Messages in this thread | | | From | Paolo Valente <> | Subject | Re: CFQ idling kills I/O performance on ext4 with blkio cgroup controller | Date | Thu, 13 Jun 2019 07:46:12 +0200 |
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> Il giorno 12 giu 2019, alle ore 00:34, Srivatsa S. Bhat <srivatsa@csail.mit.edu> ha scritto: > > On 6/2/19 12:04 AM, Srivatsa S. Bhat wrote: >> On 5/30/19 3:45 AM, Paolo Valente wrote: >>> > [...] >>> At any rate, since you pointed out that you are interested in >>> out-of-the-box performance, let me complete the context: in case >>> low_latency is left set, one gets, in return for this 12% loss, >>> a) at least 1000% higher responsiveness, e.g., 1000% lower start-up >>> times of applications under load [1]; >>> b) 500-1000% higher throughput in multi-client server workloads, as I >>> already pointed out [2]. >>> >> >> I'm very happy that you could solve the problem without having to >> compromise on any of the performance characteristics/features of BFQ! >> >> >>> I'm going to prepare complete patches. In addition, if ok for you, >>> I'll report these results on the bug you created. Then I guess we can >>> close it. >>> >> >> Sounds great! >> > > Hi Paolo, >
Hi
> Hope you are doing great! >
Sort of, thanks :)
> I was wondering if you got a chance to post these patches to LKML for > review and inclusion... (No hurry, of course!) >
I'm having troubles testing these new patches on 5.2-rc4. As it happened with the first release candidates for 5.1, the CPU of my test machine (Intel Core i7-2760QM@2.40GHz) is so slowed down that results are heavily distorted with every I/O scheduler.
Unfortunately, I'm not competent enough to spot the cause of this regression in a feasible amount of time. I hope it'll go away with next release candidates, or I'll test on 5.1.
> Also, since your fixes address the performance issues in BFQ, do you > have any thoughts on whether they can be adapted to CFQ as well, to > benefit the older stable kernels that still support CFQ? >
I have implanted my fixes on the existing throughput-boosting infrastructure of BFQ. CFQ doesn't have such an infrastructure.
If you need I/O control with older kernels, you may want to check my version of BFQ for legacy block, named bfq-sq and available in this repo: https://github.com/Algodev-github/bfq-mq/
I'm willing to provide you with any information or help if needed.
Thanks, Paolo
> Thank you! > > Regards, > Srivatsa > VMware Photon OS
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