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Revision 1.9 by root, Sun Jul 10 22:20:55 2005 UTC vs.
Revision 1.40 by root, Tue Aug 30 15:45:10 2005 UTC

… …
22 poll => 'r', 22 poll => 'r',
23 cb => \&IO::AIO::poll_cb); 23 cb => \&IO::AIO::poll_cb);
24 24
25 # Glib/Gtk2 25 # Glib/Gtk2
26 add_watch Glib::IO IO::AIO::poll_fileno, 26 add_watch Glib::IO IO::AIO::poll_fileno,
27 \&IO::AIO::poll_cb; 27 in => sub { IO::AIO::poll_cb; 1 };
28 28
29 # Tk 29 # Tk
30 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", 30 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
31 readable => \&IO::AIO::poll_cb); 31 readable => \&IO::AIO::poll_cb);
32
33 # Danga::Socket
34 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
35 \&IO::AIO::poll_cb);
36
32 37
33=head1 DESCRIPTION 38=head1 DESCRIPTION
34 39
35This module implements asynchronous I/O using whatever means your 40This module implements asynchronous I/O using whatever means your
36operating system supports. 41operating system supports.
… …
43not well-supported (Linux doesn't allow them on normal files currently, 48not well-supported (Linux doesn't allow them on normal files currently,
44for example), and they would only support aio_read and aio_write, so the 49for example), and they would only support aio_read and aio_write, so the
45remaining functionality would have to be implemented using threads anyway. 50remaining functionality would have to be implemented using threads anyway.
46 51
47Although the module will work with in the presence of other threads, it is 52Although the module will work with in the presence of other threads, it is
48currently not reentrant, so use appropriate locking yourself. 53currently not reentrant, so use appropriate locking yourself, always call
54C<poll_cb> from within the same thread, or never call C<poll_cb> (or other
55C<aio_> functions) recursively.
49 56
50=cut 57=cut
51 58
52package IO::AIO; 59package IO::AIO;
53 60
61no warnings;
62
54use base 'Exporter'; 63use base 'Exporter';
55 64
56use Fcntl (); 65use Fcntl ();
57 66
58BEGIN { 67BEGIN {
59 $VERSION = 0.2; 68 $VERSION = 1.6;
60 69
61 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink 70 @EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
71 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
62 aio_fsync aio_fdatasync aio_readahead); 72 aio_fsync aio_fdatasync aio_readahead);
63 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); 73 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel
74 max_outstanding nreqs);
64 75
65 require XSLoader; 76 require XSLoader;
66 XSLoader::load IO::AIO, $VERSION; 77 XSLoader::load IO::AIO, $VERSION;
67} 78}
68 79
… …
70 81
71=head2 AIO FUNCTIONS 82=head2 AIO FUNCTIONS
72 83
73All the C<aio_*> calls are more or less thin wrappers around the syscall 84All the C<aio_*> calls are more or less thin wrappers around the syscall
74with the same name (sans C<aio_>). The arguments are similar or identical, 85with the same name (sans C<aio_>). The arguments are similar or identical,
75and they all accept an additional C<$callback> argument which must be 86and they all accept an additional (and optional) C<$callback> argument
76a code reference. This code reference will get called with the syscall 87which must be a code reference. This code reference will get called with
77return code (e.g. most syscalls return C<-1> on error, unlike perl, which 88the syscall return code (e.g. most syscalls return C<-1> on error, unlike
78usually delivers "false") as it's sole argument when the given syscall has 89perl, which usually delivers "false") as it's sole argument when the given
79been executed asynchronously. 90syscall has been executed asynchronously.
80 91
81All functions that expect a filehandle will also accept a file descriptor. 92All functions expecting a filehandle keep a copy of the filehandle
93internally until the request has finished.
82 94
83The filenames you pass to these routines I<must> be absolute. The reason 95The pathnames you pass to these routines I<must> be absolute and
84is that at the time the request is being executed, the current working 96encoded in byte form. The reason for the former is that at the time the
85directory could have changed. Alternatively, you can make sure that you 97request is being executed, the current working directory could have
98changed. Alternatively, you can make sure that you never change the
86never change the current working directory. 99current working directory.
