It just came to my attention that Intel has advised Red Hat never to lock in C0 as it may affect the life expectancy of server components such as fans and the CPUs themselves.
FYI, YMMV. On Fri, May 19, 2017 at 5:53 PM, xiaoguang fan <[email protected]> wrote: > I have done a test about close c-stat , but performance didn't increase > > > > 2017-05-19 15:23 GMT+08:00 Xiaoxi Chen <[email protected]>: >> >> would be better to document it first on "Known system-wise tuning >> knobs" in the doc? >> >> >> 2017-05-05 8:28 GMT+08:00 Brad Hubbard <[email protected]>: >> > On Thu, May 4, 2017 at 10:58 AM, Haomai Wang <[email protected]> wrote: >> >> refer to https://github.com/ceph/ceph/pull/5013 >> > >> > How about we issue a warning about possible performance implications >> > if we detect this is not set to 1 *or* 0 at startup? >> > >> >> >> >> On Thu, May 4, 2017 at 7:56 AM, Brad Hubbard <[email protected]> >> >> wrote: >> >>> +ceph-devel to get input on whether we want/need to check the value of >> >>> /dev/cpu_dma_latency (platform dependant) at startup and issue a >> >>> warning, or whether documenting this would suffice? >> >>> >> >>> Any doc contribution would be welcomed. >> >>> >> >>> On Wed, May 3, 2017 at 7:18 PM, Blair Bethwaite >> >>> <[email protected]> wrote: >> >>>> On 3 May 2017 at 19:07, Dan van der Ster <[email protected]> wrote: >> >>>>> Whether cpu_dma_latency should be 0 or 1, I'm not sure yet. I assume >> >>>>> your 30% boost was when going from throughput-performance to >> >>>>> dma_latency=0, right? I'm trying to understand what is the >> >>>>> incremental >> >>>>> improvement from 1 to 0. >> >>>> >> >>>> Probably minimal given that represents a state transition latency >> >>>> taking only 1us. Presumably the main issue is when the CPU can drop >> >>>> into the lower states and the compounding impact of that over time. I >> >>>> will do some simple characterisation of that over the next couple of >> >>>> weeks and report back... >> >>>> >> >>>> -- >> >>>> Cheers, >> >>>> ~Blairo >> >>>> _______________________________________________ >> >>>> ceph-users mailing list >> >>>> [email protected] >> >>>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> >>> >> >>> >> >>> >> >>> -- >> >>> Cheers, >> >>> Brad >> >>> _______________________________________________ >> >>> ceph-users mailing list >> >>> [email protected] >> >>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> > >> > >> > >> > -- >> > Cheers, >> > Brad >> > -- >> > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >> > the body of a message to [email protected] >> > More majordomo info at http://vger.kernel.org/majordomo-info.html >> -- >> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >> the body of a message to [email protected] >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- Cheers, Brad _______________________________________________ ceph-users mailing list [email protected] http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
