Messages in this thread | | | Subject | Re: [RFC PATCH 3/3 v2] perf: Update perf tool to monitor uncore events | From | Peter Zijlstra <> | Date | Sun, 21 Nov 2010 18:45:29 +0100 |
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On Sun, 2010-11-21 at 13:22 +0100, Stephane Eranian wrote: > On Sun, Nov 21, 2010 at 1:09 PM, Andi Kleen <andi@firstfloor.org> wrote: > > > >> > >> samples pcnt function DSO > >> _______ _____ ______________________ > >> ____________________________________ > >> > >> 8.00 18.6% kallsyms_expand_symbol [kernel.kallsyms] > > > > Reporting a symbol for an uncore event seems highly misleading. > > After all the uncore counter has no idea for which core the event was, > > so there isn't really any instruction pointer to report. > > The event could be event caused by a PCI device or similar. > > > > For per function monitoring of uncore events one has to use > > OFFCORE_RESPONSE, like I implemented recently. > > > > I would suggest to not report any symbol names for uncore events. > > Doing so just will confuse users. > > > > In fact I suspect uncore events are only really useful > > with "stat", but not with "top", or if they are used in top > > then the symbol reporting should be disabled. > > > I agree, uncore should only be used for counting on a > per-cpu basis. You can leave the perf tool as is, but > that opens up the risk of misinterpretation by many users, > or you restrict this in the tool directly which is the better > solution in my mind.
I would argue against restricting the tool, print a warning perhaps. I mean, give the user all the rope he needs and tell him how to tie the knot is the unix way, right? :-)
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