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Revision 1.22 by root, Sat Jan 6 02:47:11 2007 UTC vs.
Revision 1.43 by root, Sun Jan 10 23:44:02 2010 UTC

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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
30 open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
31 my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
32
33 # Event integration
34 Event->io (fd => IO::AIO::poll_fileno,
35 poll => 'r',
36 cb => \&IO::AIO::poll_cb);
37
38 # Glib/Gtk2 integration
39 add_watch Glib::IO IO::AIO::poll_fileno,
40 in => sub { IO::AIO::poll_cb; 1 };
41
42 # Tk integration
43 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
44 readable => \&IO::AIO::poll_cb);
45
46 # Danga::Socket integration
47 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
48 \&IO::AIO::poll_cb);
49
50DESCRIPTION 29DESCRIPTION
51 This module implements asynchronous I/O using whatever means your 30 This module implements asynchronous I/O using whatever means your
52 operating system supports. 31 operating system supports. It is implemented as an interface to "libeio"
32 (<http://software.schmorp.de/pkg/libeio.html>).
53 33
54 Asynchronous means that operations that can normally block your program 34 Asynchronous means that operations that can normally block your program
55 (e.g. reading from disk) will be done asynchronously: the operation will 35 (e.g. reading from disk) will be done asynchronously: the operation will
56 still block, but you can do something else in the meantime. This is 36 still block, but you can do something else in the meantime. This is
57 extremely useful for programs that need to stay interactive even when 37 extremely useful for programs that need to stay interactive even when
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61 faster on a RAID volume or over NFS when you do a number of stat 41 faster on a RAID volume or over NFS when you do a number of stat
62 operations concurrently. 42 operations concurrently.
63 43
64 While most of this works on all types of file descriptors (for example 44 While most of this works on all types of file descriptors (for example
65 sockets), using these functions on file descriptors that support 45 sockets), using these functions on file descriptors that support
66 nonblocking operation (again, sockets, pipes etc.) is very inefficient 46 nonblocking operation (again, sockets, pipes etc.) is very inefficient.
67 or might not work (aio_read fails on sockets/pipes/fifos). Use an event
68 loop for that (such as the Event module): IO::AIO will naturally fit 47 Use an event loop for that (such as the EV module): IO::AIO will
69 into such an event loop itself. 48 naturally fit into such an event loop itself.
70 49
71 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
72 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
73 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
74 perl. In the future, this module might make use of the native aio 53 perl. In the future, this module might make use of the native aio
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76 not well-supported or restricted (GNU/Linux doesn't allow them on normal 55 not well-supported or restricted (GNU/Linux doesn't allow them on normal
77 files currently, for example), and they would only support aio_read and 56 files currently, for example), and they would only support aio_read and
78 aio_write, so the remaining functionality would have to be implemented 57 aio_write, so the remaining functionality would have to be implemented
79 using threads anyway. 58 using threads anyway.
80 59
81 Although the module will work with in the presence of other (Perl-) 60 Although the module will work in the presence of other (Perl-) threads,
82 threads, it is currently not reentrant in any way, so use appropriate 61 it is currently not reentrant in any way, so use appropriate locking
83 locking yourself, always call "poll_cb" from within the same thread, or 62 yourself, always call "poll_cb" from within the same thread, or never
84 never call "poll_cb" (or other "aio_" functions) recursively. 63 call "poll_cb" (or other "aio_" functions) recursively.
85 64
86 EXAMPLE 65 EXAMPLE
87 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
88 /etc/passwd asynchronously: 67 asynchronously:
89 68
90 use Fcntl; 69 use Fcntl;
91 use Event; 70 use EV;
92 use IO::AIO; 71 use IO::AIO;
93 72
94 # register the IO::AIO callback with Event 73 # register the IO::AIO callback with EV
95 Event->io (fd => IO::AIO::poll_fileno, 74 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
96 poll => 'r',
97 cb => \&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", O_RDONLY, 0, sub {
101 my $fh = shift 78 my $fh = shift
102 or die "error while opening: $!"; 79 or die "error while opening: $!";
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114 91
115 # file contents now in $contents 92 # file contents now in $contents
116 print $contents; 93 print $contents;
117 94
118 # exit event loop and program 95 # exit event loop and program
119 Event::unloop; 96 EV::unloop;
120 }; 97 };
121 }; 98 };
122 99
123 # possibly queue up other requests, or open GUI windows, 100 # possibly queue up other requests, or open GUI windows,
124 # check for sockets etc. etc. 101 # check for sockets etc. etc.
125 102
126 # process events as long as there are some: 103 # process events as long as there are some:
127 Event::loop; 104 EV::loop;
128 105
129REQUEST ANATOMY AND LIFETIME 106REQUEST ANATOMY AND LIFETIME
130 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
131 not directly visible to Perl. 108 not directly visible to Perl.
132 109
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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
172FUNCTIONS 149FUNCTIONS
150 QUICK OVERVIEW
151 This section simply lists the prototypes of the most important functions
152 for quick reference. See the following sections for function-by-function
153 documentation.
154
155 aio_open $pathname, $flags, $mode, $callback->($fh)
156 aio_close $fh, $callback->($status)
157 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
158 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
159 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
160 aio_readahead $fh,$offset,$length, $callback->($retval)
161 aio_stat $fh_or_path, $callback->($status)
162 aio_lstat $fh, $callback->($status)
163 aio_statvfs $fh_or_path, $callback->($statvfs)
164 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
165 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
166 aio_truncate $fh_or_path, $offset, $callback->($status)
167 aio_chmod $fh_or_path, $mode, $callback->($status)
168 aio_unlink $pathname, $callback->($status)
169 aio_mknod $path, $mode, $dev, $callback->($status)
170 aio_link $srcpath, $dstpath, $callback->($status)
171 aio_symlink $srcpath, $dstpath, $callback->($status)
172 aio_readlink $path, $callback->($link)
173 aio_rename $srcpath, $dstpath, $callback->($status)
174 aio_mkdir $pathname, $mode, $callback->($status)
175 aio_rmdir $pathname, $callback->($status)
176 aio_readdir $pathname, $callback->($entries)
177 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
178 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
179 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
180 aio_load $path, $data, $callback->($status)
181 aio_copy $srcpath, $dstpath, $callback->($status)
182 aio_move $srcpath, $dstpath, $callback->($status)
183 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
184 aio_rmtree $path, $callback->($status)
185 aio_sync $callback->($status)
186 aio_fsync $fh, $callback->($status)
187 aio_fdatasync $fh, $callback->($status)
188 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
189 aio_pathsync $path, $callback->($status)
190 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
191 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
192 aio_group $callback->(...)
