… | |
… | |
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 |
29 | # AnyEvent integration (EV, Event, Glib, Tk, urxvt, pureperl...) |
30 | open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; |
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 }); |
31 | my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb }); |
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32 | |
|
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33 | # EV integration |
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34 | my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
32 | |
35 | |
33 | # Event integration |
36 | # Event integration |
34 | Event->io (fd => IO::AIO::poll_fileno, |
37 | Event->io (fd => IO::AIO::poll_fileno, |
35 | poll => 'r', |
38 | poll => 'r', |
36 | cb => \&IO::AIO::poll_cb); |
39 | cb => \&IO::AIO::poll_cb); |
… | |
… | |
61 | faster on a RAID volume or over NFS when you do a number of stat |
64 | faster on a RAID volume or over NFS when you do a number of stat |
62 | operations concurrently. |
65 | operations concurrently. |
63 | |
66 | |
64 | While most of this works on all types of file descriptors (for example |
67 | While most of this works on all types of file descriptors (for example |
65 | sockets), using these functions on file descriptors that support |
68 | sockets), using these functions on file descriptors that support |
66 | nonblocking operation (again, sockets, pipes etc.) is very inefficient |
69 | nonblocking operation (again, sockets, pipes etc.) is very inefficient. |
67 | or might not work (aio_read fails on sockets/pipes/fifos). Use an event |
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68 | loop for that (such as the Event module): IO::AIO will naturally fit |
70 | Use an event loop for that (such as the Event module): IO::AIO will |
69 | into such an event loop itself. |
71 | naturally fit into such an event loop itself. |
70 | |
72 | |
71 | In this version, a number of threads are started that execute your |
73 | 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 |
74 | 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 |
75 | 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 |
76 | perl. In the future, this module might make use of the native aio |
… | |
… | |
76 | not well-supported or restricted (GNU/Linux doesn't allow them on normal |
78 | 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 |
79 | files currently, for example), and they would only support aio_read and |
78 | aio_write, so the remaining functionality would have to be implemented |
80 | aio_write, so the remaining functionality would have to be implemented |
79 | using threads anyway. |
81 | using threads anyway. |
80 | |
82 | |
81 | Although the module will work with in the presence of other (Perl-) |
83 | 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 |
84 | 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 |
85 | yourself, always call "poll_cb" from within the same thread, or never |
84 | never call "poll_cb" (or other "aio_" functions) recursively. |
86 | call "poll_cb" (or other "aio_" functions) recursively. |
85 | |
87 | |
86 | EXAMPLE |
88 | EXAMPLE |
87 | This is a simple example that uses the Event module and loads |
89 | This is a simple example that uses the Event module and loads |
88 | /etc/passwd asynchronously: |
90 | /etc/passwd asynchronously: |
89 | |
91 | |
… | |
… | |
259 | } |
261 | } |
260 | }; |
262 | }; |
261 | |
263 | |
262 | aio_close $fh, $callback->($status) |
264 | aio_close $fh, $callback->($status) |
263 | Asynchronously close a file and call the callback with the result |
265 | Asynchronously close a file and call the callback with the result |
264 | code. *WARNING:* although accepted, you should not pass in a perl |
266 | code. |
265 | filehandle here, as perl will likely close the file descriptor |
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266 | another time when the filehandle is destroyed. Normally, you can |
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267 | safely call perls "close" or just let filehandles go out of scope. |
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268 | |
267 | |
269 | This is supposed to be a bug in the API, so that might change. It's |
268 | Unfortunately, you can't do this to perl. Perl *insists* very |
270 | therefore best to avoid this function. |
269 | strongly on closing the file descriptor associated with the |
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270 | filehandle itself. Here is what aio_close will try: |
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271 | |
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272 | 1. dup()licate the fd |
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273 | 2. asynchronously close() the duplicated fd |
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274 | 3. dup()licate the fd once more |
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275 | 4. let perl close() the filehandle |
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276 | 5. asynchronously close the duplicated fd |
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277 | |
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278 | The idea is that the first close() flushes stuff to disk that |
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279 | closing an fd will flush, so when perl closes the fd, nothing much |
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280 | will need to be flushed. The second async. close() will then flush |
