In message <20050506225926.GB75629_at_cicely12.cicely.de>, Bernd Walter writes: >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. That's only relevant for swap backed. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk_at_FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.Received on Sat May 07 2005 - 05:17:26 UTC
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