Messages in this thread | | | Date | Fri, 08 Mar 2002 10:50:53 -0800 | From | "H. Peter Anvin" <> | Subject | Re: gettimeofday() system call timing curiosity |
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Jamie Lokier wrote:
> > On my laptop, the median of rdtsc+gettimeofday+rdtsc times is 470 cycles > for most runs of 1000, but is occasionally 453 cycles. >
What that indicates to me is that 1000 is way too small of a sample. You're only talking a difference of 17,000 cycles, which could -- especially with cache effects -- easily be the time spent in an interrupt handler.
-hpa
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