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281 | stuff to disk that closing the last fd to the file will flush. |
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282 | |
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283 | Just FYI, SuSv3 has this to say on close: |
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284 | |
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285 | All outstanding record locks owned by the process on the file |
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286 | associated with the file descriptor shall be removed. |
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287 | |
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288 | If fildes refers to a socket, close() shall cause the socket to be |
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289 | destroyed. ... close() shall block for up to the current linger |
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290 | interval until all data is transmitted. |
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291 | [this actually sounds like a specification bug, but who knows] |
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292 | |
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293 | And at least Linux additionally actually flushes stuff on every |
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294 | close, even when the file itself is still open. |
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295 | |
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296 | Sounds enourmously inefficient and complicated? Yes... please show |
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297 | me how to nuke perl's fd out of existence... |
271 | |
298 | |
272 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
299 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
273 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
300 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
274 | Reads or writes "length" bytes from the specified "fh" and "offset" |
301 | Reads or writes $length bytes from the specified $fh and $offset |
275 | into the scalar given by "data" and offset "dataoffset" and calls |
302 | into the scalar given by $data and offset $dataoffset and calls the |
276 | the callback without the actual number of bytes read (or -1 on |
303 | callback without the actual number of bytes read (or -1 on error, |
277 | error, just like the syscall). |
304 | just like the syscall). |
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305 | |
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306 | If $offset is undefined, then the current file descriptor offset |
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307 | will be used (and updated), otherwise the file descriptor offset |
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308 | will not be changed by these calls. |
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309 | |
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310 | If $length is undefined in "aio_write", use the remaining length of |
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311 | $data. |
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312 | |
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313 | If $dataoffset is less than zero, it will be counted from the end of |
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314 | $data. |
278 | |
315 | |
279 | The $data scalar *MUST NOT* be modified in any way while the request |
316 | The $data scalar *MUST NOT* be modified in any way while the request |
280 | is outstanding. Modifying it can result in segfaults or WW3 (if the |
317 | is outstanding. Modifying it can result in segfaults or World War |
281 | necessary/optional hardware is installed). |
318 | III (if the necessary/optional hardware is installed). |
282 | |
319 | |
283 | Example: Read 15 bytes at offset 7 into scalar $buffer, starting at |
320 | Example: Read 15 bytes at offset 7 into scalar $buffer, starting at |
284 | offset 0 within the scalar: |
321 | offset 0 within the scalar: |
285 | |
322 | |
286 | aio_read $fh, 7, 15, $buffer, 0, sub { |
323 | aio_read $fh, 7, 15, $buffer, 0, sub { |
… | |
… | |
344 | aio_stat "/etc/passwd", sub { |
381 | aio_stat "/etc/passwd", sub { |
345 | $_[0] and die "stat failed: $!"; |
382 | $_[0] and die "stat failed: $!"; |
346 | print "size is ", -s _, "\n"; |
383 | print "size is ", -s _, "\n"; |
347 | }; |
384 | }; |
348 | |
385 | |
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386 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
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387 | Works like perl's "utime" function (including the special case of |
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388 | $atime and $mtime being undef). Fractional times are supported if |
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389 | the underlying syscalls support them. |
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390 | |
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391 | When called with a pathname, uses utimes(2) if available, otherwise |
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392 | utime(2). If called on a file descriptor, uses futimes(2) if |
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393 | available, otherwise returns ENOSYS, so this is not portable. |
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394 | |
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395 | Examples: |
