dpuu has asked for the wisdom of the Perl Monks concerning the following question:

Is there a standard way to find out how much memory a perl process is using? On a Linux box, I'm currently using: 
sub get_memory_used
{
  my $result;
  open STAT, "</proc/$$/status" or die "can't open ...: $!";
  while (<STAT>)
  {
    /^VmSize.*?(\d+) kB/ or next;
    $result = $1;
    last;
  }
  close STAT;
  defined($result) or die "can't find memory used";
  return $result * 1024;
}

[download]
but this doesn't feel very portable. --Dave

Replies are listed 'Best First'.
Re: get memory usage
by Zaxo (Archbishop) on Aug 24, 2002 at 00:33 UTC

    If perl is compiled with DEBUGGING_MSTATS set, Devel::Peek::mstat("Some Tag") will dump memory stats.

    After Compline,
    Zaxo

[reply]
Re: get memory usage
by RMGir (Prior) on Aug 24, 2002 at 00:30 UTC
    It's not a very portable problem, unfortunately.

    Check out Proc::ProcessTable; it will give you memory usage for different platforms. But even with that, the key for memory usage changes on many oses.

    Your best bet is probably using /proc, as you are now; that's fairly portable these days, at least on Unices. Not MacOSX, though. (Edit: As sauoq points out below, proc's internals aren't portable, though.)

    For an example of using proc on another OS, check out Solaris::ProcFS.
    --
    Mike

[reply]
      Your best bet is probably using /proc, as you are now; that's fairly portable these days, at least on Unices.

      Unfortunately, that just isn't true. Even among systems that have /proc, the format is often very different.

      -sauoq
"My two cents aren't worth a dime.";
[reply]
Re: get memory usage
by perrin (Chancellor) on Aug 24, 2002 at 06:08 UTC
    Take a look at how Apache::SizeLimit and Apache::GTopLimit do it.
[reply]
      hehe looks like they ran into the same issue... (code from Apache::SizeLimit)
      BEGIN {
    # decide at compile time how to check for a process' memory size.
    if (($Config{'osname'} eq 'solaris') &&
     ($Config{'osvers'} >= 2.6)) {
    $HOW_BIG_IS_IT = \&solaris_2_6_size_check;
    } elsif ($Config{'osname'} eq 'linux') {
    $HOW_BIG_IS_IT = \&linux_size_check;
    } elsif ($Config{'osname'} =~ /(bsd|aix)/i) {
    # will getrusage work on all BSDs?  I should hope so.
    if (eval("require BSD::Resource;")) {
        $HOW_BIG_IS_IT = \&bsd_size_check;
    } else {
        die "you must install BSD::Resource for Apache::SizeLimit to w
+ork on your platform.";
    }
    } else {
    die "Apache::SizeLimit not implemented on your platform.";
    }
}

      [download]


      -Waswas
[reply]
[d/l]
        Right. There's no portable way to do it. Apache::GTopLimit uses a library from the Gnome project to abstract it, but it's harder to install because of that.
[reply]
Re: get memory usage
by zentara (Cardinal) on Aug 25, 2002 at 17:45 UTC 
    This nifty little sub was posted awhile back on this subject
    #!/usr/bin/perl -w
use strict;
#by rob au 
print join("\n", &memusage), "\n";
exit 0;
#   memusage subroutine 
#   usage: memusage [processid] 
#   this subroutine takes only one parameter, the process id for 
#   which memory usage information is to be returned.  If 
#   undefined, the current process id is assumed. 
#   Returns array of two values, raw process memory size and 
#   percentage memory utilisation, in this order.  Returns 
#   undefined if these values cannot be determined. 

sub memusage {
use Proc::ProcessTable;
my @results;
my $pid = (defined($_[0])) ? $_[0] : $$;
my $proc = Proc::ProcessTable->new;
my %fields = map { $_ => 1 } $proc->fields;
return undef unless exists $fields{'pid'};
foreach (@{$proc->table}) {
if ($_->pid eq $pid) {
push (@results, $_->size) if exists $fields{'size'};
push (@results, $_->pctmem) if exists $fields{'pctmem'};
};
};
return @results;
}

    [download]
[reply]
[d/l]

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