Re: [PATCH 08/19] perf c2c: Shared data analyser

From: Don Zickus
Date: Mon Mar 03 2014 - 10:06:38 EST


On Fri, Feb 28, 2014 at 01:03:31PM -0800, Davidlohr Bueso wrote:
> On Fri, 2014-02-28 at 14:46 -0500, Don Zickus wrote:
> > On Fri, Feb 28, 2014 at 11:08:59AM -0800, Andi Kleen wrote:
> > > Don Zickus <dzickus@xxxxxxxxxx> writes:
> > > > +
> > > > +static const struct perf_evsel_str_handler handlers[] = {
> > > > + { "cpu/mem-loads,ldlat=30/pp", perf_c2c__process_load, },
> > > > + { "cpu/mem-stores/pp", perf_c2c__process_store, },
> > >
>
> Hmm I'm getting this when running a simple record command.
>
> invalid or unsupported event: 'cpu/mem-loads/pp'
>
> This only occurs with c2c, other subcommands work normally. It's as if
> it were an old kernel, but it's Linus' latest. Is this an issue with the
> patch or something I'm missing?
>
> Furthermore, I see:
> ls /sys/bus/event_source/devices/cpu/events
> branch-instructions branch-misses cache-misses cache-references cpu-cycles instructions mem-loads

Hmm, so based on Andi's reply, I am assuming you are running on a Westmere
(or Nehalem) due to the lack of mem-stores.

If you don't have mem-stores, this tool isn't going to work. The tool can
only detect contention when sampling reads _and_ writes to the same
addresses.

Cheers,
Don
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