Re: performance drop after using blkcg

From: Tejun Heo
Date: Tue Dec 11 2012 - 09:27:36 EST


On Tue, Dec 11, 2012 at 09:25:18AM -0500, Vivek Goyal wrote:
> In general, do not use blkcg on faster storage. In current form it
> is at best suitable for single rotational SATA/SAS disk. I have not
> been able to figure out how to provide fairness without group idling.

I think cfq is just the wrong approach for faster non-rotational
devices. We should be allocating iops instead of time slices.

Thanks.

--
tejun
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