Date: Thu, 19 Oct 2006 10:16:58 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-smp@freebsd.org Cc: Attilio Rao <attilio@freebsd.org>, Duane Whitty <duane@dwlabs.ca> Subject: Re: xeon 2.8GHz SMP/NOT test results Message-ID: <200610191016.59275.jhb@freebsd.org> In-Reply-To: <20061017043605.GC20196@dwpc.dwlabs.ca> References: <fee88ee40610151610g4af70cbfi1b79ed256cc78995@mail.gmail.com> <3bbf2fe10610160401u72748b2fi919994fb18f422e5@mail.gmail.com> <20061017043605.GC20196@dwpc.dwlabs.ca>
next in thread | previous in thread | raw e-mail | index | archive | help
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@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? As it says, don't use it, just use 'PREEMPTION'. -- John Baldwin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200610191016.59275.jhb>