Messages in this thread | | | Date | Sat, 13 Sep 2014 13:46:30 +0900 | From | Tejun Heo <> | Subject | Re: [PATCH RESEND 0/1] AHCI: Optimize interrupt processing |
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Hello,
On Thu, Sep 11, 2014 at 02:42:49PM +0200, Alexander Gordeev wrote: > As conversion of libata to blk mq has long done I tried the change
Hmmm? You mean scsi-mq?
> against the recent version and the results still appear worthwhile. > > The numbers are taken by running 'dd if=/dev/sd{a,b} of=/dev/null' > in parallel. All time values are in us. > > Before this update host lock average holdtime was 2.45 and > average waittime was 1.24. After the update average holdtime > dropped to 0.29 (about eight times) while average waittime > decreased to 0.58 (about two times). > > Also, port events are handled with local interrupts enabled > and compete on individual per-port locks with average holdtime > 1.25 and average waittime 1.48. So combined average holdtime > spent while holding host and port locks decreased from 2.45 to > 0.29 + 1.25 = 1.54 (about 1.6 times). > > The downside of this change is introduction of a kernel thread.
That shouldn't matter at all but can you please present the information in a more digestable form? e.g. CPU usage decreased from A to B when transferring N MB/s on certain setup.
Thanks.
-- tejun
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