refer to https://github.com/ceph/ceph/pull/5013
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 _______________________________________________ ceph-users mailing list [email protected] http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
