Question

As I said, I want to record the max memory used during program run time.

Answer 1

Devel::Size only measures the memory size one at a time for one particular data structure to measure the total memory size of all data structure used in your script On Unix-like systems, Proc::ProcessTable provides a nice API for it:

Here is a simple script, comparing it with Devel::Size.

 #!/usr/bin/perl -w
use strict;
use Proc::ProcessTable;
use Devel::Size qw(size);


my @arr = ('A' .. 'M');
my $devel_size = size(\@arr);
print "With DEVEL::SIZE I'm $devel_size bytes big\n";


my $t = Proc::ProcessTable->new();

foreach my $p ( @{$t->table} ) {
    if($p->pid() == $$) {
    print "With Proc::ProcessTable I'm ", $p->size(), " bytes big.\n";
        last;
    }
}

It gives:

With DEVEL::SIZE I’m 104 bytes big.
With Proc::ProcessTable I’m 5357568 bytes big.

Note: source of Info: http://www.perlmonks.org/