Re: Performance degradation with FFSB between 2.6.20 and 2.6.21-rc7

[Jens Axboe]

On Thu, Apr 19 2007, Valerie Clement wrote:
> Jens Axboe wrote:
> >On Thu, Apr 19 2007, Valerie Clement wrote:
> >>Jens Axboe wrote:
> >>>Please tell me how you are running ffsb, and also please include a
> >>>dmessg from a booted system.
> >>>
> >>Hi,
> >>our mails crossed! please see my response to Andrew.
> >>You could reproduce the problem with dd command as suggested, it's more 
> >>easy.
> >>I'm sending you the dmesg info. For my tests I used the scsci sdc device.
> >
> >Thanks, it does. Can you try one thing for me? If you run the test on
> >sdc, try doing:
> >
> ># echo 64 > /sys/block/sdc/queue/iosched/quantum
> >
> >and repeat the test.
> >
> 
> OK, that's done.
> 
> With the change of quantum, the throughput scores are now a little bit 
> better in 2.6.21 than in 2.6.20.

Wonderful, now try the patch I sent in the next mail and repeat the
test.

-- 
Jens Axboe

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