[ViewVC] Diff of: cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.84 by root, Fri Apr 25 13:48:42 2008 UTC vs.
Revision 1.102 by root, Sun Apr 27 21:16:26 2008 UTC

…		…
65	technically possible.	65	technically possible.
66		66
67	Of course, if you want lots of policy (this can arguably be somewhat	67	Of course, if you want lots of policy (this can arguably be somewhat
68	useful) and you want to force your users to use the one and only event	68	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	69	model, you should I<not> use this module.
70
71		70
72	=head1 DESCRIPTION	71	=head1 DESCRIPTION
73		72
74	L<AnyEvent> provides an identical interface to multiple event loops. This	73	L<AnyEvent> provides an identical interface to multiple event loops. This
75	allows module authors to utilise an event loop without forcing module	74	allows module authors to utilise an event loop without forcing module
…		…
141	=head2 I/O WATCHERS	140	=head2 I/O WATCHERS
142		141
143	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	142	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
144	with the following mandatory key-value pairs as arguments:	143	with the following mandatory key-value pairs as arguments:
145		144
146	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for	145	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch
147	events. C<poll> must be a string that is either C<r> or C<w>, which	146	for events. C<poll> must be a string that is either C<r> or C<w>,
148	creates a watcher waiting for "r"eadable or "w"ritable events,	147	which creates a watcher waiting for "r"eadable or "w"ritable events,
149	respectively. C<cb> is the callback to invoke each time the file handle	148	respectively. C<cb> is the callback to invoke each time the file handle
150	becomes ready.	149	becomes ready.
		150
		151	Although the callback might get passed parameters, their value and
		152	presence is undefined and you cannot rely on them. Portable AnyEvent
		153	callbacks cannot use arguments passed to I/O watcher callbacks.
151		154
152	The I/O watcher might use the underlying file descriptor or a copy of it.	155	The I/O watcher might use the underlying file descriptor or a copy of it.
153	You must not close a file handle as long as any watcher is active on the	156	You must not close a file handle as long as any watcher is active on the
154	underlying file descriptor.	157	underlying file descriptor.
155		158
156	Some event loops issue spurious readyness notifications, so you should	159	Some event loops issue spurious readyness notifications, so you should
157	always use non-blocking calls when reading/writing from/to your file	160	always use non-blocking calls when reading/writing from/to your file
158	handles.	161	handles.
159
160	Although the callback might get passed parameters, their value and
161	presence is undefined and you cannot rely on them. Portable AnyEvent
162	callbacks cannot use arguments passed to I/O watcher callbacks.
163		162
164	Example:	163	Example:
165		164
166	# wait for readability of STDIN, then read a line and disable the watcher	165	# wait for readability of STDIN, then read a line and disable the watcher
167	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	166	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
…		…
174		173
175	You can create a time watcher by calling the C<< AnyEvent->timer >>	174	You can create a time watcher by calling the C<< AnyEvent->timer >>
176	method with the following mandatory arguments:	175	method with the following mandatory arguments:
177		176
178	C<after> specifies after how many seconds (fractional values are	177	C<after> specifies after how many seconds (fractional values are
179	supported) should the timer activate. C<cb> the callback to invoke in that	178	supported) the callback should be invoked. C<cb> is the callback to invoke
180	case.	179	in that case.
		180
		181	Although the callback might get passed parameters, their value and
		182	presence is undefined and you cannot rely on them. Portable AnyEvent
		183	callbacks cannot use arguments passed to time watcher callbacks.
181		184
182	The timer callback will be invoked at most once: if you want a repeating	185	The timer callback will be invoked at most once: if you want a repeating
183	timer you have to create a new watcher (this is a limitation by both Tk	186	timer you have to create a new watcher (this is a limitation by both Tk
184	and Glib).	187	and Glib).
185
186	Although the callback might get passed parameters, their value and
187	presence is undefined and you cannot rely on them. Portable AnyEvent
188	callbacks cannot use arguments passed to time watcher callbacks.
