Re: Putrid Elevator Behavior 2.4.18/19

Jeff V. Merkey
2002-03-20T22:05:16Z

On Wed, Mar 20, 2002 at 02:02:41PM -0800, Mike Fedyk wrote:
> On Wed, Mar 20, 2002 at 12:04:55PM -0700, Jeff V. Merkey wrote:
> >
> >
> >
> > 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