Re: Putrid Elevator Behavior 2.4.18/19

Mike Fedyk
2002-03-20T22:01:56Z

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?