Thanks, I had mistyped my numbers (I was on a old 15" monitor where the font is set to like 3 pixels high and even 640x480 looked fuzzy, yeck).

Anyway, I noticed that there was some descripency between the relative speeds of regex versus split (that is, split used properly). And I wanted to see why, so first I added a few more tests: 

        Four  => sub { $testlarge =~ /([^\s]*)\s+/; my $y = $1; },
        Eight => sub { my $y = $testlarge =~ /(\S+)/; },
        Six   => sub { my ($y) =  split(/\s+/, $testlarge,2)    },
        Seven => sub { my ($y) =  split(/\s+/, $testlarge)      }

[download]
I noticed that your regex was different, so I wanted to see if was why things were slower (however, I didn't think so, since your's was simplier).

Running with string equal to "a " x 100 000 , I got these numbers: 

     Eight: 11 wallclock secs ( 4.68 usr +  5.46 sys = 10.14 CPU) @ 45
+0.69/s (n=4570)
      Four: 10 wallclock secs ( 4.79 usr +  5.21 sys = 10.00 CPU) @ 44
+9.60/s (n=4496)
     Seven: 10 wallclock secs ( 7.28 usr +  2.84 sys = 10.12 CPU) @ 29
+3.97/s (n=2975)
       Six: 10 wallclock secs ( 7.13 usr +  2.88 sys = 10.01 CPU) @ 29
+3.81/s (n=2941)

[download]
Which were (despite using the same regex) were still 50% faster than split, rather than being 40% slower.
Next I reduced the size of my string to: "a " x 100 . Here I got these numbers: 
     Eight: 12 wallclock secs (10.00 usr +  0.00 sys = 10.00 CPU) @ 13
+0970.90/s (n=1309709)
      Four: 11 wallclock secs (10.39 usr +  0.00 sys = 10.39 CPU) @ 88
+839.36/s (n=923041)
     Seven: 10 wallclock secs (10.49 usr +  0.00 sys = 10.49 CPU) @ 12
+2499.33/s (n=1285018)
       Six: 10 wallclock secs (10.54 usr +  0.00 sys = 10.54 CPU) @ 12
+1918.22/s (n=1285018)

[download]
Now the regex code (yours) leads by less than 10%, and my regex trails by a good 30%. So, I guess the conclusion is that regex preforms better than split on large scalars? I don't feel like mucking in the perl source code right now, so my guess as to why this is, has nothing to do with the way regex's or splits actually process the data, but rather that split is probably receiving a copy of the data, whereas regex is receiving a reference.

Cheers,
Gryn

In reply to More benchmarks and stuff by gryng
in thread is split optimized? by Anonymous Monk

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