--- cvsroot/AnyEvent-SNMP/README	2009/03/31 22:39:40	1.2
+++ cvsroot/AnyEvent-SNMP/README	2009/04/19 11:06:21	1.3
@@ -42,8 +42,72 @@
     requests with Net::SNMP*. It is recommended but not required to load
     this module before "Net::SNMP".
 
+GLOBAL VARIABLES
+    $AnyEvent::SNMP::MAX_OUTSTANDING (default: 50, dynamic)
+        Use this package variable to restrict the number of outstanding SNMP
+        requests at any point in time.
+
+        Net::SNMP is very fast at creating and sending SNMP requests, but
+        much slower at parsing (big, bulk) responses. This makes it easy to
+        request a lot of data that can take many seconds to parse.
+
+        In the best case, this can lead to unnecessary delays (and even
+        time-outs, as the data has been received but not yet processed) and
+        in the worst case, this can lead to packet loss, when the receive
+        queue overflows and the kernel can no longer accept new packets.
+
+        To avoid this, you can (and should) limit the number of outstanding
+        requests to a number low enough so that parsing time doesn't
+        introduce noticable delays.
+
+        Unfortunately, this number depends not only on processing speed and
+        load of the machine running Net::SNMP, but also on the network
+        latency and the speed of your SNMP agents.
+
+        AnyEvent::SNMP tries to dynamically adjust this number dynamically
+        upwards and downwards.
+
+        Note that you can use Net::SNMP::XS to speed up parsing of responses
+        considerably.
+
+    $AnyEvent::SNMP::MIN_RECVQUEUE (default: 4)
+    $AnyEvent::SNMP::MAX_RECVQUEUE (default: 64)
+        These values specify the minimum and maximum receive queue length
+        (in units of one response packet).
+
+        When AnyEvent::SNMP handles $MAX_RECVQUEUE or more packets per
+        iteration it will reduce $MAX_OUTSTANDING. If it handles less than
+        $MIN_RECVQUEUE, it increases $MAX_OUTSTANDING.
+
+        This has the result of adjusting the number of outstanding requests
+        so that the recv queue is between the minimum and maximu, usually.
+
+        This algorithm works reasonably well as long as the responses,
+        response latencies and processing times are the same size per packet
+        on average.
+
+COMPATIBILITY
+    This module may be used as a drop in replacement for the
+    Net::SNMP::Dispatcher in existing programs. You can still call
+    "snmp_dispatcher" to start the event-loop, but then you loose the
+    benefit of mixing Net::SNMP events with other events.
+
+       use AnyEvent::SNMP;
+       use Net::SNMP;
+
+       # just use Net::SNMP as before
+
+       # ... start non-blocking snmp request(s)...
+       Net::SNMP->session (
+             -hostname    => "127.0.0.1",
+             -community   => "public",
+             -nonblocking => 1,
+          )->get_request (-callback => sub { ... });
+
+       snmp_dispatcher;
+
 SEE ALSO
-    AnyEvent, Net::SNMP, Net::SNMP::EV.
+    AnyEvent, Net::SNMP, Net::SNMP::XS, Net::SNMP::EV.
 
 AUTHOR
      Marc Lehmann <schmorp@schmorp.de>