100
101To encode pathnames to byte form, either make sure you either: a)
102always pass in filenames you got from outside (command line, readdir
103etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode
104your pathnames to the locale (or other) encoding in effect in the user
105environment, d) use Glib::filename_from_unicode on unicode filenames or e)
106use something else.
87 107
88=over 4 108=over 4
89 109
90=item aio_open $pathname, $flags, $mode, $callback 110=item aio_open $pathname, $flags, $mode, $callback->($fh)
91 111
92Asynchronously open or create a file and call the callback with a newly 112Asynchronously open or create a file and call the callback with a newly
93created filehandle for the file. 113created filehandle for the file.
94 114
95The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 115The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
96for an explanation. 116for an explanation.
97 117
98The C<$mode> argument is a bitmask. See the C<Fcntl> module for a 118The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
99list. They are the same as used in C<sysopen>. 119list. They are the same as used by C<sysopen>.
120
121Likewise, C<$mode> specifies the mode of the newly created file, if it
122didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
123except that it is mandatory (i.e. use C<0> if you don't create new files,
124and C<0666> or C<0777> if you do).
100 125
101Example: 126Example:
102 127
103 aio_open "/etc/passwd", O_RDONLY, 0, sub { 128 aio_open "/etc/passwd", O_RDONLY, 0, sub {
104 if ($_[0]) { 129 if ($_[0]) {
… …
107 } else { 132 } else {
108 die "open failed: $!\n"; 133 die "open failed: $!\n";
109 } 134 }
110 }; 135 };
111 136
112=item aio_close $fh, $callback 137=item aio_close $fh, $callback->($status)
113 138
114Asynchronously close a file and call the callback with the result 139Asynchronously close a file and call the callback with the result
115code. I<WARNING:> although accepted, you should not pass in a perl 140code. I<WARNING:> although accepted, you should not pass in a perl
116filehandle here, as perl will likely close the file descriptor itself when 141filehandle here, as perl will likely close the file descriptor another
117the filehandle is destroyed. Normally, you can safely call perls C<close> 142time when the filehandle is destroyed. Normally, you can safely call perls
118or just let filehandles go out of scope. 143C<close> or just let filehandles go out of scope.
119 144
145This is supposed to be a bug in the API, so that might change. It's
146therefore best to avoid this function.
147
120=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback 148=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
121 149
122=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback 150=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
123 151
124Reads or writes C<length> bytes from the specified C<fh> and C<offset> 152Reads or writes C<length> bytes from the specified C<fh> and C<offset>
125into the scalar given by C<data> and offset C<dataoffset> and calls the 153into the scalar given by C<data> and offset C<dataoffset> and calls the
126callback without the actual number of bytes read (or -1 on error, just 154callback without the actual number of bytes read (or -1 on error, just
127like the syscall). 155like the syscall).
128 156
157The C<$data> scalar I<MUST NOT> be modified in any way while the request
158is outstanding. Modifying it can result in segfaults or WW3 (if the
159necessary/optional hardware is installed).
160
129Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at 161Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
130offset C<0> within the scalar: 162offset C<0> within the scalar:
131 163
132 aio_read $fh, 7, 15, $buffer, 0, sub { 164 aio_read $fh, 7, 15, $buffer, 0, sub {
133 $_[0] > 0 or die "read error: $!"; 165 $_[0] > 0 or die "read error: $!";
134 print "read $_[0] bytes: <$buffer>\n"; 166 print "read $_[0] bytes: <$buffer>\n";
135 }; 167 };
136 168
169=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
170
171Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
172reading at byte offset C<$in_offset>, and starts writing at the current
173file offset of C<$out_fh>. Because of that, it is not safe to issue more
174than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
175other.
176
177This call tries to make use of a native C<sendfile> syscall to provide
178zero-copy operation. For this to work, C<$out_fh> should refer to a
179socket, and C<$in_fh> should refer to mmap'able file.
