One difficult part of benchmarking is keeping track of what you have changed, and what effect these changes had. Here is one way to do it:

First, isolate the part of your code that needs improvement in a subroutine. Then, create new subroutines with different names to try different approaches. Preserve the different implementations of the subroutine in the program. This ensures that you don't accidentally change something else in your code that ruins your comparison data. The Benchmark node mentioned above shows an example of this approach.

If you keep your subroutine short, it is easy for other people, such as Perl Monks, to help speed up your code.

It should work perfectly the first time! - toma

perldoc Benchmark
[download]

vi \perl\lib\Benchmark.pm
[download]

What you've written is a proper way of using benchmark. Ideally, you would insert several objects into your code to get the times you wanted, but you can do it in a clever and inobtrusive manner:

BEGIN {
   use Benchmark;
   my ($oldb, $newb);    # inside BEGIN for closure

   sub mybench {
      return unless ($opt_b);

      $newb = new Benchmark;
      if ($oldb) {       # i.e. don't run first time through
          print timediff($oldb, $newb);
      }
      $oldb = $newb;
   }
}

Getopt::Std;

getopts('b');

mybench();
# some code here
mybench();
# some more code here
mybench();
[download]

mycode.pl -b
[download]

perl -lne 'print unless /^\s*mybench();/' myscript.pl > production.pl
[download]

You don't trust it because it's simple?!

Well, I guess you still don't have that much experience, but here's a universal truth: the best code is usually the most simple. Usually.

Anyways, I don't know exactly how your program works, but I would first suggest to use you friend, Devel::Dprof.

( I'm not sure what you didn't understand about the output from Devel::Dprof, but it's pretty straight forward, I think.... It's just shows in order which subroutines were accessed most frequently )

Thanks for that information about benchmarking, that is exactly what I needed. Btw, what I meant by "I don't trust it because it is too simple" is that it looked like too simple of a solution to what looked to be a complex problem, but really wasn't.

For those who still want to see the code, here it is (I've removed all of the stuff that doesn't have to do with the hierarchy part, to cut down on confusion):

#!/usr/bin/perl

# ***********************
# Name: hierarchy.pl
# Author: Joe Ryan
# Date Finished: August 10th, 2001
# Where Used: http://amherst.k12.oh.us/cgi-bin/weblog/hierarchy.pl
# Description: An extension to mainlog.pl that lets the 
# user browse through the amherst website, showing the hits 
# per directory and per file. Note that the script
# doesn't directly run off the weblog, but rather a text 
# file that is created after processing the weblog.  

open(DATA,  'pagehits.txt');        
@mlines = <DATA>;        
close(DATA);
$cutat = 2;

# recursive function that prints the hierarchy
sub print_hierarchy
{
    my ($newlevelref, $newhitsref, $x, $stophere, $plvars, $temp, $tem
+p1, $resume) = @_;
    my (@newlevel) = @$newlevelref;
    my (@newhits) = @$newhitsref;

    if ($x<=$cutlevelat)
    {
        print  "<ul>\n";
        $spaces = "<li>";
        $spacesend = "</li>";
        my ($y)=0;
        for ($y=0; $y < @newlevel; $y++)
        {
            my ($newleveltemp) = $newlevel[$y];
            my ($newhitstemp) = $newhits[$y];
            my ($temp2) = $temp.$newleveltemp;
            my ($temp3) = $temp1.$newleveltemp;    
            my ($p_count) = ($newleveltemp =~ tr/\.//);
            if ($p_count < 1) {$temp2.="/"; $temp3.="/";}
            eval ("\$plvars1 = \$plvars\.\"&pathlevel".$x."=\$newlevel
+temp\"");
            print "$spaces $newhitstemp&nbsp;<a href=\"$temp2\">$newle
+veltemp</a>&nbsp;<a href=\"/cgi-bin/weblog/hierarchy.pl?&cutlevelat="
+.($x+1)."$plvars1\">></a>&nbsp;<a href=\"/cgi-bin/weblog/hierarchy.pl
+?addwatch=$temp3&addhits=$newhitstemp&cutlevelat=".($x+1)."$plvars\">
++</a>$spacesend\n" unless ($newleveltemp =~ /\./ || $newleveltemp eq 
+"");
            if ($y == $stophere)
            {
                eval ("print_hierarchy(\\\@newlevel".($x).", \\\@newhi
+ts".($x).", ".($x+1).", \$stophere".($x+1).", \$plvars1, \$temp2, \$t
+emp3, 1)");
            }
        }
        print  "$spaces<b>--------------</b>$spacesend\n";
        for ($y=0; $y < @newlevel; $y++)
        {
            my($newleveltemp) = $newlevel[$y];
            my($newhitstemp) = $newhits[$y];
            my($temp2) = $temp.$newleveltemp;
            my($temp3) = $temp1.$newleveltemp;
            eval ("\$plvars1 = \$plvars\.\"&pathlevel1=\$newleveltemp\
+"");
            my($p_count) = ($newleveltemp =~ tr/\.//);
            if ($p_count < 1) {$temp2.="/"; $temp3.="/";}
            print "$spaces $newhitstemp <a href=\"$temp2\">$newlevelte
+mp</a>"."&nbsp;<a href=\"/cgi-bin/weblog/hierarchy.pl?addwatch=$temp3
+&addhits=$newhitstemp&cutlevelat=0$plvars\">+</a>\n" if ($newleveltem
+p =~ /\./ && $newleveltemp ne "");
        }
        print  "</ul>\n";
    }
    else { return 1; }
}
use CGI;
$query = CGI::new();