189		188
190	Example:	189	Example:
191		190
192	# fire an event after 7.7 seconds	191	# fire an event after 7.7 seconds
193	my $w = AnyEvent->timer (after => 7.7, cb => sub {	192	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
234		233
235	You can watch for signals using a signal watcher, C<signal> is the signal	234	You can watch for signals using a signal watcher, C<signal> is the signal
236	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	235	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
237	be invoked whenever a signal occurs.	236	be invoked whenever a signal occurs.
238		237
		238	Although the callback might get passed parameters, their value and
		239	presence is undefined and you cannot rely on them. Portable AnyEvent
		240	callbacks cannot use arguments passed to signal watcher callbacks.
		241
239	Multiple signal occurances can be clumped together into one callback	242	Multiple signal occurances can be clumped together into one callback
240	invocation, and callback invocation will be synchronous. synchronous means	243	invocation, and callback invocation will be synchronous. synchronous means
241	that it might take a while until the signal gets handled by the process,	244	that it might take a while until the signal gets handled by the process,
242	but it is guarenteed not to interrupt any other callbacks.	245	but it is guarenteed not to interrupt any other callbacks.
243		246
…		…
257		260
258	The child process is specified by the C<pid> argument (if set to C<0>, it	261	The child process is specified by the C<pid> argument (if set to C<0>, it
259	watches for any child process exit). The watcher will trigger as often	262	watches for any child process exit). The watcher will trigger as often
260	as status change for the child are received. This works by installing a	263	as status change for the child are received. This works by installing a
261	signal handler for C<SIGCHLD>. The callback will be called with the pid	264	signal handler for C<SIGCHLD>. The callback will be called with the pid
262	and exit status (as returned by waitpid).	265	and exit status (as returned by waitpid), so unlike other watcher types,
		266	you I<can> rely on child watcher callback arguments.
263		267
264	There is a slight catch to child watchers, however: you usually start them	268	There is a slight catch to child watchers, however: you usually start them
265	I<after> the child process was created, and this means the process could	269	I<after> the child process was created, and this means the process could
266	have exited already (and no SIGCHLD will be sent anymore).	270	have exited already (and no SIGCHLD will be sent anymore).
267		271
…		…
452	might chose the wrong one unless you load the correct one yourself.	456	might chose the wrong one unless you load the correct one yourself.
453		457
454	You can chose to use a rather inefficient pure-perl implementation by	458	You can chose to use a rather inefficient pure-perl implementation by
455	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	459	loading the C<AnyEvent::Impl::Perl> module, which gives you similar
456	behaviour everywhere, but letting AnyEvent chose is generally better.	460	behaviour everywhere, but letting AnyEvent chose is generally better.
		461
		462	=head1 OTHER MODULES
		463
		464	The following is a non-exhaustive list of additional modules that use
		465	AnyEvent and can therefore be mixed easily with other AnyEvent modules
		466	in the same program. Some of the modules come with AnyEvent, some are
		467	available via CPAN.
		468
		469	=over 4
		470
		471	=item L<AnyEvent::Util>
		472
		473	Contains various utility functions that replace often-used but blocking
		474	functions such as C<inet_aton> by event-/callback-based versions.
		475
		476	=item L<AnyEvent::Handle>
		477
		478	Provide read and write buffers and manages watchers for reads and writes.
		479
		480	=item L<AnyEvent::Socket>
		481
		482	Provides a means to do non-blocking connects, accepts etc.
		483
		484	=item L<AnyEvent::HTTPD>
		485
		486	Provides a simple web application server framework.
		487
		488	=item L<AnyEvent::DNS>
		489
		490	Provides asynchronous DNS resolver capabilities, beyond what
		491	L<AnyEvent::Util> offers.
		492
		493	=item L<AnyEvent::FastPing>
		494
		495	The fastest ping in the west.
		496
		497	=item L<Net::IRC3>
		498
		499	AnyEvent based IRC client module family.
		500
		501	=item L<Net::XMPP2>
		502
		503	AnyEvent based XMPP (Jabber protocol) module family.
		504
		505	=item L<Net::FCP>
		506
		507	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
		508	of AnyEvent.
