Messages in this thread |  | | Date | Tue, 21 Oct 2014 15:03:20 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2 0/12] perf/x86: implement HT leak workaround for SNB/IVB/HSW |
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On Tue, Oct 21, 2014 at 02:28:06PM +0200, Stephane Eranian wrote: > Peter, > > On Tue, Oct 21, 2014 at 1:25 PM, Peter Zijlstra <peterz@infradead.org> wrote: > > > > > > lkml.kernel.org/r/CABPqkBRbst4sgpgE5O_VXt-CSC0VD=aP2KWA0e3Uy64tw7df3A@mail.gmail.com > > > > I missed that 3 lines if they were in here. > > > I did not put them in there because there is another problem. > If you partition the generic counters 2 and 2, then some CPUs will not > be able to measure some events. > Unfortunately, there is no way to partition the 4 counters such that > all the events can be measured by > each CPU. Some events or precise sampling requires counter 2 for > instance (like prec_dist). > That's why I did not put this fix in.
Ah, I wasn't thinking about a hard partition, just a limit on the number of exclusive counters any one CPU can claim such as to not starve. Or is that what you were talking about? I feel not being able to starve another CPU is more important than a better utilization bound for counter scheduling.
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