# $cutlevelat is how many levels out a directory is from the base
$cutlevelat = $query->param("cutlevelat");
$cutlevelat=0 if (!$cutlevelat);

for ($i=0; $i<$cutlevelat; $i++)
{
    eval ("\$pathlevel".$i." = \$query->param(\"pathlevel".$i."\")");
}

print "Content-type: text/html\n\n<html><head><title>Hierarchy View</t
+itle></head><body bgcolor=\"#FFFFFF\">\n";

@mypath = ("");
@myhits = (0);
$y=0;
$v=0;
for ($i=0; $i<$cutlevelat; $i++)
{
    eval("\$n".$i."=0");
}

for($i=0; $i<@mlines; $i++)
{

    @entry = split (' ', $mlines[$i]);
    @path = split (/\//, $entry[0]);
    $temp="";
    $x=1;
    for (; $x<=$cutat;$x++)
    {
        $path1[$x-1]=$path[$x-1];
        $temp.=$path[$x-1];
        $temp.= "/";
    }
    $breakcheck=1;
    for ($c=0; $c<$cutlevelat; $c++)
    {
        $breakcheck=1;
        eval("\$pathlevel=\$pathlevel".$c);
        if ($path[$#path1+$c] eq $pathlevel)
        {
            eval("\$meep=\@newlevel".$c);
            for($z=0; $z<$meep; $z++)
            {
                eval ("\$narf=\$newlevel".$c."[\$z]");            
                if ($path[$#path1+1+$c] eq $narf)
                {        
                    eval ("\$newhits".$c."[\$z]+=\$entry[1]");
                    $breakcheck=0;
                }
            }
            if ($breakcheck)
            {
                eval("\$newlevel".$c."[\$n".$c."] = \$path[\$\#path1+1
++".$c."]");
                eval("\$newhits".$c."[\$n".$c."] = \$entry[1]");
                eval("\$n".$c."++");
            }
        }
    }    
    
    $entry[0]=$temp;
    $breakcheck=1;
    for($x=0; $x<@mypath; $x++)
    {
        if ($entry[0] eq $mypath[$x])
        {
            $myhits[$x]+=$entry[1];
            $breakcheck=0;
        }
    }
    if ($breakcheck)
    {
        $mypath[$t]=$entry[0];
        $myhits[$t]=$entry[1];    
        $t++;    
    }

}

@indices = (0 .. $#myhits);
@sorted_indices = sort {$myhits[$b] <=> $myhits[$a]} @indices;
@myhits = @myhits[@sorted_indices];
@mypath = @mypath[@sorted_indices];

for ($i=0; $i<$cutlevelat; $i++)
{
    eval("\@indices = (0 .. \$\#newhits".$i.")");
    eval("\@sorted_indices = sort {\$newhits".$i."[\$b] <=> \$newhits"
+.$i."[\$a]} \@indices");
    eval("\@newhits".$i." = \@newhits".$i."[\@sorted_indices]");
    eval("\@newlevel".$i." = \@newlevel".$i."[\@sorted_indices]");
}


# find where the next level of the hierarchy is supposed to go
for ($i=0; $i<$cutlevelat-1; $i++)
{
    eval ("\$stophere".($i+1)."=0");
    eval ("\$meep=\@newlevel".$i);
    eval ("\$pathlevel=\$pathlevel".($i+1));
    for ($x=0; $x<$meep; $x++)
    {
        eval ("\$narf=\$newlevel".($i)."[\$x]");
        if ($narf eq $pathlevel)
        {
            eval ("\$stophere".($i+1)."=\$x");
        }
    }
}

print "<h1>Individual Page Hits</h1>\n<table border=\"1\" cellpadding=
+\"5\">\n"; 

for($i=0; $i<@mypath; $i++)
{
    print "<tr><td>\n";
    my (@path) = split (/\//, $mypath[$i]);
    print $myhits[$i]."&nbsp;";
    print "<a href=\"http://www.amherst.k12.oh.us/\">Amherst Steele</a
+>";
    $temp = "http://www.amherst.k12.oh.us/";
    $temp1 = "/";
    if ($path[1] eq ""){$stop = 1;}
    $x=1;
    for ($x=1; $x < @path && $x < $cutat && $x != $stop; $x++)
    {
        print "&nbsp;>&nbsp;";
        $temp .= $path[$x];
        $temp1 .= $path[$x];
        $p_count = ($path[$x] =~ tr/\.//);
        if ($p_count < 1) {$temp.="/"; $temp1.="/";}
        print "<a href=\"".$temp."\">".$path[$x]."</a>";
    }
    $plvars = "&pathlevel0=$path[$#path]";
    $endpath = $path[$#path];
    if ($path[$#path] eq $pathlevel0)
    {
        print_hierarchy(\@newlevel0, \@newhits0, 1, $stophere1, $plvar
+s, $temp, $temp1, $resume);
    }
    $p_count = ($endpath =~ /\.//);
    if ($p_count < 1)
    {
        print "&nbsp;<a href=\"/cgi-bin/weblog/hierarchy.pl?&cutlevela
+t=1$plvars\">></a>&nbsp;";
    }
    $stop=0;
    print "&nbsp;<a href=\"/cgi-bin/weblog/hierarchy.pl?addwatch=$temp
+1&addhits=$myhits[$i]&cutat=$cutat\">+</a>";
    print "\n</td></tr>\n";
}
print "</table></body></html>";
[download]

I'm sure I can scope a lot of these variables a little better, and I'm sure that their are some more efficient ways to do some of the things I was doing (via a built-in function, etc.). If anyone sees anything at all to help sprouse it up, by all means tell me!