Here is the benchmark that tests two things: buffered vs unbuffered code
and multi-statement print vs single statement print styles. Here are the
code and results:
use Symbol;
my $fh = gensym;
open $fh, ">/dev/null" or die;
use Benchmark;
sub multi_print{
print $fh "<HTML>";
print $fh "<HEAD>";
print $fh "<TITLE>";
print $fh "Test page";
print $fh "<TITLE>";
print $fh "</HEAD>";
print $fh "<BODY BGCOLOR=\"black\" TEXT=\"white\">";
print $fh "<H1>";
print $fh "Hello";
print $fh "</H1>";
print $fh "<A HREF=\"foo.html\">";
print $fh "foo";
print $fh "</A>";
print $fh "</BODY>";
print $fh "</HTML>";
}
sub single_print{
print $fh qq{<HTML>
<HEAD>
<TITLE>Test page<TITLE>
</HEAD>
<BODY BGCOLOR="black" TEXT="white">
<H1>
Hello
</H1>
<A HREF="foo.html">foo</A>
</BODY>
</HTML>
};
}
timethese
(500_000, {
multi_print_unbuffered => sub {local $| = 1; multi_print() ;},
multi_print_buffered => sub { multi_print() ;},
single_print_unbuffered => sub {local $| = 1; single_print();},
single_print_buffered => sub { single_print();},
});
Benchmark: timing 500000 iterations of multi_print_buffered,
multi_print_unbuffered, single_print_buffered, single_print_unbuffered...
multi_print_buffered: 13 wallclock secs (11.09 usr + 0.17 sys = 11.26
CPU)
multi_print_unbuffered: 18 wallclock secs (16.50 usr + 0.31 sys = 16.81
CPU)
single_print_buffered: 2 wallclock secs ( 2.83 usr + 0.06 sys = 2.89
CPU)
single_print_unbuffered: 8 wallclock secs ( 7.75 usr + 0.26 sys = 8.01
CPU)
But if I put:
timethese
(500_000, {
multi_print_unbuffered => sub {local $| = 1; multi_print() ;},
multi_print_buffered => sub {local $| = 0; multi_print() ;},
single_print_unbuffered => sub {local $| = 1; single_print();},
single_print_buffered => sub {local $| = 0; single_print();},
});
Benchmark: timing 500000 iterations of multi_print_buffered,
multi_print_unbuffered, single_print_buffered, single_print_unbuffered...
multi_print_buffered: 18 wallclock secs (15.79 usr + 0.65 sys = 16.44
CPU)
multi_print_unbuffered: 18 wallclock secs (16.57 usr + 0.37 sys = 16.94
CPU)
single_print_buffered: 7 wallclock secs ( 7.23 usr + 0.12 sys = 7.35
CPU)
single_print_unbuffered: 9 wallclock secs ( 7.57 usr + 0.32 sys = 7.89
CPU)
There is no difference between buffered and not buffered, it seems that
the localizing of $| is what makes the difference. The multi vs single
still holds.
But you don't modify $| unless you want to unbuffer, so the first test
seems to be fair to me. What do you think?
Do you think I should test it under Apache (thru ab) since it might behave
differently under Apache? But I doubt I'd be able to measure this unless
the text would be huge to get the real feel of the numbers. You saw that
I'd to run 500_000 tests to get some real numbers...
_____________________________________________________________________
Stas Bekman JAm_pH -- Just Another mod_perl Hacker
http://stason.org/ mod_perl Guide http://perl.apache.org/guide
mailto:[EMAIL PROTECTED] http://perl.org http://stason.org/TULARC
http://singlesheaven.com http://perlmonth.com http://sourcegarden.org