180
181If the native sendfile call fails or is not implemented, it will be
182emulated, so you can call C<aio_sendfile> on any type of filehandle
183regardless of the limitations of the operating system.
184
185Please note, however, that C<aio_sendfile> can read more bytes from
186C<$in_fh> than are written, and there is no way to find out how many
187bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
188provides the number of bytes written to C<$out_fh>. Only if the result
189value equals C<$length> one can assume that C<$length> bytes have been
190read.
191
137=item aio_readahead $fh,$offset,$length, $callback 192=item aio_readahead $fh,$offset,$length, $callback->($retval)
138 193
139Asynchronously reads the specified byte range into the page cache, using
140the C<readahead> syscall. If that syscall doesn't exist the status will be
141C<-1> and C<$!> is set to ENOSYS.
142
143readahead() populates the page cache with data from a file so that 194C<aio_readahead> populates the page cache with data from a file so that
144subsequent reads from that file will not block on disk I/O. The C<$offset> 195subsequent reads from that file will not block on disk I/O. The C<$offset>
145argument specifies the starting point from which data is to be read and 196argument specifies the starting point from which data is to be read and
146C<$length> specifies the number of bytes to be read. I/O is performed in 197C<$length> specifies the number of bytes to be read. I/O is performed in
147whole pages, so that offset is effectively rounded down to a page boundary 198whole pages, so that offset is effectively rounded down to a page boundary
148and bytes are read up to the next page boundary greater than or equal to 199and bytes are read up to the next page boundary greater than or equal to
149(off-set+length). aio_readahead() does not read beyond the end of the 200(off-set+length). C<aio_readahead> does not read beyond the end of the
150file. The current file offset of the file is left unchanged. 201file. The current file offset of the file is left unchanged.
151 202
203If that syscall doesn't exist (likely if your OS isn't Linux) it will be
204emulated by simply reading the data, which would have a similar effect.
205
152=item aio_stat $fh_or_path, $callback 206=item aio_stat $fh_or_path, $callback->($status)
153 207
154=item aio_lstat $fh, $callback 208=item aio_lstat $fh, $callback->($status)
155 209
156Works like perl's C<stat> or C<lstat> in void context. The callback will 210Works like perl's C<stat> or C<lstat> in void context. The callback will
157be called after the stat and the results will be available using C<stat _> 211be called after the stat and the results will be available using C<stat _>
158or C<-s _> etc... 212or C<-s _> etc...
159 213
… …
169 aio_stat "/etc/passwd", sub { 223 aio_stat "/etc/passwd", sub {
170 $_[0] and die "stat failed: $!"; 224 $_[0] and die "stat failed: $!";
171 print "size is ", -s _, "\n"; 225 print "size is ", -s _, "\n";
172 }; 226 };
173 227
174=item aio_unlink $pathname, $callback 228=item aio_unlink $pathname, $callback->($status)
175 229
176Asynchronously unlink (delete) a file and call the callback with the 230Asynchronously unlink (delete) a file and call the callback with the
177result code. 231result code.
178 232
233=item aio_rmdir $pathname, $callback->($status)
234
235Asynchronously rmdir (delete) a directory and call the callback with the
236result code.
237
238=item aio_readdir $pathname $callback->($entries)
239
240Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
241directory (i.e. opendir + readdir + closedir). The entries will not be
242sorted, and will B<NOT> include the C<.> and C<..> entries.
243
244The callback a single argument which is either C<undef> or an array-ref
245with the filenames.
246
247=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
248
249Scans a directory (similar to C<aio_readdir>) and tries to separate the
250entries of directory C<$path> into two sets of names, ones you can recurse
251into (directories), and ones you cannot recurse into (everything else).
252
253C<aio_scandir> is a composite request that consists of many
254aio-primitives. C<$maxreq> specifies the maximum number of outstanding
255aio requests that this function generates. If it is C<< <= 0 >>, then a
256suitable default will be chosen (currently 8).
