Re: [PATCH] 2.6.0-test11 DAC960 request queue per disk

Andrew Morton
2003-12-15T22:03:47Z

Dave Olien <dmo@osdl.org> wrote:
>
>
> Here's a patch that changes the DAC960 driver from having one request
> queue for ALL disks on the controller, to having a request queue for
> each logical disk. This turns out to make little difference for deadline
> scheduler, nor for AS scheduler under light IO load. But under AS
> scheduler with heavy IO, it makes about a 40% difference on dbt2
> workload. Here are the measured numbers:
>
> The 2.6.0-test11-D kernel version includes this mutli-queue patch to the
> DAC960 driver.
>
> For non-cached dbt2 workload (heavy IO load)
>
> Scheduler kernel/driver NOTPM(bigger is better)
> AS 2.6.0-test11-D 1598
> AS 2.6.0-test11 973
> deadline 2.6.0-test11 1640
> deadline 2.6.0-test11-D 1645
>
> For cached dbt2 workload (lighter IO load)
>
> AS 2.6.0-test11-D 4993
> AS 2.6.-test6-mm4 4976, 4890, 4972
> deadline 2.6.0-test11-D 4998

Looks nice.

> Can this be included in 2.6.0? I know it's not a "critical patch"
> in the sense that something won't work without it. On the other hand,
> the change is isolated to a driver.

Let's queue it for 2.6.1 please. The default IO scheduler in 2.6.0 will
have some (known) efficiency problems anyway. (I thought those were fixed
in current -mm but we still seem to have tiobench randread problems).