Messages in this thread |  | | | Date | Mon, 16 Dec 2002 22:18:27 -0800 (PST) | | From | Linus Torvalds <> | | Subject | Re: Intel P6 vs P7 system call performance |
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On Mon, 16 Dec 2002, Linus Torvalds wrote: > > For gettimeofday(), the results on my P4 are: > > sysenter: 1280.425844 cycles > int/iret: 2415.698224 cycles > 1135.272380 cycles diff > factor 1.886637 > > ie sysenter makes that system call almost twice as fast.
Final comparison for the evening: a PIII looks very different, since the system call overhead is much smaller to begin with. On a PIII, the above ends up looking like
gettimeofday() testing: sysenter: 561.697236 cycles int/iret: 686.170463 cycles 124.473227 cycles diff factor 1.221602
ie the speedup is much less because the original int/iret numbers aren't nearly as embarrassing as the P4 ones. It's still a win, though.
Linus
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