Re^3: log4perl and efficiency

I don't think so, I mean in the first place I got rid of this interpolation problem by testing the log level using a call to Log4perl:

if ($self->{logger}->is_trace()) { # for efficiency (not to compute th
+e expression) 
            $self->{logger}->trace("total NbObsThis $i=$nbObservedThis
+NGram->[$i]; nbObsAll $i=$nbObservedAllNGrams->[$i]; total=$totalObse
+rvedAll; nbExpected $i=$nbExpectedThis[$i]; chisq = $chiSquare[$i]")
}
[download]

It helped indeed, but the cost of "is_trace()" was still prohibitive. Then I added a new variable $self->{disableLogger} set to true if the level is OFF (testing the log level only once) and replaced the condition with

if (!$self->{disableLogger} && $self->{logger}->is_trace()) { # test f
+or efficiency (not to compute the expression) {
            $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 this takes way less time (according to NYTProf). As previously said, it seems that a simple call to is_debug() (no interpolation) implies a complex (and long) computation in Log4perl.

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Re^4: log4perl and efficiency by ForgotPasswordAgain (Vicar) on Sep 12, 2011 at 22:20 UTC
Better yet, use a constant instead of a hashref lookup, and the whole if block will be obliterated at compile time when you disable debugging. `use constant DEBUG => 0; ... if (DEBUG) { # complex logging, which disappears from the op tree }` [download] FWIW, my experience has been like Solo's, where you end up inadvertently evaluating the arguments to the logging methods, and this takes a lot of time (or a little bit of time in a tight loop that's called a zillion times).	[reply] [d/l]

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Re^4: log4perl and efficiency
by ForgotPasswordAgain (Vicar) on Sep 12, 2011 at 22:20 UTC

Better yet, use a constant instead of a hashref lookup, and the whole if block will be obliterated at compile time when you disable debugging.

use constant DEBUG => 0;
...
if (DEBUG) {
    # complex logging, which disappears from the op tree
}
[download]

FWIW, my experience has been like Solo's, where you end up inadvertently evaluating the arguments to the logging methods, and this takes a lot of time (or a little bit of time in a tight loop that's called a zillion times).

[reply]
[d/l]