[ViewVC] Diff of: cvs/AnyEvent-SNMP/SNMP.pm

Comparing AnyEvent-SNMP/SNMP.pm (file contents):
Revision 1.9 by root, Wed Jan 6 10:43:20 2010 UTC vs.
Revision 1.14 by root, Wed Oct 9 18:22:59 2019 UTC

…		…
23	my @result = $cv->wait;	23	my @result = $cv->wait;
24		24
25	=head1 DESCRIPTION	25	=head1 DESCRIPTION
26		26
27	This module implements an alternative "event dispatcher" for Net::SNMP,	27	This module implements an alternative "event dispatcher" for Net::SNMP,
28	using AnyEvent as a backend.	28	using AnyEvent as a backend. This integrates Net::SNMP into AnyEvent. That
29		29	means you can make non-blocking Net::SNMP calls and as long as other
30	This integrates Net::SNMP into AnyEvent: You can make non-blocking	30	parts of your program also use AnyEvent (or some event loop supported by
31	Net::SNMP calls and as long as other parts of your program also use	31	AnyEvent), they will run in parallel.
32	AnyEvent (or some event loop supported by AnyEvent), they will run in
33	parallel.
34		32
35	Also, the Net::SNMP scheduler is very inefficient with respect to both CPU	33	Also, the Net::SNMP scheduler is very inefficient with respect to both CPU
36	and memory usage. Most AnyEvent backends (including the pure-perl backend)	34	and memory usage. Most AnyEvent backends (including the pure-perl backend)
37	fare much better than the Net::SNMP dispatcher.	35	fare much better than the Net::SNMP dispatcher.
38		36
		37	Another major added feature of this module over Net::SNMP is automatic
		38	rate-adjustments: Net::SNMP is so slow that firing a few thousand
		39	requests can cause many timeouts simply because Net::SNMP cannot process
		40	the replies in time. This module automatically adapts the send rate to
		41	avoid false timeouts caused by slow reply processing.
		42
39	A potential disadvantage is that replacing the dispatcher is not at all	43	A potential disadvantage of this module is that replacing the dispatcher
40	a documented thing to do, so future changes in Net::SNP might break this	44	is not at all a documented thing to do, so future changes in Net::SNMP
41	module (or the many similar ones).	45	might break this module (or the many similar ones).
42		46
43	This module does not export anything and does not require you to do	47	This module does not export anything and does not require you to do
44	anything special apart from loading it I<before doing any non-blocking	48	anything special apart from loading it I<before doing any non-blocking
45	requests with Net::SNMP>. It is recommended but not required to load this	49	requests with Net::SNMP>. It is recommended but not required to load this
46	module before C<Net::SNMP>.	50	module before C<Net::SNMP>.
…		…
65	case, this can lead to packet loss, when the receive queue overflows and	69	case, this can lead to packet loss, when the receive queue overflows and
66	the kernel can no longer accept new packets.	70	the kernel can no longer accept new packets.
67		71
68	To avoid this, you can (and should) limit the number of outstanding	72	To avoid this, you can (and should) limit the number of outstanding
69	requests to a number low enough so that parsing time doesn't introduce	73	requests to a number low enough so that parsing time doesn't introduce
70	noticable delays.	74	noticeable delays.
71		75
72	Unfortunately, this number depends not only on processing speed and load	76	Unfortunately, this number depends not only on processing speed and load
73	of the machine running Net::SNMP, but also on the network latency and the	77	of the machine running Net::SNMP, but also on the network latency and the
74	speed of your SNMP agents.	78	speed of your SNMP agents.
75		79
76	AnyEvent::SNMP tries to dynamically adjust this number dynamically upwards	80	AnyEvent::SNMP tries to dynamically adjust this number upwards and
77	and downwards.	81	downwards.
78		82
79	Increasing C<$MAX_OUTSTANDING> will not automatically use the	83	Increasing C<$MAX_OUTSTANDING> will not automatically use the
80	extra request slots. To increase C<$MAX_OUTSTANDING> and make	84	extra request slots. To increase C<$MAX_OUTSTANDING> and make
81	C<AnyEvent::SNMP> make use of the extra paralellity, call	85	C<AnyEvent::SNMP> make use of the extra parallelity, call
82	C<AnyEvent::SNMP::set_max_outstanding> with the new value, e.g.:	86	C<AnyEvent::SNMP::set_max_outstanding> with the new value, e.g.:
83		87
84	AnyEvent::SNMP::set_max_outstanding 500;	88	AnyEvent::SNMP::set_max_outstanding 500;
85		89
86	Although due to the dynamic adjustment, this might have little lasting	90	Although due to the dynamic adjustment, this might have little lasting
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99	When AnyEvent::SNMP handles $MAX_RECVQUEUE or more packets per iteration	103	When AnyEvent::SNMP handles $MAX_RECVQUEUE or more packets per iteration
100	it will reduce $MAX_OUTSTANDING. If it handles less than $MIN_RECVQUEUE,	104	it will reduce $MAX_OUTSTANDING. If it handles less than $MIN_RECVQUEUE,
