I wanted to use a more OO approach to error handling in perl instead of just plain old eval, so I did some looking around. I wanted it to be easy, so I looked at these modules:

• Exception
• Error
• Exception::Class

I also found this article on perl exception handling: Object Oriented Exception Handling in Perl. That sounded great and all, but what would I be giving up?

I don’t know that much about perl internals, but I thought that code installed as a $SIG{__DIE__} signal handler would be faster than eval handling. I was wrong. Check this out:

I have these three small test scripts (indentation screwed up with the post):

eval.pl:

#!/usr/bin/perl -w
use strict;

use Benchmark qw(:all);;
use constant MAX => 150000;
my $code = sub {
  eval {
    die "this is an exception";
  };

  if($@)
  {
    #continue;
  }
  else
  {

  }
};

timethis(MAX, $code);

exception_class.pl:

#!/usr/bin/perl -w
use strict;

use Exception::Class ('TestException');
use Benchmark qw(:all);

use constant MAX => 150000;

my $code = sub {
  eval { TextException->throw(error => "this is an exception"); };
  if (UNIVERSAL::isa($@, 'TestException'))
  {
  }
};

timethis(MAX, $code);

error.pl:

#!/usr/bin/perl -w
use strict;`

use Error qw(:try);
use Benchmark qw(:all);;

use constant MAX => 150000;

my $code = sub {
  try {
    die "this is an exception";
  }
  catch Error with
  {
    #continue;
  }
  finally
  {

  };
};

timethis(MAX, $code);

exception.pl:

#!/usr/bin/perl -w
use strict;

use Exception qw(:all);
use Benchmark qw(:all);;

use constant MAX => 150000;

my $code = sub {
  try {
    die "this is an exception";
  }
  except
  {
    #continue;
  }
  finally
  {

  }
};

timethis(MAX, $code);

How did these compare in execution speed?

exception.pl:

23 wallclock secs (22.09 usr +  0.11 sys = 22.20 CPU) @ 6756.76/s (n=150000)

error.pl:

9 wallclock secs ( 7.90 usr +  0.02 sys =  7.92 CPU) @ 18939.39/s (n=150000)

exception_class.pl:

2 wallclock secs ( 1.37 usr +  0.00 sys =  1.37 CPU) @ 109489.05/s (n=150000)

eval.pl:

0 wallclock secs ( 0.41 usr +  0.00 sys =  0.41 CPU) @ 365853.66/s (n=150000)