> > The BARRIER thing might looks curious, but rdtsc has to be shielded
> > from the measured section, otherwise rdtsc's uops might mix up and
> > interact with the measured section - causing false results.
>
> IIRC, Intel recommends that a "CPUID" instruction should be used:
> it's a guaranteed serializing instruction.
yes, CPUID is serializing, but it interacts with the benchmarked section,
while the cli;lock;cli one i believe doesnt and is still serializing. Of
course this is only to ensure accurate benchmarking.
-- mingo
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