101	it increases $MAX_OUTSTANDING.	105	it increases $MAX_OUTSTANDING.
102		106
103	This has the result of adjusting the number of outstanding requests so that	107	This has the result of adjusting the number of outstanding requests so that
104	the recv queue is between the minimum and maximu, usually.	108	the recv queue is between the minimum and maximum, usually.
105		109
106	This algorithm works reasonably well as long as the responses, response	110	This algorithm works reasonably well as long as the responses, response
107	latencies and processing times are the same size per packet on average.	111	latencies and processing times are the same per packet on average.
108		112
109	=back	113	=back
110		114
111	=head1 COMPATIBILITY	115	=head1 COMPATIBILITY
112		116
…		…
131		135
132	=cut	136	=cut
133		137
134	package AnyEvent::SNMP;	138	package AnyEvent::SNMP;
135		139
136	no warnings;	140	use common::sense;
137	use strict qw(subs vars);
138		141
139	# it is possible to do this without loading	142	# it is possible to do this without loading
140	# Net::SNMP::Dispatcher, but much more awkward.	143	# Net::SNMP::Dispatcher, but much more awkward.
141	use Net::SNMP::Dispatcher;	144	use Net::SNMP::Dispatcher;
142		145
		146	# we could inherit fro Net:SNMP::Dispatcher, but since this is undocumented,
		147	# I'd rather see it die (and reported) than silenty and subtly fail.
		148	*msg_handle_alloc = \&Net::SNMP::Dispatcher::msg_handle_alloc;
		149
143	sub Net::SNMP::Dispatcher::instance {	150	sub Net::SNMP::Dispatcher::instance {
144	AnyEvent::SNMP::	151	AnyEvent::SNMP::
145	}	152	}
146		153
147	use Net::SNMP ();	154	use Net::SNMP ();
148	use AnyEvent ();	155	use AnyEvent ();
149		156
150	our $VERSION = '1.0';	157	our $VERSION = '6.02';
151		158
152	$Net::SNMP::DISPATCHER = instance Net::SNMP::Dispatcher;	159	$Net::SNMP::DISPATCHER = instance Net::SNMP::Dispatcher;
153		160
154	our $MESSAGE_PROCESSING = $Net::SNMP::Dispatcher::MESSAGE_PROCESSING;	161	our $MESSAGE_PROCESSING = $Net::SNMP::Dispatcher::MESSAGE_PROCESSING;
155		162
…		…
250		257
251	# Set the error if applicable.	258	# Set the error if applicable.
252	$msg->error ($MESSAGE_PROCESSING->error) if $MESSAGE_PROCESSING->error;	259	$msg->error ($MESSAGE_PROCESSING->error) if $MESSAGE_PROCESSING->error;
253		260
254	# Notify the command generator to process the response.	261	# Notify the command generator to process the response.
255	$msg->process_response_pdu;	262	# Net::SNMP calls process_response_pdu, which simply calls callback_execute,
		263	# but some errors cause $msg to be of type Net::SNMP::Message, not Net::SMMP::PDU,
		264	# so we call the underlying callback_execute method which exists on both and
		265	# seems to do the right thing.
		266	$msg->callback_execute;
256		267
257	# Cancel the timeout.	268	# Cancel the timeout.
258	my $rtimeout_w = $msg->timeout_id;	269	my $rtimeout_w = $msg->timeout_id;
259	if ($$rtimeout_w) {	270	if ($$rtimeout_w) {
260	undef $$rtimeout_w;	271	undef $$rtimeout_w;
…		…
334	kick_job;	345	kick_job;
335		346
336	1	347	1
337	}	348	}
338		349
339	sub activate($) {	350	sub loop($) {
340	while ($BUSY) {	351	while ($BUSY) {
341	$DONE = AE::cv;	352	$DONE = AE::cv;
342	$DONE->recv;	353	$DONE->recv;
343	undef $DONE;	354	undef $DONE;
344	}	355	}
345	}	356	}
346		357
		358	*activate = \&loop; # 5.x compatibility?
		359	*listen = \&loop; # 5.x compatibility?
		360
347	sub one_event($) {	361	sub one_event($) {
348	# should not ever be used	362	# should not ever be used
349	AnyEvent->one_event; #d# todo	363	AnyEvent->one_event; #d# todo
350	}	364	}
351		365
352	sub set_max_outstanding($) {	366	sub set_max_outstanding($) {
353	$MAX_OUTSTANDING = $_[0];	367	$MAX_OUTSTANDING = $_[0];
354	kick_job;	368	kick_job;
355	}	369	}
356		370
		371	# not provided yet:
		372	# schedule # apparently only used by Net::SNMP::Dispatcher itself
		373	# register # apparently only used by Net::SNMP::Dispatcher itself
		374	# deregister # apparently only used by Net::SNMP::Dispatcher itself
		375	# cancel # apparently only used by Net::SNMP::Dispatcher itself
		376	# return_response_pdu # apparently not used at all?
		377	# error # only used by Net::SNMP::Dispatcher itself?
		378	# debug # only used by Net::SNMP::Dispatcher itself?
		379
357	=head1 SEE ALSO	380	=head1 SEE ALSO
358		381
359	L<AnyEvent>, L<Net::SNMP>, L<Net::SNMP::XS>, L<Net::SNMP::EV>.	382	L<AnyEvent>, L<Net::SNMP>, L<Net::SNMP::XS>, L<Net::SNMP::EV>.
360		383
361	=head1 AUTHOR	384	=head1 AUTHOR

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Comparing AnyEvent-SNMP/SNMP.pm (file contents): Revision 1.9 by root, Wed Jan 6 10:43:20 2010 UTC vs. Revision 1.14 by root, Wed Oct 9 18:22:59 2019 UTC

Diff Legend

Comparing AnyEvent-SNMP/SNMP.pm (file contents):
Revision 1.9 by root, Wed Jan 6 10:43:20 2010 UTC vs.
Revision 1.14 by root, Wed Oct 9 18:22:59 2019 UTC