193 aio_nop $callback->()
194
195 $prev_pri = aioreq_pri [$pri]
196 aioreq_nice $pri_adjust
197
198 IO::AIO::poll_wait
199 IO::AIO::poll_cb
200 IO::AIO::poll
201 IO::AIO::flush
202 IO::AIO::max_poll_reqs $nreqs
203 IO::AIO::max_poll_time $seconds
204 IO::AIO::min_parallel $nthreads
205 IO::AIO::max_parallel $nthreads
206 IO::AIO::max_idle $nthreads
207 IO::AIO::max_outstanding $maxreqs
208 IO::AIO::nreqs
209 IO::AIO::nready
210 IO::AIO::npending
211
212 IO::AIO::sendfile $ofh, $ifh, $offset, $count
213 IO::AIO::fadvise $fh, $offset, $len, $advice
214 IO::AIO::mlockall $flags
215 IO::AIO::munlockall
216
173 AIO REQUEST FUNCTIONS 217 AIO REQUEST FUNCTIONS
174 All the "aio_*" calls are more or less thin wrappers around the syscall 218 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 219 with the same name (sans "aio_"). The arguments are similar or
176 identical, and they all accept an additional (and optional) $callback 220 identical, and they all accept an additional (and optional) $callback
177 argument which must be a code reference. This code reference will get 221 argument which must be a code reference. This code reference will get
178 called with the syscall return code (e.g. most syscalls return -1 on 222 called with the syscall return code (e.g. most syscalls return -1 on
179 error, unlike perl, which usually delivers "false") as it's sole 223 error, unlike perl, which usually delivers "false") as its sole argument
180 argument when the given syscall has been executed asynchronously. 224 after the given syscall has been executed asynchronously.
181 225
182 All functions expecting a filehandle keep a copy of the filehandle 226 All functions expecting a filehandle keep a copy of the filehandle
183 internally until the request has finished. 227 internally until the request has finished.
184 228
185 All functions return request objects of type IO::AIO::REQ that allow 229 All functions return request objects of type IO::AIO::REQ that allow
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198 the user environment, d) use Glib::filename_from_unicode on unicode 242 the user environment, d) use Glib::filename_from_unicode on unicode
199 filenames or e) use something else to ensure your scalar has the correct 243 filenames or e) use something else to ensure your scalar has the correct
200 contents. 244 contents.
201 245
202 This works, btw. independent of the internal UTF-8 bit, which IO::AIO 246 This works, btw. independent of the internal UTF-8 bit, which IO::AIO
203 handles correctly wether it is set or not. 247 handles correctly whether it is set or not.
204 248
205 $prev_pri = aioreq_pri [$pri] 249 $prev_pri = aioreq_pri [$pri]
206 Returns the priority value that would be used for the next request 250 Returns the priority value that would be used for the next request
207 and, if $pri is given, sets the priority for the next aio request. 251 and, if $pri is given, sets the priority for the next aio request.
208 252
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242 They are the same as used by "sysopen". 286 They are the same as used by "sysopen".
243 287
244 Likewise, $mode specifies the mode of the newly created file, if it 288 Likewise, $mode specifies the mode of the newly created file, if it
245 didn't exist and "O_CREAT" has been given, just like perl's 289 didn't exist and "O_CREAT" has been given, just like perl's
246 "sysopen", except that it is mandatory (i.e. use 0 if you don't 290 "sysopen", except that it is mandatory (i.e. use 0 if you don't
247 create new files, and 0666 or 0777 if you do). 291 create new files, and 0666 or 0777 if you do). Note that the $mode
292 will be modified by the umask in effect then the request is being
293 executed, so better never change the umask.
248 294
249 Example: 295 Example:
250 296
251 aio_open "/etc/passwd", O_RDONLY, 0, sub { 297 aio_open "/etc/passwd", O_RDONLY, 0, sub {
252 if ($_[0]) { 298 if ($_[0]) {
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257 } 303 }
258 }; 304 };
259 305
260 aio_close $fh, $callback->($status) 306 aio_close $fh, $callback->($status)
261 Asynchronously close a file and call the callback with the result 307 Asynchronously close a file and call the callback with the result
262 code. *WARNING:* although accepted, you should not pass in a perl 308 code.
263 filehandle here, as perl will likely close the file descriptor
264 another time when the filehandle is destroyed. Normally, you can
265 safely call perls "close" or just let filehandles go out of scope.
266 309
267 This is supposed to be a bug in the API, so that might change. It's 310 Unfortunately, you can't do this to perl. Perl *insists* very
268 therefore best to avoid this function. 311 strongly on closing the file descriptor associated with the
312 filehandle itself.
313
314 Therefore, "aio_close" will not close the filehandle - instead it
315 will use dup2 to overwrite the file descriptor with the write-end of
316 a pipe (the pipe fd will be created on demand and will be cached).
317
318 Or in other words: the file descriptor will be closed, but it will
319 not be free for reuse until the perl filehandle is closed.
269 320
270 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 321 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
271 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 322 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
272 Reads or writes "length" bytes from the specified "fh" and "offset" 323 Reads or writes $length bytes from or to the specified $fh and
273 into the scalar given by "data" and offset "dataoffset" and calls 324 $offset into the scalar given by $data and offset $dataoffset and
274 the callback without the actual number of bytes read (or -1 on 325 calls the callback without the actual number of bytes read (or -1 on
275 error, just like the syscall). 326 error, just like the syscall).
276 327
328 "aio_read" will, like "sysread", shrink or grow the $data scalar to
329 offset plus the actual number of bytes read.
330
331 If $offset is undefined, then the current file descriptor offset
332 will be used (and updated), otherwise the file descriptor offset
333 will not be changed by these calls.
334
335 If $length is undefined in "aio_write", use the remaining length of
336 $data.
337
338 If $dataoffset is less than zero, it will be counted from the end of
339 $data.
