Here's what I get with your code. I fed it /usr/share/dict/words.

             Rate  read_proc   for_proc while_proc
read_proc  2.21/s         --       -17%       -39%
for_proc   2.65/s        20%         --       -26%
while_proc 3.60/s        63%        36%         --
[download]

---
print map { my ($m)=1<<hex($_)&11?' ':'';
$m.=substr('AHJPacehklnorstu',hex($_),1) }
split //,'2fde0abe76c36c914586c';
[download]