Developers of Sympa

[Olivier Salaün <address@concealed>]

We were reported some performance issues with the latest version of 
Sympa when running many K lists. We have investigated and we've 
optimized the code as described below. We've carried benchmarks on a 
server with 800 lists, mainly concentrating on optimizing the web 
interface responses. Therefore we've performed repeated requests while 
collecting profiling data. The procedure is described here : 
http://www.sympa.org/wiki/faq/performances. We've ended up reducing the 
processing time of 10 /sympa/home requests from 7.2 seconds to 2.9 
seconds. The optimizations mainly concerns pieces of the code that get 
called for each hosted list ; therefore the new code should help 
reducing the overhead for list services with a large number of lists.

List of the optimizations :

  1. reducing the do_log() calls thanks to an installation trick that
     makes do_log() calls conditional to the current log_level
  2. generalizing the use of List objects as parameters, thus reducing
     calls to List::new()
  3. limiting the use of file locking while checking list config files
     updates

(1) saved 3.7 sec during our tests
(2) + (3) saved 1.5 sec

We hope that some big sites will find some time to evaluate this new 
version of Sympa : http://www.sympa.org/distribution/sympa-5.4a.1.tar.gz
Please report us the results.

We'll now start another optimizing work. The goal is to reduce the 
memory usage of sympa processes.
Thanks to the feedback from Charles and Sergiy, it should not take too 
long before we get significant results.