340
277 The $data scalar *MUST NOT* be modified in any way while the request 341 The $data scalar *MUST NOT* be modified in any way while the request
278 is outstanding. Modifying it can result in segfaults or WW3 (if the 342 is outstanding. Modifying it can result in segfaults or World War
279 necessary/optional hardware is installed). 343 III (if the necessary/optional hardware is installed).
280 344
281 Example: Read 15 bytes at offset 7 into scalar $buffer, starting at 345 Example: Read 15 bytes at offset 7 into scalar $buffer, starting at
282 offset 0 within the scalar: 346 offset 0 within the scalar:
283 347
284 aio_read $fh, 7, 15, $buffer, 0, sub { 348 aio_read $fh, 7, 15, $buffer, 0, sub {
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293 more than one "aio_sendfile" per $out_fh, as they will interfere 357 more than one "aio_sendfile" per $out_fh, as they will interfere
294 with each other. 358 with each other.
295 359
296 This call tries to make use of a native "sendfile" syscall to 360 This call tries to make use of a native "sendfile" syscall to
297 provide zero-copy operation. For this to work, $out_fh should refer 361 provide zero-copy operation. For this to work, $out_fh should refer
298 to a socket, and $in_fh should refer to mmap'able file. 362 to a socket, and $in_fh should refer to an mmap'able file.
299 363
300 If the native sendfile call fails or is not implemented, it will be 364 If a native sendfile cannot be found or it fails with "ENOSYS",
365 "ENOTSUP", "EOPNOTSUPP", "EAFNOSUPPORT", "EPROTOTYPE" or "ENOTSOCK",
301 emulated, so you can call "aio_sendfile" on any type of filehandle 366 it will be emulated, so you can call "aio_sendfile" on any type of
302 regardless of the limitations of the operating system. 367 filehandle regardless of the limitations of the operating system.
303 368
304 Please note, however, that "aio_sendfile" can read more bytes from 369 Please note, however, that "aio_sendfile" can read more bytes from
305 $in_fh than are written, and there is no way to find out how many 370 $in_fh than are written, and there is no way to find out how many
306 bytes have been read from "aio_sendfile" alone, as "aio_sendfile" 371 bytes have been read from "aio_sendfile" alone, as "aio_sendfile"
307 only provides the number of bytes written to $out_fh. Only if the 372 only provides the number of bytes written to $out_fh. Only if the
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342 aio_stat "/etc/passwd", sub { 407 aio_stat "/etc/passwd", sub {
343 $_[0] and die "stat failed: $!"; 408 $_[0] and die "stat failed: $!";
344 print "size is ", -s _, "\n"; 409 print "size is ", -s _, "\n";
345 }; 410 };
346 411
412 aio_statvfs $fh_or_path, $callback->($statvfs)
413 Works like the POSIX "statvfs" or "fstatvfs" syscalls, depending on
414 whether a file handle or path was passed.
415
416 On success, the callback is passed a hash reference with the
417 following members: "bsize", "frsize", "blocks", "bfree", "bavail",
418 "files", "ffree", "favail", "fsid", "flag" and "namemax". On
419 failure, "undef" is passed.
420
421 The following POSIX IO::AIO::ST_* constants are defined: "ST_RDONLY"
422 and "ST_NOSUID".
423
424 The following non-POSIX IO::AIO::ST_* flag masks are defined to
425 their correct value when available, or to 0 on systems that do not
426 support them: "ST_NODEV", "ST_NOEXEC", "ST_SYNCHRONOUS",
427 "ST_MANDLOCK", "ST_WRITE", "ST_APPEND", "ST_IMMUTABLE",
428 "ST_NOATIME", "ST_NODIRATIME" and "ST_RELATIME".
429
430 Example: stat "/wd" and dump out the data if successful.
431
432 aio_statvfs "/wd", sub {
433 my $f = $_[0]
434 or die "statvfs: $!";
435
436 use Data::Dumper;
437 say Dumper $f;
438 };
439
440 # result:
441 {
442 bsize => 1024,
443 bfree => 4333064312,
444 blocks => 10253828096,
445 files => 2050765568,
446 flag => 4096,
447 favail => 2042092649,
448 bavail => 4333064312,
449 ffree => 2042092649,
450 namemax => 255,
451 frsize => 1024,
452 fsid => 1810
453 }
454
455 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
456 Works like perl's "utime" function (including the special case of
457 $atime and $mtime being undef). Fractional times are supported if
458 the underlying syscalls support them.
459
460 When called with a pathname, uses utimes(2) if available, otherwise
461 utime(2). If called on a file descriptor, uses futimes(2) if
462 available, otherwise returns ENOSYS, so this is not portable.
463
464 Examples:
465
466 # set atime and mtime to current time (basically touch(1)):
467 aio_utime "path", undef, undef;
468 # set atime to current time and mtime to beginning of the epoch:
469 aio_utime "path", time, undef; # undef==0
470
471 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
472 Works like perl's "chown" function, except that "undef" for either
473 $uid or $gid is being interpreted as "do not change" (but -1 can
474 also be used).
475
476 Examples:
477
478 # same as "chown root path" in the shell:
479 aio_chown "path", 0, -1;
480 # same as above:
481 aio_chown "path", 0, undef;
482
483 aio_truncate $fh_or_path, $offset, $callback->($status)
484 Works like truncate(2) or ftruncate(2).
485
486 aio_chmod $fh_or_path, $mode, $callback->($status)
487 Works like perl's "chmod" function.
488
347 aio_unlink $pathname, $callback->($status) 489 aio_unlink $pathname, $callback->($status)
348 Asynchronously unlink (delete) a file and call the callback with the 490 Asynchronously unlink (delete) a file and call the callback with the
349 result code. 491 result code.
350 492
351 aio_mknod $path, $mode, $dev, $callback->($status) 493 aio_mknod $path, $mode, $dev, $callback->($status)
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373 515
374 aio_rename $srcpath, $dstpath, $callback->($status) 516 aio_rename $srcpath, $dstpath, $callback->($status)
375 Asynchronously rename the object at $srcpath to $dstpath, just as 517 Asynchronously rename the object at $srcpath to $dstpath, just as
376 rename(2) and call the callback with the result code. 518 rename(2) and call the callback with the result code.
377 519
520 aio_mkdir $pathname, $mode, $callback->($status)
521 Asynchronously mkdir (create) a directory and call the callback with
522 the result code. $mode will be modified by the umask at the time the
523 request is executed, so do not change your umask.
