Hi Gary, Yes, you have overlooked the fact that the Northbridge is shared between 8 cores in the Interlagos architecture. Moreover, according to BKDG, NB events should be measure only by one core in the set of cores that share it, which invalidates your approach.
-- Leonardo Leonardo On Fri, Mar 21, 2014 at 1:05 PM, Gary Mohr <gary.m...@bull.com> wrote: > Hi Stephane, Vince, > > When I look at the umasks provided with uncore cbox pmu's, I see these > entries: > > :tf=0 > thread id filter [0-1] > :cf=0 > core id filter [0-7] > > This suggests to me that we can filter cbox uncore events to only count for > one core on the socket (and even one hyperthread on that core). I know that > is not the same as a thread of execution. > > But if a person was to force their application to run on a specific core and > not allow any other jobs on that core. Then use these filters to only count > uncore cbox events from that core, would we be seeing counts related to just > that process ?? > > This is certainly not a general solution and it is limited to events in the > cbox pmu but it seems like it may be able to provide some information that is > loosely tied to a specific application. > > Have I overlooked something here that would invalidate this kind of test ?? > Gary > > > -----Original Message----- > From: Stephane Eranian [mailto:eran...@googlemail.com] > Sent: Friday, March 21, 2014 10:36 AM > To: Vince Weaver > Cc: perfmon2-devel > Subject: Re: [perfmon2] Counting NorthBridge events of a single process > > On Thu, Mar 20, 2014 at 10:24 PM, Vince Weaver <vincent.wea...@maine.edu> > wrote: >> On Thu, 20 Mar 2014, Martin Ichilevici de Oliveira wrote: >> >>> That program measures the counter for all processes, but I'm >>> interested in measuring it only for my program. Since the other >>> examples were not working (out of the box) with that event, I decided >>> to modify the perf_event_open() call, which was >>> >>> perf_event_open(&fds[i].hw, -1, 0, -1, 0); >> >> NorthBridge and Uncore counters are socket-wide. You cannot measure the >> values per-process or per-thread. This is a hardware limitation. >> > Well, this is really a kernel-imposed limitation for a good reason. > The counters live in the uncore which is shared by all cores and > thus are subject to requests coming from all programs running > on the processor socket. Therefore there is NO way to correlate > counts you get to your particular application. Thus uncore events > are not allowed in per-thread mode. > > > >> ------------------------------------------------------------------------------ >> Learn Graph Databases - Download FREE O'Reilly Book >> "Graph Databases" is the definitive new guide to graph databases and their >> applications. Written by three acclaimed leaders in the field, >> this first edition is now available. Download your free book today! >> http://p.sf.net/sfu/13534_NeoTech >> _______________________________________________ >> perfmon2-devel mailing list >> perfmon2-devel@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/perfmon2-devel > > ------------------------------------------------------------------------------ > Learn Graph Databases - Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases and their > applications. Written by three acclaimed leaders in the field, > this first edition is now available. Download your free book today! > http://p.sf.net/sfu/13534_NeoTech > _______________________________________________ > perfmon2-devel mailing list > perfmon2-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/perfmon2-devel > > ------------------------------------------------------------------------------ > Learn Graph Databases - Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases and their > applications. Written by three acclaimed leaders in the field, > this first edition is now available. Download your free book today! > http://p.sf.net/sfu/13534_NeoTech > _______________________________________________ > perfmon2-devel mailing list > perfmon2-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/perfmon2-devel ------------------------------------------------------------------------------ Learn Graph Databases - Download FREE O'Reilly Book "Graph Databases" is the definitive new guide to graph databases and their applications. Written by three acclaimed leaders in the field, this first edition is now available. Download your free book today! http://p.sf.net/sfu/13534_NeoTech _______________________________________________ perfmon2-devel mailing list perfmon2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
