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From: flee@shire.cs.psu.edu (Felix Lee)
Newsgroups: comp.lang.perl
Subject: Re: speed: V2 verses V3
Message-ID: <1989Dec18.112735.4443@psuvax1.cs.psu.edu>
Date: 18 Dec 89 11:27:35 GMT
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Tom Christiansen <tchrist@convex.COM> wrote:
> Anybody want to post a better benchmark?  I'm having trouble finding
> something that'll actually run for a long time.

You guys aren't really seriously into text processing, are you. :-)

Here's timings for a perl script that counts word frequencies.
	% time perl-2 wf.pl /etc/termcap >/dev/null
	13.3u + 0.9s = 0:15 (95%); (0k+864k)/92k (0+0)io (0f+80r)pg+0sw
	% !!
	13.4u + 0.7s = 0:14 (98%); (0k+872k)/92k (0+0)io (0f+79r)pg+0sw
	% !!
	13.3u + 0.8s = 0:14 (100%); (0k+872k)/92k (0+0)io (0f+79r)pg+0sw
	% time perl-3 wf.pl /etc/termcap >/dev/null
	18.6u + 1.0s = 0:20 (95%); (0k+944k)/84k (0+0)io (0f+73r)pg+0sw
	% !!
	18.7u + 0.9s = 0:20 (95%); (0k+944k)/84k (0+0)io (0f+72r)pg+0sw
	% !!
	18.7u + 0.9s = 0:20 (94%); (0k+944k)/84k (0+0)io (0f+73r)pg+0sw


This is on a Sun-4.  /etc/termcap is 146k, about 32000 total words,
about 2000 different words, average word length is 3 chars.

If you want worse behavior, try /usr/dict/words.  About 24000 words,
every one unique, average length 7 chars.  I get 103.0u for perl-2 and
158.2u for perl-3.

If you eliminate the simple arithmetic in the script, perl-3 performs
a little better, but still worse than perl-2.

Here's the script.

#!/usr/bin/perl
# Count word frequency.
while (<>) {
	foreach $k (split(/[^a-zA-Z]+/)) {
		$k =~ tr/A-Z/a-z/, ++$freq{$k} if ($k);
	}
}
foreach $k (sort downfreq keys(freq)) {
	printf "%5d %s\n", $freq{$k}, $k;
}
sub downfreq {
	($freq{$b} - $freq{$a}) || ($a gt $b);
}
--
Felix Lee	flee@shire.cs.psu.edu	*!psuvax1!flee