Date: Sun, 06 Oct 2002 17:15:09 -0700 From: Terry Lambert <tlambert2@mindspring.com> To: Antony T Curtis <antony.t.curtis@ntlworld.com> Cc: Nate Lawson <nate@root.org>, David Francheski <davidf@caymas.com>, freebsd-arch@FreeBSD.ORG, freebsd-smp@FreeBSD.org Subject: Re: Running independent kernel instances on dual-Xeon/E7500 system Message-ID: <3DA0D20D.C47E4EF8@mindspring.com> References: <Pine.BSF.4.21.0210041721250.96201-100000@root.org> <3D9EB0A4.4CD09E20@mindspring.com> <3D9EF6E9.9040700@ntlworld.com>
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Nathan Hawkins wrote: > Each approach has advantages and disadvantages, depending on what you're > trying to accomplish. I think in this case, it's that benchmarked performance actually goes down in FreeBSD 4.6 when you run SMP, as opposed to running UP, and FreeBSD -current is even worse, even if you disable the debugging that's on by default. Tools like "netperf" aren't really capable of taking advantage of additional processors, but they are excellent at showing the incremental slowdown that results from lack of CPU affinity (if applicable), as well as any additional locking overhead (if applicable). Tools that run against web servers, where the web server has been written to run with multiple processes (or mutithreaded, if the threads system on the platform is SMP scalable) show less improvement than expected; e.g.: http://www.softwareqatest.com/qatweb1.html#LOAD ...but they will at least show some small improvement with SMP. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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