Re: Block IO Controller V4

From: Gui Jianfeng
Date: Tue Dec 01 2009 - 20:55:52 EST


Vivek Goyal wrote:
> Hi Jens,
>
> This is V4 of the Block IO controller patches on top of "for-2.6.33" branch
> of block tree.
>
> A consolidated patch can be found here:
>
> http://people.redhat.com/vgoyal/io-controller/blkio-controller/blkio-controller-v4.patch
>

Hi Vivek,

It seems this version doesn't work very well for "direct(O_DIRECT) sequence read" mode.
For example, you can create group A and group B, then assign weight 100 to group A and
weight 400 to group B, and you run "direct sequence read" workload in group A and B
simultaneously. Ideally, we should see 1:4 disk time differentiation for group A and B.
But actually, I see almost 1:2 disk time differentiation for group A and B. I'm looking
into this issue.
BTW, V3 works well for this case.

Thanks,
Gui

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