Perl ABC

1. Perl
›
2. Module
›
3. here

Devel::DProf - Simple Profiler

You may not get the performance you want when you run the program. Finding out which part is the bottleneck is not easy. You can use a tool called a profiler to find out which process in your program is taking a long time. (Currently, it is better to use Devel::NYTProf.)

The standard module has a simple profiler, the Devel::DProf module , which you can take advantage of.

Creating a profile is easy. When the following command is executed, a file that outputs the profile information "tmon.out" is created in the current directory.

# Create profile information
perl -d: DProf target.pl

To display "tmon.out" in an easy-to-read format, execute the dprofpp command.

# Display profile in easy-to-read format
dprofpp

Then, it will be output in the following easy-to-read format.

# Profile
Total Elapsed Time = 1.171916 Seconds
  User + System Time = 1.171916 Seconds
Exclusive Times
# %Time ExclSec CumulS Calls sec/call Csec/c Name
 78.6 0.922 0.922 2 0.4610 0.4610 main::func2
 18.6 0.218 0.218 1 0.2180 0.2180 main::func1
 1.37 0.016 0.016 5 0.0032 0.0032 main::BEGIN
 0.00 - - 0.000 1 - -- strict::bits
 0.00 - - 0.000 2 - -- strict::import
 0.00 - - 0.000 2 - -- warnings::import

The meaning of each item is as follows. It is displayed from the top in the order of time.

The above result is the result in my environment when I run the script.

use strict;
use warnings;

func1 ();
func2 ();
func2 ();

sub func1 {
  my $i = 0;
  while ($i < 1000000) {
    $i++;
  }
}

sub func2 {
  my $i = 0;
  while ($i < 2000000) {
    $i++;
  }
}

The number is incremented using while statement.