into |
|
|
839 | memory. |
|
|
840 | |
|
|
841 | aio_mlockall IO::AIO::MCL_FUTURE; |
|
|
842 | |
641 | aio_group $callback->(...) |
843 | aio_group $callback->(...) |
642 | This is a very special aio request: Instead of doing something, it |
844 | This is a very special aio request: Instead of doing something, it |
643 | is a container for other aio requests, which is useful if you want |
845 | is a container for other aio requests, which is useful if you want |
644 | to bundle many requests into a single, composite, request with a |
846 | to bundle many requests into a single, composite, request with a |
645 | definite callback and the ability to cancel the whole request with |
847 | definite callback and the ability to cancel the whole request with |
… | |
… | |
760 | |
962 | |
761 | $grp->cancel_subs |
963 | $grp->cancel_subs |
762 | Cancel all subrequests and clears any feeder, but not the group |
964 | Cancel all subrequests and clears any feeder, but not the group |
763 | request itself. Useful when you queued a lot of events but got a |
965 | request itself. Useful when you queued a lot of events but got a |
764 | result early. |
966 | result early. |
|
|
967 | |
|
|
968 | The group request will finish normally (you cannot add requests to |
|
|
969 | the group). |
765 | |
970 | |
766 | $grp->result (...) |
971 | $grp->result (...) |
767 | Set the result value(s) that will be passed to the group callback |
972 | Set the result value(s) that will be passed to the group callback |
768 | when all subrequests have finished and set the groups errno to the |
973 | when all subrequests have finished and set the groups errno to the |
769 | current value of errno (just like calling "errno" without an error |
974 | current value of errno (just like calling "errno" without an error |
… | |
… | |
837 | |
1042 | |
838 | See "poll_cb" for an example. |
1043 | See "poll_cb" for an example. |
839 | |
1044 | |
840 | IO::AIO::poll_cb |
1045 | IO::AIO::poll_cb |
841 | Process some outstanding events on the result pipe. You have to call |
1046 | Process some outstanding events on the result pipe. You have to call |
842 | this regularly. Returns 0 if all events could be processed, or -1 if |
1047 | this regularly. Returns 0 if all events could be processed (or there |
843 | it returned earlier for whatever reason. Returns immediately when no |
1048 | were no events to process), or -1 if it returned earlier for |
844 | events are outstanding. The amount of events processed depends on |
1049 | whatever reason. Returns immediately when no events are outstanding. |
845 | the settings of "IO::AIO::max_poll_req" and |
1050 | The amount of events processed depends on the settings of |
846 | "IO::AIO::max_poll_time". |
1051 | "IO::AIO::max_poll_req" and "IO::AIO::max_poll_time". |
847 | |
1052 | |
848 | If not all requests were processed for whatever reason, the |
1053 | If not all requests were processed for whatever reason, the |
849 | filehandle will still be ready when "poll_cb" returns, so normally |
1054 | filehandle will still be ready when "poll_cb" returns, so normally |
850 | you don't have to do anything special to have it called later. |
1055 | you don't have to do anything special to have it called later. |
851 | |
1056 | |
|
|
1057 | Apart from calling "IO::AIO::poll_cb" when the event filehandle |
|
|
1058 | becomes ready, it can be beneficial to call this function from loops |
|
|
1059 | which submit a lot of requests, to make sure the results get |
|
|
1060 | processed when they become available and not just when the loop is |
|
|
1061 | finished and the event loop takes over again. This function returns |
|
|
1062 | very fast when there are no outstanding requests. |
|
|
1063 | |
852 | Example: Install an Event watcher that automatically calls |
1064 | Example: Install an Event watcher that automatically calls |
853 | IO::AIO::poll_cb with high priority (more examples can be found in |
1065 | IO::AIO::poll_cb with high priority (more examples can be found in |
854 | the SYNOPSIS section, at the top of this document): |
1066 | the SYNOPSIS section, at the top of this document): |
855 | |
1067 | |
856 | Event->io (fd => IO::AIO::poll_fileno, |
1068 | Event->io (fd => IO::AIO::poll_fileno, |