		509
		510	=item L<Event::ExecFlow>
		511
		512	High level API for event-based execution flow control.
		513
		514	=item L<Coro>
		515
		516	Has special support for AnyEvent.
		517
		518	=item L<IO::Lambda>
		519
		520	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
		521
		522	=item L<IO::AIO>
		523
		524	Truly asynchronous I/O, should be in the toolbox of every event
		525	programmer. Can be trivially made to use AnyEvent.
		526
		527	=item L<BDB>
		528
		529	Truly asynchronous Berkeley DB access. Can be trivially made to use
		530	AnyEvent.
		531
		532	=back
457		533
458	=cut	534	=cut
459		535
460	package AnyEvent;	536	package AnyEvent;
461		537
…		…
889	});	965	});
890		966
891	$quit->wait;	967	$quit->wait;
892		968
893		969
894	=head1 BENCHMARK	970	=head1 BENCHMARKS
895		971
896	To give you an idea of the performance and overheads that AnyEvent adds	972	To give you an idea of the performance and overheads that AnyEvent adds
897	over the event loops themselves (and to give you an impression of the	973	over the event loops themselves and to give you an impression of the speed
898	speed of various event loops), here is a benchmark of various supported	974	of various event loops I prepared some benchmarks.
899	event models natively and with anyevent. The benchmark creates a lot of	975
900	timers (with a zero timeout) and I/O watchers (watching STDOUT, a pty, to	976	=head2 BENCHMARKING ANYEVENT OVERHEAD
		977
		978	Here is a benchmark of various supported event models used natively and
		979	through anyevent. The benchmark creates a lot of timers (with a zero
		980	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
901	become writable, which it is), lets them fire exactly once and destroys	981	which it is), lets them fire exactly once and destroys them again.
902	them again.
903		982
904	Rewriting the benchmark to use many different sockets instead of using	983	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
905	the same filehandle for all I/O watchers results in a much longer runtime	984	distribution.
906	(socket creation is expensive), but qualitatively the same figures, so it
907	was not used.
908		985
909	=head2 Explanation of the columns	986	=head3 Explanation of the columns
910		987
911	I<watcher> is the number of event watchers created/destroyed. Since	988	I<watcher> is the number of event watchers created/destroyed. Since
912	different event models feature vastly different performances, each event	989	different event models feature vastly different performances, each event
913	loop was given a number of watchers so that overall runtime is acceptable	990	loop was given a number of watchers so that overall runtime is acceptable
914	and similar between tested event loop (and keep them from crashing): Glib	991	and similar between tested event loop (and keep them from crashing): Glib
…		…
930	signal the end of this phase.	1007	signal the end of this phase.
931		1008
932	I<destroy> is the time, in microseconds, that it takes to destroy a single	1009	I<destroy> is the time, in microseconds, that it takes to destroy a single
933	watcher.	1010	watcher.
934		1011
935	=head2 Results	1012	=head3 Results
936		1013
937	name watchers bytes create invoke destroy comment	1014	name watchers bytes create invoke destroy comment
938	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1015	EV/EV 400000 244 0.56 0.46 0.31 EV native interface
939	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1016	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers
940	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1017	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal
941	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1018	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation
942	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1019	Event/Event 16000 516 31.88 31.30 0.85 Event native interface
943	Event/Any 16000 936 39.17 33.63 1.43 Event + AnyEvent watchers	1020	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers
944	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1021	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour
945	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1022	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers
946	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1023	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event
947	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1024	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select
948		1025
949	=head2 Discussion	1026	=head3 Discussion
950		1027
951	The benchmark does I<not> measure scalability of the event loop very	1028	The benchmark does I<not> measure scalability of the event loop very
952	well. For example, a select-based event loop (such as the pure perl one)	1029	well. For example, a select-based event loop (such as the pure perl one)
953	can never compete with an event loop that uses epoll when the number of	1030	can never compete with an event loop that uses epoll when the number of
954	file descriptors grows high. In this benchmark, all events become ready at	1031	file descriptors grows high. In this benchmark, all events become ready at
955	the same time, so select/poll-based implementations get an unnatural speed	1032	the same time, so select/poll-based implementations get an unnatural speed
956	boost.	1033	boost.
