Messages in this thread | | | Date | Tue, 4 Jun 2013 20:03:37 -0700 | From | Tejun Heo <> | Subject | Re: [RFC v1] add new io-scheduler to use cgroup on high-speed device |
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(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.
* It definitely has to support hierarchy. Nothing which doesn't support full hierarchy can be added to cgroup at this point.
* 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.
Thanks.
-- tejun
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