524
378 aio_rmdir $pathname, $callback->($status) 525 aio_rmdir $pathname, $callback->($status)
379 Asynchronously rmdir (delete) a directory and call the callback with 526 Asynchronously rmdir (delete) a directory and call the callback with
380 the result code. 527 the result code.
381 528
382 aio_readdir $pathname, $callback->($entries) 529 aio_readdir $pathname, $callback->($entries)
383 Unlike the POSIX call of the same name, "aio_readdir" reads an 530 Unlike the POSIX call of the same name, "aio_readdir" reads an
384 entire directory (i.e. opendir + readdir + closedir). The entries 531 entire directory (i.e. opendir + readdir + closedir). The entries
385 will not be sorted, and will NOT include the "." and ".." entries. 532 will not be sorted, and will NOT include the "." and ".." entries.
386 533
387 The callback a single argument which is either "undef" or an 534 The callback is passed a single argument which is either "undef" or
388 array-ref with the filenames. 535 an array-ref with the filenames.
536
537 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
538 Quite similar to "aio_readdir", but the $flags argument allows to
539 tune behaviour and output format. In case of an error, $entries will
540 be "undef".
541
542 The flags are a combination of the following constants, ORed
543 together (the flags will also be passed to the callback, possibly
544 modified):
545
546 IO::AIO::READDIR_DENTS
547 When this flag is off, then the callback gets an arrayref with
548 of names only (as with "aio_readdir"), otherwise it gets an
549 arrayref with "[$name, $type, $inode]" arrayrefs, each
550 describing a single directory entry in more detail.
551
552 $name is the name of the entry.
553
554 $type is one of the "IO::AIO::DT_xxx" constants:
555
556 "IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR",
557 "IO::AIO::DT_DIR", "IO::AIO::DT_BLK", "IO::AIO::DT_REG",
558 "IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT".
559
560 "IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If
561 you need to know, you have to run stat yourself. Also, for speed
562 reasons, the $type scalars are read-only: you can not modify
563 them.
564
565 $inode is the inode number (which might not be exact on systems
566 with 64 bit inode numbers and 32 bit perls). This field has
567 unspecified content on systems that do not deliver the inode
568 information.
569
570 IO::AIO::READDIR_DIRS_FIRST
571 When this flag is set, then the names will be returned in an
572 order where likely directories come first. This is useful when
573 you need to quickly find directories, or you want to find all
574 directories while avoiding to stat() each entry.
575
576 If the system returns type information in readdir, then this is
577 used to find directories directly. Otherwise, likely directories
578 are files beginning with ".", or otherwise files with no dots,
579 of which files with short names are tried first.
580
581 IO::AIO::READDIR_STAT_ORDER
582 When this flag is set, then the names will be returned in an
583 order suitable for stat()'ing each one. That is, when you plan
584 to stat() all files in the given directory, then the returned
585 order will likely be fastest.
586
587 If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are
588 specified, then the likely dirs come first, resulting in a less
589 optimal stat order.
590
591 IO::AIO::READDIR_FOUND_UNKNOWN
592 This flag should not be set when calling "aio_readdirx".
593 Instead, it is being set by "aio_readdirx", when any of the
594 $type's found were "IO::AIO::DT_UNKNOWN". The absense of this
595 flag therefore indicates that all $type's are known, which can
596 be used to speed up some algorithms.
389 597
390 aio_load $path, $data, $callback->($status) 598 aio_load $path, $data, $callback->($status)
391 This is a composite request that tries to fully load the given file 599 This is a composite request that tries to fully load the given file
392 into memory. Status is the same as with aio_read. 600 into memory. Status is the same as with aio_read.
393 601
394 aio_copy $srcpath, $dstpath, $callback->($status) 602 aio_copy $srcpath, $dstpath, $callback->($status)
395 Try to copy the *file* (directories not supported as either source 603 Try to copy the *file* (directories not supported as either source
396 or destination) from $srcpath to $dstpath and call the callback with 604 or destination) from $srcpath to $dstpath and call the callback with
397 the 0 (error) or -1 ok. 605 a status of 0 (ok) or -1 (error, see $!).
398 606
399 This is a composite request that it creates the destination file 607 This is a composite request that creates the destination file with
400 with mode 0200 and copies the contents of the source file into it 608 mode 0200 and copies the contents of the source file into it using
401 using "aio_sendfile", followed by restoring atime, mtime, access 609 "aio_sendfile", followed by restoring atime, mtime, access mode and
402 mode and uid/gid, in that order. 610 uid/gid, in that order.
403 611
404 If an error occurs, the partial destination file will be unlinked, 612 If an error occurs, the partial destination file will be unlinked,
405 if possible, except when setting atime, mtime, access mode and 613 if possible, except when setting atime, mtime, access mode and
406 uid/gid, where errors are being ignored. 614 uid/gid, where errors are being ignored.
407 615
408 aio_move $srcpath, $dstpath, $callback->($status) 616 aio_move $srcpath, $dstpath, $callback->($status)
409 Try to move the *file* (directories not supported as either source 617 Try to move the *file* (directories not supported as either source
410 or destination) from $srcpath to $dstpath and call the callback with 618 or destination) from $srcpath to $dstpath and call the callback with
411 the 0 (error) or -1 ok. 619 a status of 0 (ok) or -1 (error, see $!).
412 620
413 This is a composite request that tries to rename(2) the file first. 621 This is a composite request that tries to rename(2) the file first;
414 If rename files with "EXDEV", it copies the file with "aio_copy" 622 if rename fails with "EXDEV", it copies the file with "aio_copy"
415 and, if that is successful, unlinking the $srcpath. 623 and, if that is successful, unlinks the $srcpath.
416 624
417 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 625 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
418 Scans a directory (similar to "aio_readdir") but additionally tries 626 Scans a directory (similar to "aio_readdir") but additionally tries
419 to efficiently separate the entries of directory $path into two sets 627 to efficiently separate the entries of directory $path into two sets
420 of names, directories you can recurse into (directories), and ones 628 of names, directories you can recurse into (directories), and ones
… …
440 Implementation notes. 648 Implementation notes.
441 649
442 The "aio_readdir" cannot be avoided, but "stat()"'ing every entry 650 The "aio_readdir" cannot be avoided, but "stat()"'ing every entry
443 can. 651 can.
444 652
653 If readdir returns file type information, then this is used directly
654 to find directories.