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396 | |
|
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397 | # set atime and mtime to current time (basically touch(1)): |
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398 | aio_utime "path", undef, undef; |
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399 | # set atime to current time and mtime to beginning of the epoch: |
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400 | aio_utime "path", time, undef; # undef==0 |
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401 | |
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402 | aio_chown $fh_or_path, $uid, $gid, $callback->($status) |
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403 | Works like perl's "chown" function, except that "undef" for either |
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404 | $uid or $gid is being interpreted as "do not change" (but -1 can |
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405 | also be used). |
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406 | |
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407 | Examples: |
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408 | |
|
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409 | # same as "chown root path" in the shell: |
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410 | aio_chown "path", 0, -1; |
|
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411 | # same as above: |
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412 | aio_chown "path", 0, undef; |
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413 | |
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414 | aio_truncate $fh_or_path, $offset, $callback->($status) |
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415 | Works like truncate(2) or ftruncate(2). |
|
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416 | |
|
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417 | aio_chmod $fh_or_path, $mode, $callback->($status) |
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418 | Works like perl's "chmod" function. |
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|
419 | |
349 | aio_unlink $pathname, $callback->($status) |
420 | aio_unlink $pathname, $callback->($status) |
350 | Asynchronously unlink (delete) a file and call the callback with the |
421 | Asynchronously unlink (delete) a file and call the callback with the |
351 | result code. |
422 | result code. |
352 | |
423 | |
353 | aio_mknod $path, $mode, $dev, $callback->($status) |
424 | aio_mknod $path, $mode, $dev, $callback->($status) |
… | |
… | |
478 | Delete a directory tree starting (and including) $path, return the |
549 | Delete a directory tree starting (and including) $path, return the |
479 | status of the final "rmdir" only. This is a composite request that |
550 | status of the final "rmdir" only. This is a composite request that |
480 | uses "aio_scandir" to recurse into and rmdir directories, and unlink |
551 | uses "aio_scandir" to recurse into and rmdir directories, and unlink |
481 | everything else. |
552 | everything else. |
482 | |
553 | |
|
|
554 | aio_sync $callback->($status) |
|
|
555 | Asynchronously call sync and call the callback when finished. |
|
|
556 | |
483 | aio_fsync $fh, $callback->($status) |
557 | aio_fsync $fh, $callback->($status) |
484 | Asynchronously call fsync on the given filehandle and call the |
558 | Asynchronously call fsync on the given filehandle and call the |
485 | callback with the fsync result code. |
559 | callback with the fsync result code. |
486 | |
560 | |
487 | aio_fdatasync $fh, $callback->($status) |
561 | aio_fdatasync $fh, $callback->($status) |
488 | Asynchronously call fdatasync on the given filehandle and call the |
562 | Asynchronously call fdatasync on the given filehandle and call the |
489 | callback with the fdatasync result code. |
563 | callback with the fdatasync result code. |
490 | |
564 | |
491 | If this call isn't available because your OS lacks it or it couldn't |
565 | If this call isn't available because your OS lacks it or it couldn't |
492 | be detected, it will be emulated by calling "fsync" instead. |
566 | be detected, it will be emulated by calling "fsync" instead. |
|
|
567 | |
|
|
568 | aio_pathsync $path, $callback->($status) |
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569 | This request tries to open, fsync and close the given path. This is |
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|
570 | a composite request intended tosync directories after directory |
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571 | operations (E.g. rename). This might not work on all operating |
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572 | systems or have any specific effect, but usually it makes sure that |
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573 | directory changes get written to disc. It works for anything that |
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574 | can be opened for read-only, not just directories. |
|
|
575 | |
|
|
576 | Passes 0 when everything went ok, and -1 on error. |
493 | |
577 | |
494 | aio_group $callback->(...) |
578 | aio_group $callback->(...) |
495 | This is a very special aio request: Instead of doing something, it |
579 | This is a very special aio request: Instead of doing something, it |
496 | is a container for other aio requests, which is useful if you want |