257
258On error, the callback is called without arguments, otherwise it receives
259two array-refs with path-relative entry names.
260
261Example:
262
263 aio_scandir $dir, 0, sub {
264 my ($dirs, $nondirs) = @_;
265 print "real directories: @$dirs\n";
266 print "everything else: @$nondirs\n";
267 };
268
269Implementation notes.
270
271The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
272
273After reading the directory, the modification time, size etc. of the
274directory before and after the readdir is checked, and if they match, the
275link count will be used to decide how many entries are directories (if
276>= 2). Otherwise, no knowledge of the number of subdirectories will be
277assumed.
278
279Then entires will be sorted into likely directories (everything without a
280non-initial dot) and likely non-directories (everything else). Then every
281entry + C</.> will be C<stat>'ed, likely directories first. This is often
282faster because filesystems might detect the type of the entry without
283reading the inode data (e.g. ext2s filetype feature). If that succeeds,
284it assumes that the entry is a directory or a symlink to directory (which
285will be checked seperately).
286
287If the known number of directories has been reached, the rest of the
288entries is assumed to be non-directories.
289
290=cut
291
292sub aio_scandir($$$) {
293 my ($path, $maxreq, $cb) = @_;
294
295 $maxreq = 8 if $maxreq <= 0;
296
297 # stat once
298 aio_stat $path, sub {
299 $cb->() if $_[0];
300 my $hash1 = join ":", (stat _)[0,1,3,7,9];
301
302 # read the directory entries
303 aio_readdir $path, sub {
304 my $entries = shift
305 or return $cb->();
306
307 # stat the dir another time
308 aio_stat $path, sub {
309 my $hash2 = join ":", (stat _)[0,1,3,7,9];
310
311 my $ndirs;
312
313 # take the slow route if anything looks fishy
314 if ($hash1 ne $hash2) {
315 $ndirs = -1;
316 } else {
317 # if nlink == 2, we are finished
318 # on non-posix-fs's, we rely on nlink < 2
319 $ndirs = (stat _)[3] - 2
320 or $cb->([], $entries);
321 }
322
323 # sort into likely dirs and likely nondirs
324 # dirs == files without ".", short entries first
325 $entries = [map $_->[0],
326 sort { $b->[1] cmp $a->[1] }
327 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
328 @$entries];
329
330 my (@dirs, @nondirs);
331
332 my ($statcb, $schedcb);
333 my $nreq = 0;
334
335 $schedcb = sub {
336 if (@$entries) {
337 if ($nreq < $maxreq) {
338 my $ent = pop @$entries;
339 $nreq++;
340 aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
341 }
342 } elsif (!$nreq) {
343 # finished
344 undef $statcb;
345 undef $schedcb;
346 $cb->(\@dirs, \@nondirs);
347 undef $cb;
348 }
349 };
350 $statcb = sub {
351 my ($status, $entry) = @_;
352
353 if ($status < 0) {
354 $nreq--;
355 push @nondirs, $entry;
356 &$schedcb;
357 } else {
358 # need to check for real directory
359 aio_lstat "$path/$entry", sub {
360 $nreq--;
361
362 if (-d _) {
363 push @dirs, $entry;
364
365 if (!--$ndirs) {
366 push @nondirs, @$entries;
367 $entries = [];
368 }
369 } else {
370 push @nondirs, $entry;
371 }
372
373 &$schedcb;
374 }
375 }
376 };
377
378 &$schedcb while @$entries && $nreq < $maxreq;
379 };
380 };
381 };
382}
383
179=item aio_fsync $fh, $callback 384=item aio_fsync $fh, $callback->($status)
180 385
181Asynchronously call fsync on the given filehandle and call the callback 386Asynchronously call fsync on the given filehandle and call the callback
182with the fsync result code. 387with the fsync result code.
183 388
184=item aio_fdatasync $fh, $callback 389=item aio_fdatasync $fh, $callback->($status)
185 390
186Asynchronously call fdatasync on the given filehandle and call the 391Asynchronously call fdatasync on the given filehandle and call the
187callback with the fdatasync result code. 392callback with the fdatasync result code.