655
445 After reading the directory, the modification time, size etc. of the 656 Otherwise, after reading the directory, the modification time, size
446 directory before and after the readdir is checked, and if they match 657 etc. of the directory before and after the readdir is checked, and
447 (and isn't the current time), the link count will be used to decide 658 if they match (and isn't the current time), the link count will be
448 how many entries are directories (if >= 2). Otherwise, no knowledge 659 used to decide how many entries are directories (if >= 2).
449 of the number of subdirectories will be assumed. 660 Otherwise, no knowledge of the number of subdirectories will be
661 assumed.
450 662
451 Then entries will be sorted into likely directories (everything 663 Then entries will be sorted into likely directories a non-initial
452 without a non-initial dot currently) and likely non-directories 664 dot currently) and likely non-directories (see "aio_readdirx"). Then
453 (everything else). Then every entry plus an appended "/." will be 665 every entry plus an appended "/." will be "stat"'ed, likely
454 "stat"'ed, likely directories first. If that succeeds, it assumes 666 directories first, in order of their inode numbers. If that
455 that the entry is a directory or a symlink to directory (which will 667 succeeds, it assumes that the entry is a directory or a symlink to
456 be checked seperately). This is often faster than stat'ing the entry 668 directory (which will be checked seperately). This is often faster
457 itself because filesystems might detect the type of the entry 669 than stat'ing the entry itself because filesystems might detect the
458 without reading the inode data (e.g. ext2fs filetype feature). 670 type of the entry without reading the inode data (e.g. ext2fs
671 filetype feature), even on systems that cannot return the filetype
672 information on readdir.
459 673
460 If the known number of directories (link count - 2) has been 674 If the known number of directories (link count - 2) has been
461 reached, the rest of the entries is assumed to be non-directories. 675 reached, the rest of the entries is assumed to be non-directories.
462 676
463 This only works with certainty on POSIX (= UNIX) filesystems, which 677 This only works with certainty on POSIX (= UNIX) filesystems, which
… …
465 679
466 It will also likely work on non-POSIX filesystems with reduced 680 It will also likely work on non-POSIX filesystems with reduced
467 efficiency as those tend to return 0 or 1 as link counts, which 681 efficiency as those tend to return 0 or 1 as link counts, which
468 disables the directory counting heuristic. 682 disables the directory counting heuristic.
469 683
684 aio_rmtree $path, $callback->($status)
685 Delete a directory tree starting (and including) $path, return the
686 status of the final "rmdir" only. This is a composite request that
687 uses "aio_scandir" to recurse into and rmdir directories, and unlink
688 everything else.
689
690 aio_sync $callback->($status)
691 Asynchronously call sync and call the callback when finished.
692
470 aio_fsync $fh, $callback->($status) 693 aio_fsync $fh, $callback->($status)
471 Asynchronously call fsync on the given filehandle and call the 694 Asynchronously call fsync on the given filehandle and call the
472 callback with the fsync result code. 695 callback with the fsync result code.
473 696
474 aio_fdatasync $fh, $callback->($status) 697 aio_fdatasync $fh, $callback->($status)
475 Asynchronously call fdatasync on the given filehandle and call the 698 Asynchronously call fdatasync on the given filehandle and call the
476 callback with the fdatasync result code. 699 callback with the fdatasync result code.
477 700
478 If this call isn't available because your OS lacks it or it couldn't 701 If this call isn't available because your OS lacks it or it couldn't
479 be detected, it will be emulated by calling "fsync" instead. 702 be detected, it will be emulated by calling "fsync" instead.
703
704 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
705 Sync the data portion of the file specified by $offset and $length
706 to disk (but NOT the metadata), by calling the Linux-specific
707 sync_file_range call. If sync_file_range is not available or it
708 returns ENOSYS, then fdatasync or fsync is being substituted.
709
710 $flags can be a combination of
711 "IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE",
712 "IO::AIO::SYNC_FILE_RANGE_WRITE" and
713 "IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER": refer to the sync_file_range
714 manpage for details.
715
716 aio_pathsync $path, $callback->($status)
717 This request tries to open, fsync and close the given path. This is
718 a composite request intended to sync directories after directory
719 operations (E.g. rename). This might not work on all operating
720 systems or have any specific effect, but usually it makes sure that
721 directory changes get written to disc. It works for anything that
722 can be opened for read-only, not just directories.
723
724 Future versions of this function might fall back to other methods
725 when "fsync" on the directory fails (such as calling "sync").
726
727 Passes 0 when everything went ok, and -1 on error.
728
729 aio_msync $scalar, $offset = 0, $length = undef, flags = 0,
730 $callback->($status)
731 This is a rather advanced IO::AIO call, which only works on
732 mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it
733 also works on data scalars managed by the Sys::Mmap or Mmap modules,
734 note that the scalar must only be modified in-place while an aio
735 operation is pending on it).
736
737 It calls the "msync" function of your OS, if available, with the
738 memory area starting at $offset in the string and ending $length
739 bytes later. If $length is negative, counts from the end, and if
740 $length is "undef", then it goes till the end of the string. The
741 flags can be a combination of "IO::AIO::MS_ASYNC",
742 "IO::AIO::MS_INVALIDATE" and "IO::AIO::MS_SYNC".
743
744 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0,
745 $callback->($status)
746 This is a rather advanced IO::AIO call, which works best on
747 mmap(2)ed scalars.
748
749 It touches (reads or writes) all memory pages in the specified range
750 inside the scalar. All caveats and parameters are the same as for
751 "aio_msync", above, except for flags, which must be either 0 (which
752 reads all pages and ensures they are instantiated) or
753 "IO::AIO::MT_MODIFY", which modifies the memory page s(by reading
754 and writing an octet from it, which dirties the page).
480 755
481 aio_group $callback->(...) 756 aio_group $callback->(...)
482 This is a very special aio request: Instead of doing something, it 757 This is a very special aio request: Instead of doing something, it
483 is a container for other aio requests, which is useful if you want 758 is a container for other aio requests, which is useful if you want
484 to bundle many requests into a single, composite, request with a 759 to bundle many requests into a single, composite, request with a
… …
527 802
528 cancel $req 803 cancel $req
529 Cancels the request, if possible. Has the effect of skipping 804 Cancels the request, if possible. Has the effect of skipping
530 execution when entering the execute state and skipping calling the 805 execution when entering the execute state and skipping calling the
531 callback when entering the the result state, but will leave the 806 callback when entering the the result state, but will leave the
532 request otherwise untouched. That means that requests that currently 807 request otherwise untouched (with the exception of readdir). That
533 execute will not be stopped and resources held by the request will 808 means that requests that currently execute will not be stopped and
534 not be freed prematurely. 809 resources held by the request will not be freed prematurely.