580 | is a container for other aio requests, which is useful if you want |
497 | to bundle many requests into a single, composite, request with a |
581 | to bundle many requests into a single, composite, request with a |
… | |
… | |
579 | }; |
663 | }; |
580 | |
664 | |
581 | This makes it very easy to create composite requests (see the source of |
665 | This makes it very easy to create composite requests (see the source of |
582 | "aio_move" for an application) that work and feel like simple requests. |
666 | "aio_move" for an application) that work and feel like simple requests. |
583 | |
667 | |
584 | * The IO::AIO::GRP objects will be cleaned up during calls to |
668 | * The IO::AIO::GRP objects will be cleaned up during calls to |
585 | "IO::AIO::poll_cb", just like any other request. |
669 | "IO::AIO::poll_cb", just like any other request. |
|
|
670 | |
586 | * They can be canceled like any other request. Canceling will cancel not |
671 | * They can be canceled like any other request. Canceling will cancel |
587 | only the request itself, but also all requests it contains. |
672 | not only the request itself, but also all requests it contains. |
|
|
673 | |
588 | * They can also can also be added to other IO::AIO::GRP objects. |
674 | * They can also can also be added to other IO::AIO::GRP objects. |
|
|
675 | |
589 | * You must not add requests to a group from within the group callback |
676 | * You must not add requests to a group from within the group callback |
590 | (or any later time). |
677 | (or any later time). |
591 | |
678 | |
592 | Their lifetime, simplified, looks like this: when they are empty, they |
679 | Their lifetime, simplified, looks like this: when they are empty, they |
593 | will finish very quickly. If they contain only requests that are in the |
680 | will finish very quickly. If they contain only requests that are in the |
594 | "done" state, they will also finish. Otherwise they will continue to |
681 | "done" state, they will also finish. Otherwise they will continue to |
595 | exist. |
682 | exist. |
… | |
… | |
612 | request itself. Useful when you queued a lot of events but got a |
699 | request itself. Useful when you queued a lot of events but got a |
613 | result early. |
700 | result early. |
614 | |
701 | |
615 | $grp->result (...) |
702 | $grp->result (...) |
616 | Set the result value(s) that will be passed to the group callback |
703 | Set the result value(s) that will be passed to the group callback |
617 | when all subrequests have finished and set thre groups errno to the |
704 | when all subrequests have finished and set the groups errno to the |
618 | current value of errno (just like calling "errno" without an error |
705 | current value of errno (just like calling "errno" without an error |
619 | number). By default, no argument will be passed and errno is zero. |
706 | number). By default, no argument will be passed and errno is zero. |
620 | |
707 | |
621 | $grp->errno ([$errno]) |
708 | $grp->errno ([$errno]) |
622 | Sets the group errno value to $errno, or the current value of errno |
709 | Sets the group errno value to $errno, or the current value of errno |
… | |
… | |
808 | $oldmaxreqs = IO::AIO::max_outstanding $maxreqs |
895 | $oldmaxreqs = IO::AIO::max_outstanding $maxreqs |
809 | This is a very bad function to use in interactive programs because |
896 | This is a very bad function to use in interactive programs because |
810 | it blocks, and a bad way to reduce concurrency because it is |
897 | it blocks, and a bad way to reduce concurrency because it is |
811 | inexact: Better use an "aio_group" together with a feed callback. |
898 | inexact: Better use an "aio_group" together with a feed callback. |
812 | |
899 | |
813 | Sets the maximum number of outstanding requests to $nreqs. If you to |
900 | Sets the maximum number of outstanding requests to $nreqs. If you do |
814 | queue up more than this number of requests, the next call to the |
901 | queue up more than this number of requests, the next call to the |
815 | "poll_cb" (and "poll_some" and other functions calling "poll_cb") |
902 | "poll_cb" (and "poll_some" and other functions calling "poll_cb") |
816 | function will block until the limit is no longer exceeded. |
903 | function will block until the limit is no longer exceeded. |
817 | |
904 | |
818 | The default value is very large, so there is no practical limit on |
905 | The default value is very large, so there is no practical limit on |
… | |
… | |
864 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
951 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
865 | a few hundred bytes), readdir requires a result buffer and so on. Perl |
952 | a few hundred bytes), readdir requires a result buffer and so on. Perl |
866 | scalars and other data passed into aio requests will also be locked and |
953 | scalars and other data passed into aio requests will also be locked and |
867 | will consume memory till the request has entered the done state. |
954 | will consume memory till the request has entered the done state. |
868 | |
955 | |
869 | This is now awfully much, so queuing lots of requests is not usually a |
956 | This is not awfully much, so queuing lots of requests is not usually a |
870 | problem. |
957 | problem. |
871 | |
958 | |
872 | Per-thread usage: |
959 | Per-thread usage: |
873 | |
960 | |
874 | In the execution phase, some aio requests require more memory for |
961 | In the execution phase, some aio requests require more memory for |