[syslog-ng] Profiling syslog-ng

[Roberto Nibali]

>> Increasing the time to 20000 usec cuts CPU in half again - to about 1/8 of
>> the original consumption. It's now using ~10-15% of a CPU under the same
>> heavy log load from ~750 connections. Granted, this increases latency, but I
>> don't think 10 or 20 msec delays will kill anything.
> 
> The idea is cool, although I have to admit it is really a hack :)

What's wrong/the issue with adding epoll? Besides non-portability? Also 
20msec may not hurt on 2.4.x kernels regarding latency however, 2.6.x 
kernels busy loop with HZ>100. Reducing HZ to something sensible like 
100 is better for servers anyway. Could the OP also put his .config 
online somewhere?

> This might be useful to others as well. I will probably add it as a
> global option. Thanks for tracking this down.

Could you please oprofile syslog-ng with your setup and configuration? 
Also, if you have some spare cycles to burn, have oprofile annotate your 
source with the profiler results. I happen to find oprofile a bit better 
to use for independent task/thread profiling sometimes than pure gprof. 
YMMV.

I don't have time right now, that's why I don't do it.

Regards,
Roberto Nibali, ratz
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