[concurrency-interest] micro benchmark hell

studdugie studdugie at gmail.com
Tue Sep 19 10:07:05 EDT 2006


Thank you Kasper. It just clicked.

New rule! No coding past 2AM.

On 9/19/06, Kasper Nielsen <kav at it.edu> wrote:
>   > I'm running it on a 2 way Opterton w/ Linux kernel v2.6.17.11 w/ Sun
> > JVM 1.5.0_08.  The problem I'm having is if I execute it often enough
> > eventually "Sum" will be greater than "Total time elapsed". Which as
> > far as I'm concerned is supposed to be impossible.
> >
> > Now it could be that because it's 4:30 AM and my brain is fried I'm
> > overlooking the obvious but I doubt it.  Any feedback would be greatly
> > appreciated.
> >
> > Regards,
> >
> > Dane Foster
>
> Hi Dane,
>
> Lets say:
>
> Thread1-Thread8 uses 1 s each on Processor 1
> Thread9-Thread16 uses 1 s each on Processor 2
>
> That's 16 seconds in total. But only 8 seconds in wall clock time
> (excluding time spent on starting/joining threads)
>
> - Kasper
>
>
>


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