957		1034
		1035	Also, note that the number of watchers usually has a nonlinear effect on
		1036	overall speed, that is, creating twice as many watchers doesn't take twice
		1037	the time - usually it takes longer. This puts event loops tested with a
		1038	higher number of watchers at a disadvantage.
		1039
		1040	To put the range of results into perspective, consider that on the
		1041	benchmark machine, handling an event takes roughly 1600 CPU cycles with
		1042	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
		1043	cycles with POE.
		1044
958	C<EV> is the sole leader regarding speed and memory use, which are both	1045	C<EV> is the sole leader regarding speed and memory use, which are both
959	maximal/minimal, respectively. Even when going through AnyEvent, it uses	1046	maximal/minimal, respectively. Even when going through AnyEvent, it uses
960	far less memory than any other event loop and is still faster than Event	1047	far less memory than any other event loop and is still faster than Event
961	natively.	1048	natively.
962		1049
963	The pure perl implementation is hit in a few sweet spots (both the	1050	The pure perl implementation is hit in a few sweet spots (both the
964	zero timeout and the use of a single fd hit optimisations in the perl	1051	constant timeout and the use of a single fd hit optimisations in the perl
965	interpreter and the backend itself, and all watchers become ready at the	1052	interpreter and the backend itself). Nevertheless this shows that it
966	same time). Nevertheless this shows that it adds very little overhead in	1053	adds very little overhead in itself. Like any select-based backend its
967	itself. Like any select-based backend its performance becomes really bad	1054	performance becomes really bad with lots of file descriptors (and few of
968	with lots of file descriptors (and few of them active), of course, but	1055	them active), of course, but this was not subject of this benchmark.
969	this was not subject of this benchmark.
970		1056
971	The C<Event> module has a relatively high setup and callback invocation cost,	1057	The C<Event> module has a relatively high setup and callback invocation
972	but overall scores on the third place.	1058	cost, but overall scores in on the third place.
973		1059
974	C<Glib>'s memory usage is quite a bit bit higher, but it features a	1060	C<Glib>'s memory usage is quite a bit higher, but it features a
975	faster callback invocation and overall ends up in the same class as	1061	faster callback invocation and overall ends up in the same class as
976	C<Event>. However, Glib scales extremely badly, doubling the number of	1062	C<Event>. However, Glib scales extremely badly, doubling the number of
977	watchers increases the processing time by more than a factor of four,	1063	watchers increases the processing time by more than a factor of four,
978	making it completely unusable when using larger numbers of watchers	1064	making it completely unusable when using larger numbers of watchers
979	(note that only a single file descriptor was used in the benchmark, so	1065	(note that only a single file descriptor was used in the benchmark, so
…		…
982	The C<Tk> adaptor works relatively well. The fact that it crashes with	1068	The C<Tk> adaptor works relatively well. The fact that it crashes with
983	more than 2000 watchers is a big setback, however, as correctness takes	1069	more than 2000 watchers is a big setback, however, as correctness takes
984	precedence over speed. Nevertheless, its performance is surprising, as the	1070	precedence over speed. Nevertheless, its performance is surprising, as the
985	file descriptor is dup()ed for each watcher. This shows that the dup()	1071	file descriptor is dup()ed for each watcher. This shows that the dup()
986	employed by some adaptors is not a big performance issue (it does incur a	1072	employed by some adaptors is not a big performance issue (it does incur a
987	hidden memory cost inside the kernel, though, that is not reflected in the	1073	hidden memory cost inside the kernel which is not reflected in the figures
988	figures above).	1074	above).