535 810
536 cb $req $callback->(...) 811 cb $req $callback->(...)
537 Replace (or simply set) the callback registered to the request. 812 Replace (or simply set) the callback registered to the request.
538 813
539 IO::AIO::GRP CLASS 814 IO::AIO::GRP CLASS
… …
566 }; 841 };
567 842
568 This makes it very easy to create composite requests (see the source of 843 This makes it very easy to create composite requests (see the source of
569 "aio_move" for an application) that work and feel like simple requests. 844 "aio_move" for an application) that work and feel like simple requests.
570 845
571 * The IO::AIO::GRP objects will be cleaned up during calls to 846 * The IO::AIO::GRP objects will be cleaned up during calls to
572 "IO::AIO::poll_cb", just like any other request. 847 "IO::AIO::poll_cb", just like any other request.
848
573 * They can be canceled like any other request. Canceling will cancel not 849 * They can be canceled like any other request. Canceling will cancel
574 only the request itself, but also all requests it contains. 850 not only the request itself, but also all requests it contains.
851
575 * They can also can also be added to other IO::AIO::GRP objects. 852 * They can also can also be added to other IO::AIO::GRP objects.
853
576 * You must not add requests to a group from within the group callback 854 * You must not add requests to a group from within the group callback
577 (or any later time). 855 (or any later time).
578 856
579 Their lifetime, simplified, looks like this: when they are empty, they 857 Their lifetime, simplified, looks like this: when they are empty, they
580 will finish very quickly. If they contain only requests that are in the 858 will finish very quickly. If they contain only requests that are in the
581 "done" state, they will also finish. Otherwise they will continue to 859 "done" state, they will also finish. Otherwise they will continue to
582 exist. 860 exist.
583 861
584 That means after creating a group you have some time to add requests. 862 That means after creating a group you have some time to add requests
585 And in the callbacks of those requests, you can add further requests to 863 (precisely before the callback has been invoked, which is only done
586 the group. And only when all those requests have finished will the the 864 within the "poll_cb"). And in the callbacks of those requests, you can
587 group itself finish. 865 add further requests to the group. And only when all those requests have
866 finished will the the group itself finish.
588 867
589 add $grp ... 868 add $grp ...
590 $grp->add (...) 869 $grp->add (...)
591 Add one or more requests to the group. Any type of IO::AIO::REQ can 870 Add one or more requests to the group. Any type of IO::AIO::REQ can
592 be added, including other groups, as long as you do not create 871 be added, including other groups, as long as you do not create
… …
597 $grp->cancel_subs 876 $grp->cancel_subs
598 Cancel all subrequests and clears any feeder, but not the group 877 Cancel all subrequests and clears any feeder, but not the group
599 request itself. Useful when you queued a lot of events but got a 878 request itself. Useful when you queued a lot of events but got a
600 result early. 879 result early.
601 880
881 The group request will finish normally (you cannot add requests to
882 the group).
883
602 $grp->result (...) 884 $grp->result (...)
603 Set the result value(s) that will be passed to the group callback 885 Set the result value(s) that will be passed to the group callback
604 when all subrequests have finished and set thre groups errno to the 886 when all subrequests have finished and set the groups errno to the
605 current value of errno (just like calling "errno" without an error 887 current value of errno (just like calling "errno" without an error
606 number). By default, no argument will be passed and errno is zero. 888 number). By default, no argument will be passed and errno is zero.
607 889
608 $grp->errno ([$errno]) 890 $grp->errno ([$errno])
609 Sets the group errno value to $errno, or the current value of errno 891 Sets the group errno value to $errno, or the current value of errno
… …
635 does not impose any limits). 917 does not impose any limits).
636 918
637 If the feed does not queue more requests when called, it will be 919 If the feed does not queue more requests when called, it will be
638 automatically removed from the group. 920 automatically removed from the group.
639 921
640 If the feed limit is 0, it will be set to 2 automatically. 922 If the feed limit is 0 when this method is called, it will be set to
923 2 automatically.
641 924
642 Example: 925 Example:
643 926
644 # stat all files in @files, but only ever use four aio requests concurrently: 927 # stat all files in @files, but only ever use four aio requests concurrently:
645 928
… …
656 Sets the feeder limit for the group: The feeder will be called 939 Sets the feeder limit for the group: The feeder will be called
657 whenever the group contains less than this many requests. 940 whenever the group contains less than this many requests.
658 941
659 Setting the limit to 0 will pause the feeding process. 942 Setting the limit to 0 will pause the feeding process.
660 943
944 The default value for the limit is 0, but note that setting a feeder
945 automatically bumps it up to 2.
946
661 SUPPORT FUNCTIONS 947 SUPPORT FUNCTIONS
662 EVENT PROCESSING AND EVENT LOOP INTEGRATION 948 EVENT PROCESSING AND EVENT LOOP INTEGRATION
663 $fileno = IO::AIO::poll_fileno 949 $fileno = IO::AIO::poll_fileno
664 Return the *request result pipe file descriptor*. This filehandle 950 Return the *request result pipe file descriptor*. This filehandle
665 must be polled for reading by some mechanism outside this module 951 must be polled for reading by some mechanism outside this module
666 (e.g. Event or select, see below or the SYNOPSIS). If the pipe 952 (e.g. EV, Glib, select and so on, see below or the SYNOPSIS). If the
667 becomes readable you have to call "poll_cb" to check the results. 953 pipe becomes readable you have to call "poll_cb" to check the
954 results.
668 955
669 See "poll_cb" for an example. 956 See "poll_cb" for an example.
670 957
671 IO::AIO::poll_cb 958 IO::AIO::poll_cb
672 Process some outstanding events on the result pipe. You have to call 959 Process some outstanding events on the result pipe. You have to call
673 this regularly. Returns the number of events processed. Returns 960 this regularly. Returns 0 if all events could be processed, or -1 if
674 immediately when no events are outstanding. The amount of events 961 it returned earlier for whatever reason. Returns immediately when no
962 events are outstanding. The amount of events processed depends on
675 processed depends on the settings of "IO::AIO::max_poll_req" and 963 the settings of "IO::AIO::max_poll_req" and
676 "IO::AIO::max_poll_time". 964 "IO::AIO::max_poll_time".
