in reply to Algorithm Efficiency vs. Specialized Hardware?
I believe the original benchamrk code as posted is broken.
Thanks to Aighearach for questioning my earlier
results and leading me along this path.
And here is the code I used to run the test:
Consider this code:
The output from that:my $now = 8; my %url = ( monday => { @{[map(($_,1), (1..1000))]} } ); timethese(0, { Grep => 'Grep();', Grep2 => q{(sort grep {$_ <= $now} keys %{$url{"monday"}})[-1]; +}, Grep3 => sub{(sort grep {$_ <= $now} keys %{$url{"monday"}})[-1 +];} }); sub Grep{ $now = (sort grep {$_ <= $now} keys %{$url{'monday'}})[-1]; }
Benchmark: running Grep, Grep2, Grep3, each for at least 3 CPU seconds... Grep: 4 wallclock secs ( 3.00 usr + 0.02 sys = 3.02 CPU) @ 219.21/s (n=662) Grep2: 4 wallclock secs ( 3.14 usr + 0.01 sys = 3.15 CPU) @ 356475.56/s (n=1122898) Grep3: 4 wallclock secs ( 3.30 usr + 0.04 sys = 3.34 CPU) @ 213.47/s (n=713)shows that something is definitely up, the "inline sub" and "called sub" take the same time, but the "inline quoted" version is unbelievably faster. I think it has something to do with the inline quoted version not really working the way the original poster intended (I think its some sort of quoting/scoping problem, but I'm not sure exactly what).
I have rerun my benchmarks with all the routines as "inline subs" and the results follow:
dataset size | Grep | Max | Ternary |
---|---|---|---|
100 | 2440.20/s | 2511.96/s | 2495.22/s |
1000 | 207.32/s | 222.81/s | 216.31/s |
10000 | 15.31/s | 16.77/s | 16.61/s |
my %url; my $now = 8; my @size=(100,1000,10000); foreach(@size){ my $size=$_; print "size=$size\n"; %url = ( monday => { @{[map(($_,1), (1..$size))]} } ); timethese(0, { Grep => sub {(sort grep {$_ <= $now} keys %{$url{"mond +ay"}})[-1];}, Ternary => sub {($now < $_ && $_ < 8 ? $_ : $now) for key +s %{$url{"monday"}};}, Max => sub {foreach ( keys %{$url{"monday"}} ) { $now + = $_ if $_ > $now };} }); undef %url; }
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RE: Re: Algorithm Efficiency vs. Specialized Hardware?
by btrott (Parson) on Jun 21, 2000 at 00:15 UTC | |
SCOPING
by Aighearach (Initiate) on Jun 21, 2000 at 00:56 UTC |
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