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]");
+ 
        }

[download]

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]"); 
        }

[download]
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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