677 965
678 If not all requests were processed for whatever reason, the 966 If not all requests were processed for whatever reason, the
679 filehandle will still be ready when "poll_cb" returns. 967 filehandle will still be ready when "poll_cb" returns, so normally
968 you don't have to do anything special to have it called later.
680 969
681 Example: Install an Event watcher that automatically calls 970 Example: Install an Event watcher that automatically calls
682 IO::AIO::poll_cb with high priority: 971 IO::AIO::poll_cb with high priority (more examples can be found in
972 the SYNOPSIS section, at the top of this document):
683 973
684 Event->io (fd => IO::AIO::poll_fileno, 974 Event->io (fd => IO::AIO::poll_fileno,
685 poll => 'r', async => 1, 975 poll => 'r', async => 1,
686 cb => \&IO::AIO::poll_cb); 976 cb => \&IO::AIO::poll_cb);
977
978 IO::AIO::poll_wait
979 If there are any outstanding requests and none of them in the result
980 phase, wait till the result filehandle becomes ready for reading
981 (simply does a "select" on the filehandle. This is useful if you
982 want to synchronously wait for some requests to finish).
983
984 See "nreqs" for an example.
985
986 IO::AIO::poll
987 Waits until some requests have been handled.
988
989 Returns the number of requests processed, but is otherwise strictly
990 equivalent to:
991
992 IO::AIO::poll_wait, IO::AIO::poll_cb
993
994 IO::AIO::flush
995 Wait till all outstanding AIO requests have been handled.
996
997 Strictly equivalent to:
998
999 IO::AIO::poll_wait, IO::AIO::poll_cb
1000 while IO::AIO::nreqs;
687 1001
688 IO::AIO::max_poll_reqs $nreqs 1002 IO::AIO::max_poll_reqs $nreqs
689 IO::AIO::max_poll_time $seconds 1003 IO::AIO::max_poll_time $seconds
690 These set the maximum number of requests (default 0, meaning 1004 These set the maximum number of requests (default 0, meaning
691 infinity) that are being processed by "IO::AIO::poll_cb" in one 1005 infinity) that are being processed by "IO::AIO::poll_cb" in one
… …
715 # use a low priority so other tasks have priority 1029 # use a low priority so other tasks have priority
716 Event->io (fd => IO::AIO::poll_fileno, 1030 Event->io (fd => IO::AIO::poll_fileno,
717 poll => 'r', nice => 1, 1031 poll => 'r', nice => 1,
718 cb => &IO::AIO::poll_cb); 1032 cb => &IO::AIO::poll_cb);
719 1033
720 IO::AIO::poll_wait
721 If there are any outstanding requests and none of them in the result
722 phase, wait till the result filehandle becomes ready for reading
723 (simply does a "select" on the filehandle. This is useful if you
724 want to synchronously wait for some requests to finish).
725
726 See "nreqs" for an example.
727
728 IO::AIO::poll
729 Waits until some requests have been handled.
730
731 Returns the number of requests processed, but is otherwise strictly
732 equivalent to:
733
734 IO::AIO::poll_wait, IO::AIO::poll_cb
735
736 IO::AIO::flush
737 Wait till all outstanding AIO requests have been handled.
738
739 Strictly equivalent to:
740
741 IO::AIO::poll_wait, IO::AIO::poll_cb
742 while IO::AIO::nreqs;
743
744 CONTROLLING THE NUMBER OF THREADS 1034 CONTROLLING THE NUMBER OF THREADS
745 IO::AIO::min_parallel $nthreads 1035 IO::AIO::min_parallel $nthreads
746 Set the minimum number of AIO threads to $nthreads. The current 1036 Set the minimum number of AIO threads to $nthreads. The current
747 default is 8, which means eight asynchronous operations can execute 1037 default is 8, which means eight asynchronous operations can execute
748 concurrently at any one time (the number of outstanding requests, 1038 concurrently at any one time (the number of outstanding requests,
… …
790 1080
791 The default is probably ok in most situations, especially if thread 1081 The default is probably ok in most situations, especially if thread
792 creation is fast. If thread creation is very slow on your system you 1082 creation is fast. If thread creation is very slow on your system you
793 might want to use larger values. 1083 might want to use larger values.
794 1084
795 $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1085 IO::AIO::max_outstanding $maxreqs
796 This is a very bad function to use in interactive programs because 1086 This is a very bad function to use in interactive programs because
797 it blocks, and a bad way to reduce concurrency because it is 1087 it blocks, and a bad way to reduce concurrency because it is
798 inexact: Better use an "aio_group" together with a feed callback. 1088 inexact: Better use an "aio_group" together with a feed callback.
799 1089
800 Sets the maximum number of outstanding requests to $nreqs. If you to 1090 Sets the maximum number of outstanding requests to $nreqs. If you do
801 queue up more than this number of requests, the next call to the 1091 queue up more than this number of requests, the next call to the
802 "poll_cb" (and "poll_some" and other functions calling "poll_cb") 1092 "poll_cb" (and "poll_some" and other functions calling "poll_cb")
803 function will block until the limit is no longer exceeded. 1093 function will block until the limit is no longer exceeded.
804 1094
805 The default value is very large, so there is no practical limit on 1095 The default value is very large, so there is no practical limit on
806 the number of outstanding requests. 1096 the number of outstanding requests.
807 1097
808 You can still queue as many requests as you want. Therefore, 1098 You can still queue as many requests as you want. Therefore,
809 "max_oustsanding" is mainly useful in simple scripts (with low 1099 "max_outstanding" is mainly useful in simple scripts (with low
810 values) or as a stop gap to shield against fatal memory overflow 1100 values) or as a stop gap to shield against fatal memory overflow
811 (with large values). 1101 (with large values).
812 1102
813 STATISTICAL INFORMATION 1103 STATISTICAL INFORMATION
814 IO::AIO::nreqs 1104 IO::AIO::nreqs
… …
826 executed). 1116 executed).
