> -----Original Message----- > From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of John Spray > Sent: 06 September 2016 13:44 > To: Wido den Hollander <wido@xxxxxxxx> > Cc: ceph-users <ceph-users@xxxxxxxx> > Subject: Re: Single Threaded performance for Ceph MDS > > On Tue, Sep 6, 2016 at 1:12 PM, Wido den Hollander <wido@xxxxxxxx> wrote: > > Hi, > > > > Recent threads on on the ML revealed that the Ceph MDS can benefit from using a fast single threaded CPU. > > > > Some tasks inside the MDS are still single-threaded operations, so the faster the code executes the better. > > > > Keeping that in mind I started to look at some benchmarks: > > http://cpubenchmark.net/singleThread.html > > > > The fastest server CPU there is the "Intel Xeon E3-1281 v3 @ 3.70GHz". > > > > This is a 4-core CPU, however, it can only address 32GB of memory. Which is not much in most situations. The E3 v5's can address 64GB memory now, not sure if that's enough. I think the turbo will probably get you nearer 4Ghz if it's all single threaded. They make awesome OSD nodes btw. > > > > The "Intel Xeon E5-1650 v4 @ 3.60GHz" however would also be a good candidate. It can address up to 1.5TB of DDR4 memory. The 6- > cores should also be sufficient. > > > > Is this a good assumption to make? > > > > - E5-1650 v4 @ 3.60GHz > > - 256GB of memory > > - Disable all CPU powersaving (c-state to 0) I think the kernel sets the max c-state to 1 even if you set it to 0 to stop the CPU burning itself up. Also you probably want to pin the frequency at the max as well. > > > > Does this make any sense for a Ceph MDS? > > Recent testing saw creates peak at around 5000 ops/s on an E5-2650 (Ben England) and a similar number on E5-2680 (eBay). I don't > think anyone has tried with a higher clocked single socket CPU -- it's reasonable to expect some improvement, although it might not > be dramatic. I would love to see the results. > > John > > > > > Wido > > _______________________________________________ > > 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 _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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