857 | poll => 'r', async => 1, |
1069 | poll => 'r', async => 1, |
858 | cb => \&IO::AIO::poll_cb); |
1070 | cb => \&IO::AIO::poll_cb); |
|
|
1071 | |
|
|
1072 | IO::AIO::poll_wait |
|
|
1073 | If there are any outstanding requests and none of them in the result |
|
|
1074 | phase, wait till the result filehandle becomes ready for reading |
|
|
1075 | (simply does a "select" on the filehandle. This is useful if you |
|
|
1076 | want to synchronously wait for some requests to finish). |
|
|
1077 | |
|
|
1078 | See "nreqs" for an example. |
|
|
1079 | |
|
|
1080 | IO::AIO::poll |
|
|
1081 | Waits until some requests have been handled. |
|
|
1082 | |
|
|
1083 | Returns the number of requests processed, but is otherwise strictly |
|
|
1084 | equivalent to: |
|
|
1085 | |
|
|
1086 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1087 | |
|
|
1088 | IO::AIO::flush |
|
|
1089 | Wait till all outstanding AIO requests have been handled. |
|
|
1090 | |
|
|
1091 | Strictly equivalent to: |
|
|
1092 | |
|
|
1093 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1094 | while IO::AIO::nreqs; |
859 | |
1095 | |
860 | IO::AIO::max_poll_reqs $nreqs |
1096 | IO::AIO::max_poll_reqs $nreqs |
861 | IO::AIO::max_poll_time $seconds |
1097 | IO::AIO::max_poll_time $seconds |
862 | These set the maximum number of requests (default 0, meaning |
1098 | These set the maximum number of requests (default 0, meaning |
863 | infinity) that are being processed by "IO::AIO::poll_cb" in one |
1099 | infinity) that are being processed by "IO::AIO::poll_cb" in one |
… | |
… | |
887 | # use a low priority so other tasks have priority |
1123 | # use a low priority so other tasks have priority |
888 | Event->io (fd => IO::AIO::poll_fileno, |
1124 | Event->io (fd => IO::AIO::poll_fileno, |
889 | poll => 'r', nice => 1, |
1125 | poll => 'r', nice => 1, |
890 | cb => &IO::AIO::poll_cb); |
1126 | cb => &IO::AIO::poll_cb); |
891 | |
1127 | |
892 | IO::AIO::poll_wait |
|
|
893 | If there are any outstanding requests and none of them in the result |
|
|
894 | phase, wait till the result filehandle becomes ready for reading |
|
|
895 | (simply does a "select" on the filehandle. This is useful if you |
|
|
896 | want to synchronously wait for some requests to finish). |
|
|
897 | |
|
|
898 | See "nreqs" for an example. |
|
|
899 | |
|
|
900 | IO::AIO::poll |
|
|
901 | Waits until some requests have been handled. |
|
|
902 | |
|
|
903 | Returns the number of requests processed, but is otherwise strictly |
|
|
904 | equivalent to: |
|
|
905 | |
|
|
906 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
907 | |
|
|
908 | IO::AIO::flush |
|
|
909 | Wait till all outstanding AIO requests have been handled. |
|
|
910 | |
|
|
911 | Strictly equivalent to: |
|
|
912 | |
|
|
913 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
914 | while IO::AIO::nreqs; |
|
|
915 | |
|
|
916 | CONTROLLING THE NUMBER OF THREADS |
1128 | CONTROLLING THE NUMBER OF THREADS |
917 | IO::AIO::min_parallel $nthreads |
1129 | IO::AIO::min_parallel $nthreads |
918 | Set the minimum number of AIO threads to $nthreads. The current |
1130 | Set the minimum number of AIO threads to $nthreads. The current |
919 | default is 8, which means eight asynchronous operations can execute |
1131 | default is 8, which means eight asynchronous operations can execute |
920 | concurrently at any one time (the number of outstanding requests, |
1132 | concurrently at any one time (the number of outstanding requests, |
… | |
… | |
949 | |
1161 | |
950 | Under normal circumstances you don't need to call this function. |
1162 | Under normal circumstances you don't need to call this function. |
951 | |
1163 | |
952 | IO::AIO::max_idle $nthreads |
1164 | IO::AIO::max_idle $nthreads |
953 | Limit the number of threads (default: 4) that are allowed to idle |
1165 | Limit the number of threads (default: 4) that are allowed to idle |
954 | (i.e., threads that did not get a request to process within 10 |
1166 | (i.e., threads that did not get a request to process within the idle |
955 | seconds). That means if a thread becomes idle while $nthreads other |
1167 | timeout (default: 10 seconds). That means if a thread becomes idle |
956 | threads are also idle, it will free its resources and exit. |
