Re: xeon 2.8GHz SMP/NOT test results

On Mon, Oct 16, 2006 at 01:01:29PM +0200, Attilio Rao wrote:
> 2006/10/16, Ivan Voras <[email protected]>:
> >Kian Mohageri wrote:
> >
> >> I've never used sysbench (I essentially picked it randomly) so if you 
> >know
> >> it to be a crappy benchmark tool for this sort of thing, do tell.  I'm 
> >also
> >> pretty new at testing performance in general, but I hope someone finds it
> >> useful anyway.
> >
> >Maybe you'll be interested in ports/benchmark/unixbench, especially the
> >context switch and shell scripts benchmarks?
> >
> >> http://www.zampanosbits.com/smp_tests/
> >
> >Interesting results, especially for such an early version of the
> >processor (wrt HTT) - I'd expect much lower gain from HTT. While you're
> >at it, maybe you could add more results to your benchmark, like change
> >the timecounter to TSC, use various gcc optimization flags, twiddle
> >machdep.cpu_idle_hlt, use SMP kernel with HTT disabled in BIOS?
> 
> What about PREEMPTION/FULL_PREEMPTION?
> 
> Attilio
> 
> 
> -- 
> Peace can only be achieved by understanding - A. Einstein
> _______________________________________________

If the becnhmarks are being done to measure performance then
would not FULL_PREEMPTION be contra-indicated as it is a 
debugging option?

>From /usr/src/sys/conf/NOTES

# FULL_PREEMPTION instructs the kernel to preempt non-realtime kernel
#         threads.  Its sole use is to expose race conditions and other
#         bugs during development.  Enabling this option will reduce
#         performance and increase the frequency of kernel panics by
#         design.  If you aren't sure that you need it then you don't.
#         Relies on the PREEMPTION option.  DON'T TURN THIS ON.

Is there something happening I do not understand?

Most Respectfully,

Duane Whitty
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