Date: Sat, 7 May 2005 00:59:27 +0200 From: Bernd Walter <ticso@cicely12.cicely.de> To: Kris Kennaway <kris@obsecurity.org> Cc: current@freebsd.org Subject: Re: Benchmarking mpsafevfs with parallel tarball extraction Message-ID: <20050506225926.GB75629@cicely12.cicely.de> In-Reply-To: <20050506200635.GB79102@xor.obsecurity.org> References: <20050506183529.GA46411@xor.obsecurity.org> <20050506184852.GA62656@xor.obsecurity.org> <20050506200635.GB79102@xor.obsecurity.org>
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On Fri, May 06, 2005 at 01:06:35PM -0700, Kris Kennaway wrote: > On Fri, May 06, 2005 at 11:48:52AM -0700, Kris Kennaway wrote: > > On Fri, May 06, 2005 at 11:35:29AM -0700, Kris Kennaway wrote: > > > > > I might be bumping into the bandwidth of md here - when I ran less > > > rigorous tests with lower concurrency of extractions I seemed to be > > > getting marginally better performance (about an effective concurrency > > > of 2.2 for both 3 and 10 simultaneous extractions - so at least it > > > doesn't seem to degrade badly). Or this might be reflecting VFS lock > > > contention (which there is certainly a lot of, according to mutex > > > profiling traces). > > > > I suspect that I am hitting the md bandwidth: > > > > # dd if=/dev/zero of=/dev/md0 bs=1024k count=500 > > 500+0 records in > > 500+0 records out > > 524288000 bytes transferred in 9.501760 secs (55177988 bytes/sec) Wasn't md's blocksize = systems's pagesize, IIRC 8k on sparc. I'm surprised that 1k even works. -- B.Walter BWCT http://www.bwct.de bernd@bwct.de info@bwct.de
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