1168 | while $nthreads other threads are also idle, it will free its |
|
|
1169 | resources and exit. |
957 | |
1170 | |
958 | This is useful when you allow a large number of threads (e.g. 100 or |
1171 | This is useful when you allow a large number of threads (e.g. 100 or |
959 | 1000) to allow for extremely high load situations, but want to free |
1172 | 1000) to allow for extremely high load situations, but want to free |
960 | resources under normal circumstances (1000 threads can easily |
1173 | resources under normal circumstances (1000 threads can easily |
961 | consume 30MB of RAM). |
1174 | consume 30MB of RAM). |
962 | |
1175 | |
963 | The default is probably ok in most situations, especially if thread |
1176 | The default is probably ok in most situations, especially if thread |
964 | creation is fast. If thread creation is very slow on your system you |
1177 | creation is fast. If thread creation is very slow on your system you |
965 | might want to use larger values. |
1178 | might want to use larger values. |
966 | |
1179 | |
|
|
1180 | IO::AIO::idle_timeout $seconds |
|
|
1181 | Sets the minimum idle timeout (default 10) after which worker |
|
|
1182 | threads are allowed to exit. SEe "IO::AIO::max_idle". |
|
|
1183 | |
967 | IO::AIO::max_outstanding $maxreqs |
1184 | IO::AIO::max_outstanding $maxreqs |
|
|
1185 | Sets the maximum number of outstanding requests to $nreqs. If you do |
|
|
1186 | queue up more than this number of requests, the next call to |
|
|
1187 | "IO::AIO::poll_cb" (and other functions calling "poll_cb", such as |
|
|
1188 | "IO::AIO::flush" or "IO::AIO::poll") will block until the limit is |
|
|
1189 | no longer exceeded. |
|
|
1190 | |
|
|
1191 | In other words, this setting does not enforce a queue limit, but can |
|
|
1192 | be used to make poll functions block if the limit is exceeded. |
|
|
1193 | |
968 | This is a very bad function to use in interactive programs because |
1194 | This is a very bad function to use in interactive programs because |
969 | it blocks, and a bad way to reduce concurrency because it is |
1195 | it blocks, and a bad way to reduce concurrency because it is |
970 | inexact: Better use an "aio_group" together with a feed callback. |
1196 | inexact: Better use an "aio_group" together with a feed callback. |
971 | |
1197 | |
972 | Sets the maximum number of outstanding requests to $nreqs. If you do |
1198 | It's main use is in scripts without an event loop - when you want to |
973 | queue up more than this number of requests, the next call to the |
1199 | stat a lot of files, you can write somehting like this: |
974 | "poll_cb" (and "poll_some" and other functions calling "poll_cb") |
|
|
975 | function will block until the limit is no longer exceeded. |
|
|
976 | |
1200 | |
977 | The default value is very large, so there is no practical limit on |
1201 | IO::AIO::max_outstanding 32; |
|
|
1202 | |
|
|
1203 | for my $path (...) { |
|
|
1204 | aio_stat $path , ...; |
|
|
1205 | IO::AIO::poll_cb; |
|
|
1206 | } |
|
|
1207 | |
|
|
1208 | IO::AIO::flush; |
|
|
1209 | |
|
|
1210 | The call to "poll_cb" inside the loop will normally return |
|
|
1211 | instantly, but as soon as more thna 32 reqeusts are in-flight, it |
|
|
1212 | will block until some requests have been handled. This keeps the |
|
|
1213 | loop from pushing a large number of "aio_stat" requests onto the |
|
|
1214 | queue. |
|
|
1215 | |
|
|
1216 | The default value for "max_outstanding" is very large, so there is |
978 | the number of outstanding requests. |
1217 | no practical limit on the number of outstanding requests. |
979 | |
|
|
980 | You can still queue as many requests as you want. Therefore, |
|
|
981 | "max_outstanding" is mainly useful in simple scripts (with low |
|
|
982 | values) or as a stop gap to shield against fatal memory overflow |
|
|
983 | (with large values). |
|
|
984 | |
1218 | |
985 | STATISTICAL INFORMATION |
1219 | STATISTICAL INFORMATION |
986 | IO::AIO::nreqs |
1220 | IO::AIO::nreqs |
987 | Returns the number of requests currently in the ready, execute or |
1221 | Returns the number of requests currently in the ready, execute or |
988 | pending states (i.e. for which their callback has not been invoked |
1222 | pending states (i.e. for which their callback has not been invoked |
