… | |
… | |
352 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
352 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
353 | separate the entries of directory C<$path> into two sets of names, ones |
353 | separate the entries of directory C<$path> into two sets of names, ones |
354 | you can recurse into (directories or links to them), and ones you cannot |
354 | you can recurse into (directories or links to them), and ones you cannot |
355 | recurse into (everything else). |
355 | recurse into (everything else). |
356 | |
356 | |
357 | C<aio_scandir> is a composite request that consists of many sub |
357 | C<aio_scandir> is a composite request that creates of many sub requests_ |
358 | requests. C<$maxreq> specifies the maximum number of outstanding aio |
358 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
359 | requests that this function generates. If it is C<< <= 0 >>, then a |
359 | this function generates. If it is C<< <= 0 >>, then a suitable default |
360 | suitable default will be chosen (currently 8). |
360 | will be chosen (currently 6). |
361 | |
361 | |
362 | On error, the callback is called without arguments, otherwise it receives |
362 | On error, the callback is called without arguments, otherwise it receives |
363 | two array-refs with path-relative entry names. |
363 | two array-refs with path-relative entry names. |
364 | |
364 | |
365 | Example: |
365 | Example: |
… | |
… | |
404 | sub aio_scandir($$$) { |
404 | sub aio_scandir($$$) { |
405 | my ($path, $maxreq, $cb) = @_; |
405 | my ($path, $maxreq, $cb) = @_; |
406 | |
406 | |
407 | my $grp = aio_group $cb; |
407 | my $grp = aio_group $cb; |
408 | |
408 | |
409 | $maxreq = 8 if $maxreq <= 0; |
409 | $maxreq = 6 if $maxreq <= 0; |
410 | |
410 | |
411 | # stat once |
411 | # stat once |
412 | add $grp aio_stat $path, sub { |
412 | add $grp aio_stat $path, sub { |
413 | return $grp->result () if $_[0]; |
413 | return $grp->result () if $_[0]; |
414 | my $now = time; |
414 | my $now = time; |
… | |
… | |
752 | IO::AIO::poll_wait, IO::AIO::poll_cb |
752 | IO::AIO::poll_wait, IO::AIO::poll_cb |
753 | if IO::AIO::nreqs; |
753 | if IO::AIO::nreqs; |
754 | |
754 | |
755 | =item IO::AIO::min_parallel $nthreads |
755 | =item IO::AIO::min_parallel $nthreads |
756 | |
756 | |
757 | Set the minimum number of AIO threads to C<$nthreads>. The current default |
757 | Set the minimum number of AIO threads to C<$nthreads>. The current |
758 | is C<4>, which means four asynchronous operations can be done at one time |
758 | default is C<8>, which means eight asynchronous operations can execute |
759 | (the number of outstanding operations, however, is unlimited). |
759 | concurrently at any one time (the number of outstanding requests, |
|
|
760 | however, is unlimited). |
760 | |
761 | |
761 | IO::AIO starts threads only on demand, when an AIO request is queued and |
762 | IO::AIO starts threads only on demand, when an AIO request is queued and |
762 | no free thread exists. |
763 | no free thread exists. |
763 | |
764 | |
764 | It is recommended to keep the number of threads low, as some Linux |
765 | It is recommended to keep the number of threads relatively low, as some |
765 | kernel versions will scale negatively with the number of threads (higher |
766 | Linux kernel versions will scale negatively with the number of threads |
766 | parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32 |
767 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
767 | threads should be fine. |
768 | versions, 4-32 threads should be fine. |
768 | |
769 | |
769 | Under most circumstances you don't need to call this function, as the |
770 | Under most circumstances you don't need to call this function, as the |
770 | module selects a default that is suitable for low to moderate load. |
771 | module selects a default that is suitable for low to moderate load. |
771 | |
772 | |
772 | =item IO::AIO::max_parallel $nthreads |
773 | =item IO::AIO::max_parallel $nthreads |
… | |
… | |
813 | or return undef; |
814 | or return undef; |
814 | |
815 | |
815 | *$sym |
816 | *$sym |
816 | } |
817 | } |
817 | |
818 | |
818 | min_parallel 4; |
819 | min_parallel 8; |
819 | |
820 | |
820 | END { |
821 | END { |
821 | max_parallel 0; |
822 | max_parallel 0; |
822 | } |
823 | } |
823 | |
824 | |