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SubjectRe: gettimeofday() system call timing curiosity
Date
>
> > What happens if you remove the printf/puts and simply counts the number
> > of times the different cases happen?
> >
>
> Try it. It doesn't matter. Alan was correct, my computer sucks. However,
> they won't give me a 10 GHz one (yet). Note that although gettimeofday()
> has 1 microsecond resolution, not all the codes are exercised. We get
> something with the granularity of 50 to 190 microseconds.

I admit that I don't know the details of the x86 implementation,
but that sounds a little to large doesn't it?

I recently fixed the cris port to get 1 us resolution (by reading a
25MHz timer value within a jiffie).
My tests show that the time between calls to gettimeofday() typically
is 4-5 us on the 100MIPS ETRAX100LX - not that bad.
On my Linux PC i got 1us most of the time but never the same value,
but that is an old machine - PII 266 (reminds me I need to change machine:).

..
>
> Cheers,
> Dick Johnson

/Johan


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