989		1075
990	C<POE>, regardless of underlying event loop (wether using its pure perl	1076	C<POE>, regardless of underlying event loop (whether using its pure
991	select-based backend or the Event module) shows abysmal performance and	1077	perl select-based backend or the Event module, the POE-EV backend
		1078	couldn't be tested because it wasn't working) shows abysmal performance
992	memory usage: Watchers use almost 30 times as much memory as EV watchers,	1079	and memory usage: Watchers use almost 30 times as much memory as
993	and 10 times as much memory as both Event or EV via AnyEvent. Watcher	1080	EV watchers, and 10 times as much memory as Event (the high memory
		1081	requirements are caused by requiring a session for each watcher). Watcher
994	invocation is almost 900 times slower than with AnyEvent's pure perl	1082	invocation speed is almost 900 times slower than with AnyEvent's pure perl
995	implementation. The design of the POE adaptor class in AnyEvent can not	1083	implementation. The design of the POE adaptor class in AnyEvent can not
996	really account for this, as session creation overhead is small compared	1084	really account for this, as session creation overhead is small compared
997	to execution of the state machine, which is coded pretty optimally within	1085	to execution of the state machine, which is coded pretty optimally within
998	L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow.	1086	L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow.
999		1087
1000	=head2 Summary	1088	=head3 Summary
1001		1089
		1090	=over 4
		1091
1002	Using EV through AnyEvent is faster than any other event loop, but most	1092	=item * Using EV through AnyEvent is faster than any other event loop
1003	event loops have acceptable performance with or without AnyEvent.	1093	(even when used without AnyEvent), but most event loops have acceptable
		1094	performance with or without AnyEvent.
1004		1095
1005	The overhead AnyEvent adds is usually much smaller than the overhead of	1096	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
1006	the actual event loop, only with extremely fast event loops such as the EV	1097	the actual event loop, only with extremely fast event loops such as EV
1007	adds AnyEvent significant overhead.	1098	adds AnyEvent significant overhead.
1008		1099
1009	And you should simply avoid POE like the plague if you want performance or	1100	=item * You should avoid POE like the plague if you want performance or
1010	reasonable memory usage.	1101	reasonable memory usage.
		1102
		1103	=back
		1104
		1105	=head2 BENCHMARKING THE LARGE SERVER CASE
		1106
		1107	This benchmark atcually benchmarks the event loop itself. It works by
		1108	creating a number of "servers": each server consists of a socketpair, a
		1109	timeout watcher that gets reset on activity (but never fires), and an I/O
		1110	watcher waiting for input on one side of the socket. Each time the socket
		1111	watcher reads a byte it will write that byte to a random other "server".
		1112
		1113	The effect is that there will be a lot of I/O watchers, only part of which
		1114	are active at any one point (so there is a constant number of active
		1115	fds for each loop iterstaion, but which fds these are is random). The
		1116	timeout is reset each time something is read because that reflects how
		1117	most timeouts work (and puts extra pressure on the event loops).
		1118
		1119	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100
		1120	(1%) are active. This mirrors the activity of large servers with many
		1121	connections, most of which are idle at any one point in time.
		1122
		1123	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
		1124	distribution.
		1125
		1126	=head3 Explanation of the columns
		1127
		1128	I<sockets> is the number of sockets, and twice the number of "servers" (as
		1129	each server has a read and write socket end).
		1130
		1131	I<create> is the time it takes to create a socketpair (which is
		1132	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
		1133
		1134	I<request>, the most important value, is the time it takes to handle a
		1135	single "request", that is, reading the token from the pipe and forwarding
		1136	it to another server. This includes deleting the old timeout and creating
		1137	a new one that moves the timeout into the future.
