Re: [PATCH v7 11/18] perf tools: add mem access sampling core support

From: Stephane Eranian
Date: Thu Mar 28 2013 - 11:15:57 EST


On Thu, Mar 28, 2013 at 4:12 PM, Arnaldo Carvalho de Melo
<acme@xxxxxxxxxx> wrote:
> Em Thu, Mar 28, 2013 at 12:00:18PM -0300, Arnaldo Carvalho de Melo escreveu:
>> Em Thu, Mar 28, 2013 at 03:24:30PM +0100, Stephane Eranian escreveu:
>> > On Wed, Mar 27, 2013 at 5:56 PM, Arnaldo Carvalho de Melo
>> > > Stephane, if you could give it a try again to see that the fixups I did
>> > > (documented in the commit logs, just before my Signed-off-by) are ok,
>> > > that would be good.
>>
>> > I tried on a few examples on both NHM (only loads, no TLB) and SNB
>> > and got the right answers for my tests, including data symbol resolution.
>>
>> > What we discussed with Jiri yesterday can be added later on.
>>
>> > Thanks for the integration work. Looks good to me.
>>
>> Humm, I just tried it with a simple:
>>
>> perf mem -t load rec
>>
>> And got an OOPS, trying again, and this machine was suspended, perhaps
>> perf/core doesn't have that PEBS fix, will check.
>
> Yeah, after a fresh reboot it doesn't OOPses, the fix:
>
> commit 1d9d8639c063caf6efc2447f5f26aa637f844ff6
> Author: Stephane Eranian <eranian@xxxxxxxxxx>
> Date: Fri Mar 15 14:26:07 2013 +0100
>
> perf,x86: fix kernel crash with PEBS/BTS after suspend/resume
>
Okay, so you too fell into that trap! I mean laptop guys, trying to save
battery, yet running perf, c'mon... ;->

> --------
>
> Isn't in perf/core, cool, before your test results I thougt I had messed
> up something :-)
>
yeah, closed your laptop lid.....
Should work better with the suspend/resume fix now, hopefully.
Of course, on SNB systems, you also need that firmware patch
to enable PEBS, IIRC.
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