purple:/tmp oneiros$ perl -version | head -2

This is perl, v5.8.6 built for darwin-thread-multi-2level
purple:/tmp oneiros$ perl timer.pl

100:
           Rate      map  new_map void_map      for  foreach
map      1089/s       --     -16%     -37%     -61%     -61%
new_map  1295/s      19%       --     -25%     -54%     -54%
void_map 1718/s      58%      33%       --     -38%     -39%
for      2793/s     156%     116%      63%       --      -1%
foreach  2825/s     159%     118%      64%       1%       --

500:
          Rate      map  new_map void_map  foreach      for
map      213/s       --     -14%     -35%     -60%     -60%
new_map  249/s      17%       --     -24%     -53%     -54%
void_map 328/s      54%      32%       --     -38%     -39%
foreach  526/s     147%     112%      61%       --      -2%
for      538/s     153%     116%      64%       2%       --

2500:
            Rate      map  new_map void_map      for  foreach
map       38.5/s       --     -15%     -38%     -61%     -61%
new_map   45.4/s      18%       --     -27%     -54%     -55%
void_map  61.9/s      61%      37%       --     -38%     -38%
for       99.5/s     158%     119%      61%       --      -0%
foreach  100.0/s     160%     120%      61%       0%       --