		1138
		1139	=head3 Results
		1140
		1141	name sockets create request
		1142	EV 20000 69.01 11.16
		1143	Perl 20000 73.32 35.87
		1144	Event 20000 212.62 257.32
		1145	Glib 20000 651.16 1896.30
		1146	POE 20000 349.67 12317.24 uses POE::Loop::Event
		1147
		1148	=head3 Discussion
		1149
		1150	This benchmark I<does> measure scalability and overall performance of the
		1151	particular event loop.
		1152
		1153	EV is again fastest. Since it is using epoll on my system, the setup time
		1154	is relatively high, though.
		1155
		1156	Perl surprisingly comes second. It is much faster than the C-based event
		1157	loops Event and Glib.
		1158
		1159	Event suffers from high setup time as well (look at its code and you will
		1160	understand why). Callback invocation also has a high overhead compared to
		1161	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
		1162	uses select or poll in basically all documented configurations.
		1163
		1164	Glib is hit hard by its quadratic behaviour w.r.t. many watchers. It
		1165	clearly fails to perform with many filehandles or in busy servers.
		1166
		1167	POE is still completely out of the picture, taking over 1000 times as long
		1168	as EV, and over 100 times as long as the Perl implementation, even though
		1169	it uses a C-based event loop in this case.
		1170
		1171	=head3 Summary
		1172
		1173	=over 4
		1174
		1175	=item * The pure perl implementation performs extremely well, considering
		1176	that it uses select.
		1177
		1178	=item * Avoid Glib or POE in large projects where performance matters.
		1179
		1180	=back
		1181
		1182	=head2 BENCHMARKING SMALL SERVERS
		1183
		1184	While event loops should scale (and select-based ones do not...) even to
		1185	large servers, most programs we (or I :) actually write have only a few
		1186	I/O watchers.
		1187
		1188	In this benchmark, I use the same benchmark program as in the large server
		1189	case, but it uses only eight "servers", of which three are active at any
		1190	one time. This should reflect performance for a small server relatively
		1191	well.
		1192
		1193	The columns are identical to the previous table.
		1194
		1195	=head3 Results
		1196
		1197	name sockets create request
		1198	EV 16 20.00 6.54
		1199	Perl 16 25.75 12.62
		1200	Event 16 81.27 35.86
		1201	Glib 16 32.63 15.48
		1202	POE 16 261.87 276.28 uses POE::Loop::Event
		1203
		1204	=head3 Discussion
		1205
		1206	The benchmark tries to test the performance of a typical small
		1207	server. While knowing how various event loops perform is interesting, keep
		1208	in mind that their overhead in this case is usually not as important, due
		1209	to the small absolute number of watchers (that is, you need efficiency and
		1210	speed most when you have lots of watchers, not when you only have a few of
		1211	them).
		1212
		1213	EV is again fastest.
		1214
		1215	Perl again comes second. It is noticably faster than the C-based event
		1216	loops Event and Glib, although the difference is too small to really
		1217	matter.
		1218
		1219	POE also performs much better in this case, but is is still far behind the
		1220	others.
		1221
		1222	=head3 Summary
		1223
		1224	=over 4
		1225
		1226	=item * C-based event loops perform very well with small number of
		1227	watchers, as the management overhead dominates.
		1228
		1229	=back
1011		1230
1012		1231
1013	=head1 FORK	1232	=head1 FORK
1014		1233
1015	Most event libraries are not fork-safe. The ones who are usually are	1234	Most event libraries are not fork-safe. The ones who are usually are

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.84 by root, Fri Apr 25 13:48:42 2008 UTC vs. Revision 1.102 by root, Sun Apr 27 21:16:26 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.84 by root, Fri Apr 25 13:48:42 2008 UTC vs.
Revision 1.102 by root, Sun Apr 27 21:16:26 2008 UTC