Re: CFQ idling kills I/O performance on ext4 with blkio cgroup controller
From: Jan Kara
Date: Wed Jun 12 2019 - 09:09:25 EST
On Tue 11-06-19 15:34:48, Srivatsa S. Bhat wrote:
> 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 ;
> >> b) 500-1000% higher throughput in multi-client server workloads, as I
> >> already pointed out .
> > 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,
> Hope you are doing great!
> I was wondering if you got a chance to post these patches to LKML for
> review and inclusion... (No hurry, of course!)
> 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?
Since CFQ doesn't exist in current upstream kernel anymore, I seriously
doubt you'll be able to get any performance improvements for it in the
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR