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SubjectRe: TPC-C benchmark used standard RH kernel
On Fri, Sep 20 2002, Mike Anderson wrote:
>
> 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.

They benched RHAS iirc, and that has the block-highmem patch. They also
had more than 4GB of memory, alas, there is bouncing. That doesn't work
on all hardware, and all drivers.

--
Jens Axboe

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