… | |
… | |
1012 | set to non-blocking operations). |
1246 | set to non-blocking operations). |
1013 | |
1247 | |
1014 | Returns the number of bytes copied, or -1 on error. |
1248 | Returns the number of bytes copied, or -1 on error. |
1015 | |
1249 | |
1016 | IO::AIO::fadvise $fh, $offset, $len, $advice |
1250 | IO::AIO::fadvise $fh, $offset, $len, $advice |
1017 | Simply calls the "posix_fadvise" function (see it's manpage for |
1251 | Simply calls the "posix_fadvise" function (see its manpage for |
1018 | details). The following advice constants are avaiable: |
1252 | details). The following advice constants are avaiable: |
1019 | "IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL", |
1253 | "IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL", |
1020 | "IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE", |
1254 | "IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE", |
1021 | "IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED". |
1255 | "IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED". |
1022 | |
1256 | |
1023 | On systems that do not implement "posix_fadvise", this function |
1257 | On systems that do not implement "posix_fadvise", this function |
1024 | returns ENOSYS, otherwise the return value of "posix_fadvise". |
1258 | returns ENOSYS, otherwise the return value of "posix_fadvise". |
1025 | |
1259 | |
|
|
1260 | IO::AIO::madvise $scalar, $offset, $len, $advice |
|
|
1261 | Simply calls the "posix_madvise" function (see its manpage for |
|
|
1262 | details). The following advice constants are avaiable: |
|
|
1263 | "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL", |
|
|
1264 | "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED", |
|
|
1265 | "IO::AIO::MADV_DONTNEED". |
|
|
1266 | |
|
|
1267 | On systems that do not implement "posix_madvise", this function |
|
|
1268 | returns ENOSYS, otherwise the return value of "posix_madvise". |
|
|
1269 | |
|
|
1270 | IO::AIO::mprotect $scalar, $offset, $len, $protect |
|
|
1271 | Simply calls the "mprotect" function on the preferably AIO::mmap'ed |
|
|
1272 | $scalar (see its manpage for details). The following protect |
|
|
1273 | constants are avaiable: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ", |
|
|
1274 | "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC". |
|
|
1275 | |
|
|
1276 | On systems that do not implement "mprotect", this function returns |
|
|
1277 | ENOSYS, otherwise the return value of "mprotect". |
|
|
1278 | |
|
|
1279 | IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] |
|
|
1280 | Memory-maps a file (or anonymous memory range) and attaches it to |
|
|
1281 | the given $scalar, which will act like a string scalar. |
|
|
1282 | |
|
|
1283 | The only operations allowed on the scalar are "substr"/"vec" that |
|
|
1284 | don't change the string length, and most read-only operations such |
|
|
1285 | as copying it or searching it with regexes and so on. |
|
|
1286 | |
|
|
1287 | Anything else is unsafe and will, at best, result in memory leaks. |
|
|
1288 | |
|
|
1289 | The memory map associated with the $scalar is automatically removed |
|
|
1290 | when the $scalar is destroyed, or when the "IO::AIO::mmap" or |
|
|
1291 | "IO::AIO::munmap" functions are called. |
|
|
1292 | |
|
|
1293 | This calls the "mmap"(2) function internally. See your system's |
|
|
1294 | manual page for details on the $length, $prot and $flags parameters. |
|
|
1295 | |
|
|
1296 | The $length must be larger than zero and smaller than the actual |
|
|
1297 | filesize. |
|
|
1298 | |
|
|
1299 | $prot is a combination of "IO::AIO::PROT_NONE", |
|
|
1300 | "IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or |
|
|
1301 | "IO::AIO::PROT_WRITE", |
|
|
1302 | |
|
|
1303 | $flags can be a combination of "IO::AIO::MAP_SHARED" or |
|
|
1304 | "IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when |
|
|
1305 | not available, the are defined as 0): "IO::AIO::MAP_ANONYMOUS" |
|
|
1306 | (which is set to "MAP_ANON" if your system only provides this |
|
|
1307 | constant), "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED", |
|
|
1308 | "IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE" or |
|
|
1309 | "IO::AIO::MAP_NONBLOCK" |
|
|
1310 | |
|
|