188 393
394If this call isn't available because your OS lacks it or it couldn't be
395detected, it will be emulated by calling C<fsync> instead.
396
189=back 397=back
190 398
191=head2 SUPPORT FUNCTIONS 399=head2 SUPPORT FUNCTIONS
192 400
193=over 4 401=over 4
194 402
195=item $fileno = IO::AIO::poll_fileno 403=item $fileno = IO::AIO::poll_fileno
196 404
197Return the I<request result pipe filehandle>. This filehandle must be 405Return the I<request result pipe file descriptor>. This filehandle must be
198polled for reading by some mechanism outside this module (e.g. Event 406polled for reading by some mechanism outside this module (e.g. Event or
199or select, see below). If the pipe becomes readable you have to call 407select, see below or the SYNOPSIS). If the pipe becomes readable you have
200C<poll_cb> to check the results. 408to call C<poll_cb> to check the results.
201 409
202See C<poll_cb> for an example. 410See C<poll_cb> for an example.
203 411
204=item IO::AIO::poll_cb 412=item IO::AIO::poll_cb
205 413
206Process all outstanding events on the result pipe. You have to call this 414Process all outstanding events on the result pipe. You have to call this
207regularly. Returns the number of events processed. Returns immediately 415regularly. Returns the number of events processed. Returns immediately
208when no events are outstanding. 416when no events are outstanding.
209 417
210You can use Event to multiplex, e.g.: 418Example: Install an Event watcher that automatically calls
419IO::AIO::poll_cb with high priority:
211 420
212 Event->io (fd => IO::AIO::poll_fileno, 421 Event->io (fd => IO::AIO::poll_fileno,
213 poll => 'r', async => 1, 422 poll => 'r', async => 1,
214 cb => \&IO::AIO::poll_cb); 423 cb => \&IO::AIO::poll_cb);
215 424
216=item IO::AIO::poll_wait 425=item IO::AIO::poll_wait
217 426
218Wait till the result filehandle becomes ready for reading (simply does a 427Wait till the result filehandle becomes ready for reading (simply does a
219select on the filehandle. This is useful if you want to synchronously wait 428C<select> on the filehandle. This is useful if you want to synchronously wait
220for some requests to finish). 429for some requests to finish).
221 430
222See C<nreqs> for an example. 431See C<nreqs> for an example.
223 432
224=item IO::AIO::nreqs 433=item IO::AIO::nreqs
225 434
226Returns the number of requests currently outstanding. 435Returns the number of requests currently outstanding (i.e. for which their
436callback has not been invoked yet).
227 437
228Example: wait till there are no outstanding requests anymore: 438Example: wait till there are no outstanding requests anymore:
229 439
230 IO::AIO::poll_wait, IO::AIO::poll_cb 440 IO::AIO::poll_wait, IO::AIO::poll_cb
231 while IO::AIO::nreqs; 441 while IO::AIO::nreqs;
232 442
443=item IO::AIO::flush
444
445Wait till all outstanding AIO requests have been handled.
446
447Strictly equivalent to:
448
449 IO::AIO::poll_wait, IO::AIO::poll_cb
450 while IO::AIO::nreqs;
451
452=item IO::AIO::poll
453
454Waits until some requests have been handled.
455
456Strictly equivalent to:
457
458 IO::AIO::poll_wait, IO::AIO::poll_cb
459 if IO::AIO::nreqs;
460
233=item IO::AIO::min_parallel $nthreads 461=item IO::AIO::min_parallel $nthreads
234 462
235Set the minimum number of AIO threads to C<$nthreads>. The default is 463Set the minimum number of AIO threads to C<$nthreads>. The current default
236C<1>, which means a single asynchronous operation can be done at one time 464is C<4>, which means four asynchronous operations can be done at one time
237(the number of outstanding operations, however, is unlimited). 465(the number of outstanding operations, however, is unlimited).
