Re: [PATCH 02/20] blkio: Change CFQ to use CFS like queue time stamps

From: Corrado Zoccolo
Date: Wed Nov 04 2009 - 16:18:26 EST

Hi Vivek,
On Wed, Nov 4, 2009 at 12:43 AM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> o Previously CFQ had one service tree where queues of all theree prio classes
> Âwere being queued. One side affect of this time stamping approach is that
> Ânow single tree approach might not work and we need to keep separate service
> Âtrees for three prio classes.
Single service tree is no longer true in cfq for-2.6.33.
Now we have a matrix of service trees, with first dimension being the
priority class, and second dimension being the workload type
(synchronous idle, synchronous no-idle, async).
You can have a look at the series: .
It may have other interesting influences on your work, as the idle
introduced at the end of the synchronous no-idle tree, that provides
fairness also for seeky or high-think-time queues.

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