Re: Benchmarking mpsafevfs with parallel tarball extraction

From: Kris Kennaway <kris_at_obsecurity.org>
Date: Fri, 6 May 2005 16:09:52 -0700
On Sat, May 07, 2005 at 12:59:27AM +0200, Bernd Walter wrote:
> 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.

1M block size, not 1K :)

Kris

Received on Fri May 06 2005 - 21:09:54 UTC

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