Jeremy Hylton wrote:

If you are benchmarking various opcode effects, I'd recommend trying to revive the simple cycle counter instrumentation I did for Python 2.2. The idea is to use the Pentium cycle counter to measure the number of cycles spent on each trip through the mainloop.

For Linux >= 2.4 and an x86 CPU, oprofile will tell you (stochastically) how many CPU cycles are spent on each x86 instruction. http://oprofile.sourceforge.net/