Re: TPC-C benchmark used standard RH kernel

Mike Anderson (andmike@us.ibm.com)
Fri, 20 Sep 2002 10:20:41 -0700


Dave Hansen [haveblue@us.ibm.com] wrote:
> Bond, Andrew wrote:
> > This isn't as recent as I would like, but it will give you an idea.
> > Top 75 from readprofile. This run was not using bigpages though.
> >
> > 00000000 total 7872 0.0066
> > c0105400 default_idle 1367 21.3594
> > c012ea20 find_vma_prev 462 2.2212

> > c0142840 create_bounce 378 1.1250
> > c0142540 bounce_end_io_read 332 0.9881

.. snip..
>
> Forgive my complete ignorane about TPC-C... Why do you have so much
> idle time? Are you I/O bound? (with that many disks, I sure hope not
> :) ) Or is it as simple as leaving profiling running for a bit before
> or after the benchmark was run?

The calls to create_bounce and bounce_end_io_read are indications that
some of your IO is being bounced and will not be running a peak
performance.

This is avoided by using the highmem IO changes which I believe are not
in the standard RH kernel. Unknown if that would address your idle time
question.

-andmike

-- 
Michael Anderson
andmike@us.ibm.com

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