> -----Original Message----- > From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of Blair Bethwaite > Sent: 03 May 2017 09:53 > To: Dan van der Ster <dan@xxxxxxxxxxxxxx> > Cc: ceph-users@xxxxxxxxxxxxxx > Subject: Re: Intel power tuning - 30% throughput performance increase > > On 3 May 2017 at 18:38, Dan van der Ster <dan@xxxxxxxxxxxxxx> wrote: > > Seems to work for me, or? > > Yeah now that I read the code more I see it is opening and manipulating /dev/cpu_dma_latency in response to that option, so the > TODO comment seems to be outdated. I verified tuned latency-performance _is_ doing this properly on our RHEL7.3 nodes (maybe I > first tested this on 7.2 or just missed something then). In any case, I think we're agreed that Ceph should recommend that profile. I did some testing on this last year, by forcing the C-state to C1 I found that small writes benefited the most. 4kb writes to a 3x replica pool went from about 2ms write latency down to about 600us. I also measured power usage of the server and the increase was only a couple of percent. Ideally, I hoping for the day when the Linux scheduler is power aware so it always assigns threads to cores already running in higher C-states, that way we will hopefully get the benefits of both worlds without having to force all cores to run at max. > > -- > Cheers, > ~Blairo > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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