Re: 2.5.70-mm9

From: Mingming Cao (cmm@us.ibm.com)
Date: Wed Jun 18 2003 - 02:13:00 EST


On Sat, 2003-06-14 at 23:20, Andrew Morton wrote:
> Mingming Cao <cmm@us.ibm.com> wrote:
> >
> > On Sat, 2003-06-14 at 01:01, Andrew Morton wrote:
> >
> > > Was elevator=deadline observed to fail in earlier kernels? If not then it
> > > may be an anticipatory scheduler bug. It certainly had all the appearances
> > > of that.
> > Yes, with elevator=deadline the many fsx tests failed on 2.5.70-mm5.
> >
> > > So once you're really sure that elevator=deadline isn't going to fail,
> > > could you please test elevator=as?
> > >
> > Ok, the deadline test was run for 10 hours then I stopped it (for the
> > elevator=as test).
> >
> > But the test on elevator=as (2.5.70-mm9 kernel) still failed, same
> > problem. Some fsx tests are sleeping on io_schedule().
> >
> > Next I think I will re-run test on elevator=deadline for 24 hours, to
> > make sure the problem is really gone there. After that maybe try a
> > different Qlogic Driver, currently I am using the driver from Qlogic
> > company(QLA2XXX V8).
>
> Martin has just observed what appears to be the same failure on
> 2.5.71-mjb1, which is the deadline scheduler, using qlogicisp.
>
> Again, some IO appears to have been submitted but it never came back.
>
> It could be a bug in the requests queueing code somewhere, or in the device
> driver.
>
> So a good thing to do now would be to find the workload+IO
> scheduler+filesystem which triggers it most easily, and run that with a
> different device driver. The feral driver (drivers/scsi/isp/ in -mm)
> should be suitable for that test.
>
>
I re-run the many fsx tests with feral driver on 2.5.70mm9, ext3
fileystems, on deadline scheduler and as scheduler respectively. Both
tests passed. They were running for more than 24 hours without any
problems. So it could be a bug in the device driver that I used
before(QLA2xxx V8). Before the fsx tests failed on ext3 on either
deadline scheduler or as scheduler.

Thanks for your time and help on tracing down this problem. :)

Mingming

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