1311 | If $fh is "undef", then a file descriptor of -1 is passed. |
|
|
1312 | |
|
|
1313 | $offset is the offset from the start of the file - it generally must |
|
|
1314 | be a multiple of "IO::AIO::PAGESIZE" and defaults to 0. |
|
|
1315 | |
|
|
1316 | Example: |
|
|
1317 | |
|
|
1318 | use Digest::MD5; |
|
|
1319 | use IO::AIO; |
|
|
1320 | |
|
|
1321 | open my $fh, "<verybigfile" |
|
|
1322 | or die "$!"; |
|
|
1323 | |
|
|
1324 | IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh |
|
|
1325 | or die "verybigfile: $!"; |
|
|
1326 | |
|
|
1327 | my $fast_md5 = md5 $data; |
|
|
1328 | |
|
|
1329 | IO::AIO::munmap $scalar |
|
|
1330 | Removes a previous mmap and undefines the $scalar. |
|
|
1331 | |
|
|
1332 | IO::AIO::munlock $scalar, $offset = 0, $length = undef |
|
|
1333 | Calls the "munlock" function, undoing the effects of a previous |
|
|
1334 | "aio_mlock" call (see its description for details). |
|
|
1335 | |
|
|
1336 | IO::AIO::munlockall |
|
|
1337 | Calls the "munlockall" function. |
|
|
1338 | |
|
|
1339 | On systems that do not implement "munlockall", this function returns |
|
|
1340 | ENOSYS, otherwise the return value of "munlockall". |
|
|
1341 | |
|
|
1342 | EVENT LOOP INTEGRATION |
|
|
1343 | It is recommended to use AnyEvent::AIO to integrate IO::AIO |
|
|
1344 | automatically into many event loops: |
|
|
1345 | |
|
|
1346 | # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) |
|
|
1347 | use AnyEvent::AIO; |
|
|
1348 | |
|
|
1349 | You can also integrate IO::AIO manually into many event loops, here are |
|
|
1350 | some examples of how to do this: |
|
|
1351 | |
|
|
1352 | # EV integration |
|
|
1353 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
|
|
1354 | |
|
|
1355 | # Event integration |
|
|
1356 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
1357 | poll => 'r', |
|
|
1358 | cb => \&IO::AIO::poll_cb); |
|
|
1359 | |
|
|
1360 | # Glib/Gtk2 integration |
|
|
1361 | add_watch Glib::IO IO::AIO::poll_fileno, |
|
|
1362 | in => sub { IO::AIO::poll_cb; 1 }; |
|
|
1363 | |
|
|
1364 | # Tk integration |
|
|
1365 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
|
|
1366 | readable => \&IO::AIO::poll_cb); |
|
|
1367 | |
|
|
1368 | # Danga::Socket integration |
|
|
1369 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
|
|
1370 | \&IO::AIO::poll_cb); |
|
|
1371 | |
1026 | FORK BEHAVIOUR |
1372 | FORK BEHAVIOUR |
1027 | This module should do "the right thing" when the process using it forks: |
1373 | Usage of pthreads in a program changes the semantics of fork |
|
|
1374 | considerably. Specifically, only async-safe functions can be called |
|
|
1375 | after fork. Perl doesn't know about this, so in general, you cannot call |
|
|
1376 | fork with defined behaviour in perl. IO::AIO uses pthreads, so this |
|
|
1377 | applies, but many other extensions and (for inexplicable reasons) perl |
|
|
1378 | itself often is linked against pthreads, so this limitation applies. |
1028 | |
1379 | |
1029 | Before the fork, IO::AIO enters a quiescent state where no requests can |
1380 | Some operating systems have extensions that allow safe use of fork, and |
1030 | be added in other threads and no results will be processed. After the |
1381 | this module should do "the right thing" on those, and tries on others. |
1031 | fork the parent simply leaves the quiescent state and continues |
1382 | At the time of this writing (2011) only GNU/Linux supports these |
1032 | request/result processing, while the child frees the request/result |
1383 | extensions to POSIX. |
1033 | queue (so that the requests started before the fork will only be handled |
|
|
1034 | in the parent). Threads will be started on demand until the limit set in |
|
|
1035 | the parent process has been reached again. |
|
|
1036 | |
|
|
1037 | In short: the parent will, after a short pause, continue as if fork had |
|
|
1038 | not been called, while the child will act as if IO::AIO has not been |
|
|
1039 | used yet. |
|
|
1040 | |
1384 | |
1041 | MEMORY USAGE |
1385 | MEMORY USAGE |
1042 | Per-request usage: |
1386 | Per-request usage: |
1043 | |
1387 | |
1044 | Each aio request uses - depending on your architecture - around 100-200 |
1388 | Each aio request uses - depending on your architecture - around 100-200 |