Tuesday 2 October 2007

multicast_test: analyze mod_multicast performance

To measure mod_multicast computation consumption I developed a small Erlang module: multicast_test.

This module includes functions to create a message packet with an XEP33 'addresses' element. The number of destinations is configurable. And the server of each destination can be 'single', so all destinations are in the same server, or 'multiple', so each destination is from a different server. This packet can be sent to route_trusted or route_unstrusted. It is also possible to send individual packets to ejabberd_router.

Code profiling

It is possible to run those functions with Fprof to profile the time consumed by each function in mod_multicast:

fprof:apply(multicast_test, ROUTING, [SERVERS, NUM_DESTS]).
fprof:analyse([{dest, []}]).
  • ROUTING: testn for normal routing, testt for trusted sender, and testu for untrusted sender.
  • SERVERS: single for just a single server, multiple for a different server for each destination address.
  • NUM_DESTS: number of destination addresses.
For example, execute this in the Erlang shell of the ejabberd node:
fprof:apply(multicast_test, testu, [single, 300]).
fprof:analyse([{dest, []}]).
And you will get a file fprof.analysis with very detailed information.

Execution time

It's also possible to measure the execution time of those functions with a varying number of destinations. This will show if the performance of mod_multicast is dependant on the number of destinations or the number of destination servers...

The functions are:
multicast_test:ROUTING(SERVERS, INI, END, INC).
  • ROUTING: normal, trusted, untrusted.
  • SERVERS: single or multiple.
  • INI, END and INC: The initial number of destinations, the increment and the ending value.
For example:
multicast_test:untrusted(single, 1, 1000, 100).
I will later post some results I obtained using those functions.

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