827 1117
828 IO::AIO::npending 1118 IO::AIO::npending
829 Returns the number of requests currently in the pending state 1119 Returns the number of requests currently in the pending state
830 (executed, but not yet processed by poll_cb). 1120 (executed, but not yet processed by poll_cb).
1121
1122 MISCELLANEOUS FUNCTIONS
1123 IO::AIO implements some functions that might be useful, but are not
1124 asynchronous.
1125
1126 IO::AIO::sendfile $ofh, $ifh, $offset, $count
1127 Calls the "eio_sendfile_sync" function, which is like
1128 "aio_sendfile", but is blocking (this makes most sense if you know
1129 the input data is likely cached already and the output filehandle is
1130 set to non-blocking operations).
1131
1132 Returns the number of bytes copied, or -1 on error.
1133
1134 IO::AIO::fadvise $fh, $offset, $len, $advice
1135 Simply calls the "posix_fadvise" function (see it's manpage for
1136 details). The following advice constants are avaiable:
1137 "IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL",
1138 "IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE",
1139 "IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED".
1140
1141 On systems that do not implement "posix_fadvise", this function
1142 returns ENOSYS, otherwise the return value of "posix_fadvise".
1143
1144 IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1145 Memory-maps a file (or anonymous memory range) and attaches it to
1146 the given $scalar, which will act like a string scalar.
1147
1148 The only operations allowed on the scalar are "substr"/"vec" that
1149 don't change the string length, and most read-only operations such
1150 as copying it or searching it with regexes and so on.
1151
1152 Anything else is unsafe and will, at best, result in memory leaks.
1153
1154 The memory map associated with the $scalar is automatically removed
1155 when the $scalar is destroyed, or when the "IO::AIO::mmap" or
1156 "IO::AIO::munmap" functions are called.
1157
1158 This calls the "mmap"(2) function internally. See your system's
1159 manual page for details on the $length, $prot and $flags parameters.
1160
1161 The $length must be larger than zero and smaller than the actual
1162 filesize.
1163
1164 $prot is a combination of "IO::AIO::PROT_NONE",
1165 "IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or
1166 "IO::AIO::PROT_WRITE",
1167
1168 $flags can be a combination of "IO::AIO::MAP_SHARED" or
1169 "IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when
1170 not available, the are defined as 0): "IO::AIO::MAP_ANONYMOUS"
1171 (which is set to "MAP_ANON" if your system only provides this
1172 constant), "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED",
1173 "IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE" or
1174 "IO::AIO::MAP_NONBLOCK"
1175
1176 If $fh is "undef", then a file descriptor of -1 is passed.
1177
1178 $offset is the offset from the start of the file - it generally must
1179 be a multiple of "IO::AIO::PAGESIZE" and defaults to 0.
1180
1181 Example:
1182
1183 use Digest::MD5;
1184 use IO::AIO;
1185
1186 open my $fh, "<verybigfile"
1187 or die "$!";
1188
1189 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1190 or die "verybigfile: $!";
1191
1192 my $fast_md5 = md5 $data;
1193
1194 IO::AIO::munmap $scalar
1195 Removes a previous mmap and undefines the $scalar.
1196
1197 IO::AIO::mlockall $flags
1198 Calls the "mlockall" function with the given $flags (a combination
1199 of "IO::AIO::MCL_CURRENT" and "IO::AIO::MCL__FUTURE").
1200
1201 On systems that do not implement "mlockall", this function returns
1202 ENOSYS, otherwise the return value of "mlockall".
1203
1204 IO::AIO::munlockall
1205 Calls the "munlockall" function.
1206
1207 On systems that do not implement "munlockall", this function returns
1208 ENOSYS, otherwise the return value of "munlockall".
1209
1210EVENT LOOP INTEGRATION
1211 It is recommended to use AnyEvent::AIO to integrate IO::AIO
1212 automatically into many event loops:
1213
1214 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1215 use AnyEvent::AIO;
1216
1217 You can also integrate IO::AIO manually into many event loops, here are
1218 some examples of how to do this:
1219
1220 # EV integration
1221 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1222
1223 # Event integration
1224 Event->io (fd => IO::AIO::poll_fileno,
1225 poll => 'r',
1226 cb => \&IO::AIO::poll_cb);
1227
1228 # Glib/Gtk2 integration
1229 add_watch Glib::IO IO::AIO::poll_fileno,
1230 in => sub { IO::AIO::poll_cb; 1 };
1231
1232 # Tk integration
1233 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1234 readable => \&IO::AIO::poll_cb);
1235
1236 # Danga::Socket integration
1237 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1238 \&IO::AIO::poll_cb);
831 1239
832 FORK BEHAVIOUR 1240 FORK BEHAVIOUR
833 This module should do "the right thing" when the process using it forks: 1241 This module should do "the right thing" when the process using it forks:
834 1242
835 Before the fork, IO::AIO enters a quiescent state where no requests can 1243 Before the fork, IO::AIO enters a quiescent state where no requests can
… …
851 bytes of memory. In addition, stat requests need a stat buffer (possibly 1259 bytes of memory. In addition, stat requests need a stat buffer (possibly
852 a few hundred bytes), readdir requires a result buffer and so on. Perl 1260 a few hundred bytes), readdir requires a result buffer and so on. Perl
853 scalars and other data passed into aio requests will also be locked and 1261 scalars and other data passed into aio requests will also be locked and
854 will consume memory till the request has entered the done state. 1262 will consume memory till the request has entered the done state.
855 1263
856 This is now awfully much, so queuing lots of requests is not usually a 1264 This is not awfully much, so queuing lots of requests is not usually a
857 problem. 1265 problem.
858 1266
859 Per-thread usage: 1267 Per-thread usage:
860 1268
861 In the execution phase, some aio requests require more memory for 1269 In the execution phase, some aio requests require more memory for
… …
864 1272
865KNOWN BUGS 1273KNOWN BUGS
866 Known bugs will be fixed in the next release. 1274 Known bugs will be fixed in the next release.
867 1275
868SEE ALSO 1276SEE ALSO
869 Coro::AIO. 1277 AnyEvent::AIO for easy integration into event loops, Coro::AIO for a
1278 more natural syntax.
870 1279
871AUTHOR 1280AUTHOR
872 Marc Lehmann <schmorp@schmorp.de> 1281 Marc Lehmann <schmorp@schmorp.de>
873 http://home.schmorp.de/ 1282 http://home.schmorp.de/
874 1283

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