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Hi all,

Facing some efficiency issues with a quite complex program, I used NYTProf to profile it. I noticed that the logging operations (using Log4perl) require a significant amount of time (about 25%), so I tried to disable logging by setting the log level to OFF. Nothing is logged (of course), but according to NYTProf the time taken by Log4perl is still the same. I thought that as soon as level was OFF calls to log4perl would have exited immediately, but it seems there are a lot of internal computations whatever the level (?).

I have already optimized the most frequent calls in the following way:

if ($self->{logger}->is_trace()) { $self->{logger}->trace("total NbObsThis $i=$nbObservedThis +NGram->[$i]; nbObsAll $i=$nbObservedAllNGrams->[$i]; total=$totalObse +rvedAll; nbExpected $i=$nbExpectedThis[$i]; chisq = $chiSquare[$i]"); + }

and I was very surprised when I saw that even this simple call to is_trace() (when the log level is OFF) is very costly (takes 30% of the time spent in a sub called very often).

Of course I can create my own condition like

if ($loggingOn) { $self->{logger}->trace("total NbObsThis $i=$nbObservedThisNGram->[$i]; + nbObsAll $i=$nbObservedAllNGrams->[$i]; total=$totalObservedAll; nbE +xpected $i=$nbExpectedThis[$i]; chisq = $chiSquare[$i]"); }
but it doesn't seem very elegant to add my own "optimized level" to the usual ones. Do you have any other ideas? Maybe something I missed about Log4perl?

Thank you!

In reply to log4perl and efficiency by erwan

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