Which version of perl are you using?

5.005_03 seems to have a really slow tr///, that actually is slower than s/// (singe celeron 466)

Benchmark: timing 250000 iterations of one, two...
       one:  1 wallclock secs ( 0.83 usr +  0.00 sys =  0.83 CPU)
       two:  1 wallclock secs ( 0.74 usr +  0.00 sys =  0.74 CPU)

Benchmark: timing 2000000 iterations of one, two...
       one:  7 wallclock secs ( 6.71 usr +  0.00 sys =  6.71 CPU)
       two:  6 wallclock secs ( 5.93 usr +  0.00 sys =  5.93 CPU)
[download]

However, 5.6.1 (on a dual p3 800) tr seems to be almost twice as fast.

Benchmark: timing 250000 iterations of one, two...
       one:  1 wallclock secs ( 0.26 usr +  0.00 sys =  0.26 CPU) @ 96
+1538.46/s (n=250000)
            (warning: too few iterations for a reliable count)
       two:  1 wallclock secs ( 0.46 usr +  0.00 sys =  0.46 CPU) @ 54
+3478.26/s (n=250000)

Benchmark: timing 2000000 iterations of one, two...
       one:  2 wallclock secs ( 2.06 usr +  0.00 sys =  2.06 CPU) @ 97
+0873.79/s (n=2000000)
       two:  4 wallclock secs ( 3.68 usr +  0.00 sys =  3.68 CPU) @ 54
+3478.26/s (n=2000000)
[download]

I don't know too much about the tr/// and s/// code, but it looks like someone went and optimized tr/// between 5.005 and 5.6.1. (Would someone who knows (japhy?) please comment on this?)