From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [RFC PATCH 3/7] xen: psr: reserve an RMID for each core Date: Tue, 7 Apr 2015 09:57:56 -0400 Message-ID: <20150407135756.GC3592@l.oracle.com> References: <20150404020423.22875.23590.stgit@Solace.station> <20150404021441.22875.9924.stgit@Solace.station> <20150406135956.GE12596@l.oracle.com> <1428401960.5671.27.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1428401960.5671.27.camel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Dario Faggioli Cc: Wei Liu , Ian Campbell , Andrew Cooper , George Dunlap , "xen-devel@lists.xen.org" , "JBeulich@suse.com" , "chao.p.peng@linux.intel.com" List-Id: xen-devel@lists.xenproject.org On Tue, Apr 07, 2015 at 10:19:22AM +0000, Dario Faggioli wrote: > On Mon, 2015-04-06 at 09:59 -0400, Konrad Rzeszutek Wilk wrote: > > On Sat, Apr 04, 2015 at 04:14:41AM +0200, Dario Faggioli wrote: > > > > XXX Another idea I just have is to allow the user to > > > somehow specify a different 'granularity'. Something > > > like allowing 'percpu_cmt'|'percore_cmt'|'persocket_cmt' > > > with the following meaning: > > > + 'percpu_cmt': as in this patch > > > + 'percore_cmt': same RMID to hthreads of the same core > > > + 'persocket_cmt': same RMID to all cores of the same > > > socket. > > > > > > 'percore_cmt' would only allow gathering info on a > > > per-core basis... still better than nothing if we > > > do not have enough RMIDs for each pCPUs. > > > > Could we allocate nr_online_cpus() / nr_pmids() and have > > some CPUs share the same PMIDs? > > > Mmm... I hope we can (see the reply to Chao about the per-socketness > nature of the RMIDs). > > I'm not sure what you mean here, though. In the box I have at hand there > are 144 CPUs and 71 RMIDs. So, 144/71=2... maybe I'm missing something > of what you mean, how should I use these 2 RMIDs? The other way - so 2 CPUs use 1 RMID. > > If RMIDs actually are per-socket, extending the existing Xen support to > reflect that, and take advantage of it would help a lot already. In such > box, it would mean I could use RMIDs 1-36, on each socket, per per-CPU > monitoring, and still have 35 RMIDs free (which could be 35x4=140, > depending *how* we extend te support to match the per-socket nature of > RMIDs). > > Let's see if that is confirmed... Of course, I can book the box again > here and test it myself (and will do that, if necessary :-D). > > Thanks and Regards, > Dario