Re: [PATCH] cfq-iosched: allow groups preemption for sync-noidleworkloads

From: Vivek Goyal
Date: Thu Jun 23 2011 - 14:09:14 EST

On Thu, Jun 23, 2011 at 08:21:59PM +0400, Konstantin Khlebnikov wrote:
> commit v2.6.32-102-g8682e1f "blkio: Provide some isolation between groups" break
> fast switching between task and journal-thread for very common write-fsync workload.
> cfq wait idle slice at each cfqq switch, if this task is from non-root blkio cgroup.
> This patch move idling sync-noidle preempting check little bit upwards and update
> new service_tree->count check for case with two different groups.
> I do not quite understand what means these check for new_cfqq, but now it even works.
> Without patch I got 49 iops and with this patch 798, for this trivial fio script:

Which filesystem you are using for these tests?

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