From: Andi Kleen <ak@linux.intel.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "Yan, Zheng" <zheng.z.yan@intel.com>,
linux-kernel@vger.kernel.org, eranian@google.com
Subject: Re: [PATCH 1/6] perf, x86: Basic Haswell LBR call stack support
Date: Mon, 22 Oct 2012 06:45:05 -0700 [thread overview]
Message-ID: <20121022134505.GG2095@tassilo.jf.intel.com> (raw)
In-Reply-To: <1350902016.2768.85.camel@twins>
On Mon, Oct 22, 2012 at 12:33:36PM +0200, Peter Zijlstra wrote:
> On Mon, 2012-10-22 at 14:11 +0800, Yan, Zheng wrote:
> > + /* LBR callstack does not work well with FREEZE_LBRS_ON_PMI */
> > + if (!cpuc->lbr_sel || !(cpuc->lbr_sel->config & LBR_CALL_STACK))
> > + debugctl |= DEBUGCTLMSR_FREEZE_LBRS_ON_PMI;
>
> How useful it is without this? How many calls between PMI and us getting
> to intel_pmu_lbr_read()?
We use it only for ring 3. For ring 0 we assume frame pointer or
dwarf information.
So the CPL filter acts as the freeze.
-andi
--
ak@linux.intel.com -- Speaking for myself only
next prev parent reply other threads:[~2012-10-22 13:45 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-22 6:11 [PATCH 0/6] perf, x86: Haswell LBR call stack support Yan, Zheng
2012-10-22 6:11 ` [PATCH 1/6] perf, x86: Basic " Yan, Zheng
2012-10-22 10:33 ` Peter Zijlstra
2012-10-22 11:23 ` Stephane Eranian
2012-10-23 5:31 ` Yan, Zheng
2012-10-22 13:45 ` Andi Kleen [this message]
2012-10-23 5:28 ` Yan, Zheng
2012-10-22 10:35 ` Peter Zijlstra
2012-10-22 13:49 ` Andi Kleen
2012-10-23 5:41 ` Yan, Zheng
2012-10-23 10:11 ` Peter Zijlstra
2012-10-23 12:09 ` Stephane Eranian
2012-10-23 16:34 ` Andi Kleen
2012-10-22 6:11 ` [PATCH 2/6] perf, x86: Introduce x86 special perf event context Yan, Zheng
2012-10-22 6:11 ` [PATCH 3/6] perf, x86: Save/resotre LBR stack during context switch Yan, Zheng
2012-10-22 6:11 ` [PATCH 4/6] perf, core: Pass perf_sample_data to perf_callchain() Yan, Zheng
2012-10-22 6:11 ` [PATCH 5/6] perf, x86: Use LBR call stack to get user callchain Yan, Zheng
2012-10-22 6:11 ` [PATCH 6/6] perf, x86: Discard zero length call entries in LBR call stack Yan, Zheng
-- strict thread matches above, loose matches on Subject: below --
2012-10-22 5:57 [PATCH 0/6] perf, x86: Haswell LBR call stack support Yan, Zheng
2012-10-22 5:57 ` [PATCH 1/6] perf, x86: Basic " Yan, Zheng
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