Date: Tue, 17 Oct 2006 01:36:05 -0300 From: Duane Whitty <duane@dwlabs.ca> To: Attilio Rao <attilio@freebsd.org> Cc: freebsd-smp@freebsd.org Subject: Re: xeon 2.8GHz SMP/NOT test results Message-ID: <20061017043605.GC20196@dwpc.dwlabs.ca> In-Reply-To: <3bbf2fe10610160401u72748b2fi919994fb18f422e5@mail.gmail.com> References: <fee88ee40610151610g4af70cbfi1b79ed256cc78995@mail.gmail.com> <egvn2j$fmv$1@sea.gmane.org> <3bbf2fe10610160401u72748b2fi919994fb18f422e5@mail.gmail.com>
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On Mon, Oct 16, 2006 at 01:01:29PM +0200, Attilio Rao wrote: > 2006/10/16, Ivan Voras <ivoras@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 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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