Date: Wed, 2 Nov 2005 16:23:23 +0100 From: Bernd Walter <ticso@cicely12.cicely.de> To: Gavin Atkinson <gavin.atkinson@ury.york.ac.uk> Cc: freebsd-current@freebsd.org, rwatson@freebsd.org Subject: Re: Poor NFS server performance in 6.0 with SMP and mpsafenet=1 Message-ID: <20051102152322.GF93549@cicely12.cicely.de> In-Reply-To: <1130943516.51544.34.camel@buffy.york.ac.uk> References: <1130943516.51544.34.camel@buffy.york.ac.uk>
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On Wed, Nov 02, 2005 at 02:58:36PM +0000, Gavin Atkinson wrote: > Hi, > > I'm seeing incredibly poor performance when serving files from an SMP > FreeBSD 6.0RC1 server to a Solaris 10 client. I've done some > experimenting and have discovered that either removing SMP from the > kernel, or setting debug.mpsafenet=0 in loader.conf massively improves > the speed. Switching preemption off seems to also help. > > A quick summary of my findings: switching SMP off and setting > mpsafenet=0 gives more than 700% boost in performance. PREEMPTION is a > pessimisation in the SMP case, mpsafenet=1 is a pessimisation in all > cases. Given these are three of the major new features in 6.0, this > doesn't seem ideal :) > > The following are average times, in seconds, to serve a 512meg file over > NFS to the Solaris host. Each experiment was performed immediately > after a reboot of the FreeBSD host, and after one untimed transfer (in > order to warm the FreeBSD vfs cache). > > No SMP, mpsafenet=1 59.4 > No SMP, mpsafenet=0 49.4 > No SMP, mpsafenet=1, no PREEMPTION 53.1 > No SMP, mpsafenet=0, no PREEMPTION 51.9 > SMP, mpsafenet=1 351.7 > SMP, mpsafenet=0 74.5 > SMP, mpsafenet=1, no PREEMPTION 264.9 > SMP, mpsafenet=0, no PREEMPTION 53.7 Which scheduler? -- B.Walter BWCT http://www.bwct.de bernd@bwct.de info@bwct.de
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