466
467IO::AIO starts threads only on demand, when an AIO request is queued and
468no free thread exists.
238 469
239It is recommended to keep the number of threads low, as some Linux 470It is recommended to keep the number of threads low, as some Linux
240kernel versions will scale negatively with the number of threads (higher 471kernel versions will scale negatively with the number of threads (higher
241parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32 472parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32
242threads should be fine. 473threads should be fine.
243 474
244Under normal circumstances you don't need to call this function, as this 475Under most circumstances you don't need to call this function, as the
245module automatically starts some threads (the exact number might change, 476module selects a default that is suitable for low to moderate load.
246and is currently 4).
247 477
248=item IO::AIO::max_parallel $nthreads 478=item IO::AIO::max_parallel $nthreads
249 479
250Sets the maximum number of AIO threads to C<$nthreads>. If more than 480Sets the maximum number of AIO threads to C<$nthreads>. If more than the
251the specified number of threads are currently running, kill them. This 481specified number of threads are currently running, this function kills
252function blocks until the limit is reached. 482them. This function blocks until the limit is reached.
483
484While C<$nthreads> are zero, aio requests get queued but not executed
485until the number of threads has been increased again.
253 486
254This module automatically runs C<max_parallel 0> at program end, to ensure 487This module automatically runs C<max_parallel 0> at program end, to ensure
255that all threads are killed and that there are no outstanding requests. 488that all threads are killed and that there are no outstanding requests.
256 489
257Under normal circumstances you don't need to call this function. 490Under normal circumstances you don't need to call this function.
… …
261Sets the maximum number of outstanding requests to C<$nreqs>. If you 494Sets the maximum number of outstanding requests to C<$nreqs>. If you
262try to queue up more than this number of requests, the caller will block until 495try to queue up more than this number of requests, the caller will block until
263some requests have been handled. 496some requests have been handled.
264 497
265The default is very large, so normally there is no practical limit. If you 498The default is very large, so normally there is no practical limit. If you
266queue up many requests in a loop it it often improves speed if you set 499queue up many requests in a loop it often improves speed if you set
267this to a relatively low number, such as C<100>. 500this to a relatively low number, such as C<100>.
268 501
269Under normal circumstances you don't need to call this function. 502Under normal circumstances you don't need to call this function.
270 503
271=back 504=back
… …
274 507
275# support function to convert a fd into a perl filehandle 508# support function to convert a fd into a perl filehandle
276sub _fd2fh { 509sub _fd2fh {
277 return undef if $_[0] < 0; 510 return undef if $_[0] < 0;
278 511
279 # try to be perl5.6-compatible 512 # try to generate nice filehandles
280 local *AIO_FH; 513 my $sym = "IO::AIO::fd#$_[0]";
281 open AIO_FH, "+<&=$_[0]" 514 local *$sym;
515
516 open *$sym, "+<&=$_[0]" # usually works under any unix
517 or open *$sym, "<&=$_[0]" # cygwin needs this
518 or open *$sym, ">&=$_[0]" # or this
282 or return undef; 519 or return undef;
283 520
284 *AIO_FH 521 *$sym
285} 522}
286 523
287min_parallel 4; 524min_parallel 4;
288 525
289END { 526END {
290 max_parallel 0; 527 max_parallel 0;
291} 528}
292 529
2931; 5301;
294 531
532=head2 FORK BEHAVIOUR
533
534Before the fork, IO::AIO enters a quiescent state where no requests
535can be added in other threads and no results will be processed. After
536the fork the parent simply leaves the quiescent state and continues
537request/result processing, while the child clears the request/result
538queue (so the requests started before the fork will only be handled in
539the parent). Threats will be started on demand until the limit ste in the
540parent process has been reached again.
541
295=head1 SEE ALSO 542=head1 SEE ALSO
296 543
297L<Coro>, L<Linux::AIO>. 544L<Coro>, L<Linux::AIO>.
298 545
299=head1 AUTHOR 546=head1 AUTHOR

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