xeon 2.8GHz SMP/NOT test results
jhb at freebsd.org
Thu Oct 19 07:54:07 PDT 2006
On Tuesday 17 October 2006 00:36, Duane Whitty wrote:
> On Mon, Oct 16, 2006 at 01:01:29PM +0200, Attilio Rao wrote:
> > 2006/10/16, Ivan Voras <ivoras at fer.hr>:
> > >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
> > >> 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?
As it says, don't use it, just use 'PREEMPTION'.
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