From: Andi Kleen <ak@linux.intel.com>
To: Stephane Eranian <eranian@google.com>
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
mingo@elte.hu, zheng.z.yan@intel.com
Subject: Re: [PATCH] perf/x86: fix uncore PCI fixed counter handling
Date: Tue, 10 Sep 2013 13:22:45 -0700 [thread overview]
Message-ID: <20130910202245.GF11427@tassilo.jf.intel.com> (raw)
In-Reply-To: <20130909195350.GA17643@google.com>
On Mon, Sep 09, 2013 at 12:53:50PM -0700, Stephane Eranian wrote:
>
> There was a bug in the handling of SNB-EP/IVB-EP uncore PCI
> fixed counters, e.g., IMC. It would cause erratic values to
> be returned for the IMC clockticks event. This was due to
> a bogus hwc->config value which was then written to PCI
> config space. The fixed counter has most fields marked as
> reserved with hw reset values of 0. Yet the kernel was
> defaulting to a hwc->config = ~0 and that was causing
> the issues. The patch sets the hwc->config values for fixed
> uncore event to 0. Now, the values of imc clockticks is
> correct.
>
> $ perf stat -a -C 0 -e uncore_imc_0/clockticks/ -I 1000 sleep 10
Looks good to me.
Reviewed-by: Andi Kleen <ak@linux.intel.com>
-Andi
next prev parent reply other threads:[~2013-09-10 20:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-09 19:53 [PATCH] perf/x86: fix uncore PCI fixed counter handling Stephane Eranian
2013-09-10 20:22 ` Andi Kleen [this message]
2013-09-12 11:11 ` [tip:perf/urgent] perf/x86: Fix " tip-bot for Stephane Eranian
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