Re: [RFC v1] add new io-scheduler to use cgroup on high-speed device

[sanbai <sanbai@taobao.com>]

On 2013年06月05日 11:03, Tejun Heo wrote:
> (cc'ing Kent.  Original posting at
>   http://thread.gmane.org/gmane.linux.kernel/1502484 )
>
> Hello,
>
> On Wed, Jun 05, 2013 at 10:09:31AM +0800, Robin Dong wrote:
>> We want to use blkio.cgroup on high-speed device (like fusionio) for our mysql clusters.
>> After testing different io-scheduler, we found that  cfq is too slow and deadline can't run on cgroup.
>> So we developed a new io-scheduler: tpps (Tiny Parallel Proportion Scheduler).It dispatch requests
>> only by using their individual weight and total weight (proportion) therefore it's simply and efficient.
>>
>> Test case: fusionio card, 4 cgroups, iodepth-512
> So, while I understand the intention behind it, I'm not sure a
> separate io-sched for this is what we want.  Kent and Jens have been
> thinking about this lately so they'll probably chime in.  From my POV,
> I see a few largish issues.
>
> * It has to be scalable with relatively large scale SMP / NUMA
>    configurations.  It better integrate with blk-mq support currently
>    being brewed.
Ok, I will go on to look Jens's blk-mq branch.

>
> * It definitely has to support hierarchy.  Nothing which doesn't
>    support full hierarchy can be added to cgroup at this point.
Thanks for your note, hierarchy supporting will be added in my next 
version patch.
>
> * We already have separate implementations in blk-throtl and
>    cfq-iosched.  Maybe it's too late and too different for cfq-iosched
>    given that it's primarily targeted at disks, but I wonder whether we
>    can make blk-throtl generic and scalable enough to cover all other
>    use cases.
I have the same feeling. Let's wait other person's response.
>
> Thanks.
>


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Robin Dong
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