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How do I profile my Perl programs?


Jan 19, 2001, 11:52 AM

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How do I profile my Perl programs?

(From the Perl FAQ)

How do I profile my Perl programs?

You should get the Devel::DProf module from CPAN, and also use Benchmark.pm from the standard distribution. Benchmark lets you time specific portions of your code, while Devel::DProf gives detailed breakdowns of where your code spends its time.

Here's a sample use of Benchmark:

  use Benchmark; 

@junk = `cat /etc/motd`;
$count = 10_000;

timethese($count, {
'map' => sub { my @a = @junk;
map { s/a/b/ } @a;
return @a
'for' => sub { my @a = @junk;
local $_;
for (@a) { s/a/b/ };
return @a },

This is what it prints (on one machine--your results will be dependent on your hardware, operating system, and the load on your machine):

  Benchmark: timing 10000 iterations of for, map... 
for: 4 secs ( 3.97 usr 0.01 sys = 3.98 cpu)
map: 6 secs ( 4.97 usr 0.00 sys = 4.97 cpu)