[Twisted-Python] Seeking advice: Coping with heavy log file loads

[Marc Byrd]

Definitely use syslog.  To see how much logging is costing you without
changing code, you can simply route to /dev/null via syslog.  Btw, w/ local
logging, you may not see it in the cpu usage - more likely in the i/o wait.
 In my experience, logging to a remote syslog-ng server over udp has very
little impact on the app, almost like logging to /dev/null (which in turn is
like not logging at all).

Are you by chance on AWS/EC2 ?  If so, please contact me to discuss possible
design partnership.

m




On Fri, Apr 9, 2010 at 11:57 AM, Jason J. W. Williams <
jasonjwwilliams at gmail.com> wrote:

> Hi Paul,
>
> Is is sporadic? (the CPU burst) If so, you may be seeing the log
> rotation code kicking...and it's probably blocking your app too until
> it completes.
>
> I've got a couple patches to fix the blocking issue:
>
> http://twistedmatrix.com/trac/ticket/4372
>
> The patch which eliminates old log rotation will probably get rid of
> your CPU problem too.
>
> -J
>
> On Fri, Apr 9, 2010 at 2:35 AM, Paul Goins <general at vultaire.net> wrote:
> > There may not be a clear answer to this problem, and the answer may or
> > may not be Twisted-specific.  I'm just trying to fish for ideas here.
> >
> > The server I'm working on suffers from extremely high CPU time spent in
> > the logging functions.  I'm spending between 30 and 40% of all CPU time
> > just in twisted.python.log.msg.
> >
> > Describing the environment:
> >
> > We use DailyLogFiles for file rotation along with the
> > PythonLoggingObserver to allow for logLevel support.  (Of course, this
> > gives us significant overhead from Python's complex logging
> > architecture; maybe we should drop this...)
> >
> > On a 1000 request test of this server, we generate 58,274 calls to
> > t.p.log.msg.  There's room for cleanup, but there's lots of pressure to
> > keep many of the log calls we have for forensic purposes, so we can only
> > cut this back so far.
> >
> > Anyway, does anyone have any ideas for speedups?  Any stories from
> > experience especially?  Shots in the dark are welcome.  ;-)
> >
> > -
> > Paul Goins
> >
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>
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