Re: [RFC PATCH 3/3 v2] perf: Update perf tool to monitor uncoreevents

From: Andi Kleen
Date: Sun Nov 21 2010 - 07:09:44 EST



>
> 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.

-Andi


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