Re: Putrid Elevator Behavior 2.4.18/19

Jeff V. Merkey
2002-03-20T22:10:06Z

> > > Jens/Linux,
> > >
> > > The elevator code is malfunctioning in 2.4.18/19-pre when we start
> > > reaching the upward limits with multiple 3Ware adapters
> > > running together. We started seeing the problem when we went to
> > > 64 K aligned writes with sustained > 200 MB/S writes to
> > > multiple 3Ware adapters.
> > >
> > > We have verified that the 3Ware adapters are not holding the request
> > > off, but that one of the requests is getting severely starved and
> > > does not get posted to the 3Ware adapters until thousands of IOs
> > > have gone before it.
> > >
> >
> > This elevator starvation problem has been identified and a patch already
> > merged into 2.4.19-pre2.
> >
> > Can you verify the affects it produces for your workload?
>
> I will comply. I tested with pre-3 patches and still saw this problem??
> Let me go and check the patches I applied to verify, I may not have
> applied the correct patch.
>
> Jeff

I verified we were using a stock 2.4.18 kernel on the specific system
without the pre-3 patches installed. We have been testing with the
latest patches but not on this system. We will apply and retest and
I will verify.

Jeff

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