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From: "Yan, Zheng" <zheng.z.yan@intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org,
	eranian@google.com, andi@firstfloor.org
Subject: Re: [PATCH v2 4/7] perf, x86: Save/resotre LBR stack during context switch
Date: Thu, 04 Jul 2013 19:39:00 +0800	[thread overview]
Message-ID: <51D55ED4.5030405@intel.com> (raw)
In-Reply-To: <20130704095735.GL18898@dyad.programming.kicks-ass.net>

On 07/04/2013 05:57 PM, Peter Zijlstra wrote:
> On Mon, Jul 01, 2013 at 03:23:04PM +0800, Yan, Zheng wrote:
>> +++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
>> @@ -185,6 +185,13 @@ void intel_pmu_lbr_reset(void)
>>  		intel_pmu_lbr_reset_32();
>>  	else
>>  		intel_pmu_lbr_reset_64();
>> +
>> +	wrmsrl(x86_pmu.lbr_tos, 0);
>> +}
> 
> I double checked; my SDM Jun 2013, Vol 3C 35-93 very explicitly states that
> MSR_LASTBRANCH_TOS is a read-only MSR. And afaicr all previous times I checked
> this it did say this too.
> 

thank you for point out this. I will update the patch

Yan, Zheng

  reply	other threads:[~2013-07-04 11:39 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-01  7:23 [PATCH v2 0/7] perf, x86: Haswell LBR call stack support Yan, Zheng
2013-07-01  7:23 ` [PATCH v2 1/7] perf, x86: Reduce lbr_sel_map size Yan, Zheng
2013-07-01  7:23 ` [PATCH v2 2/7] perf, x86: Basic Haswell LBR call stack support Yan, Zheng
2013-07-01  7:23 ` [PATCH v2 3/7] perf, x86: Introduce x86 special perf event context Yan, Zheng
2013-07-04 12:41   ` Peter Zijlstra
2013-07-05  3:19     ` Yan, Zheng
2013-07-05 12:45       ` Peter Zijlstra
2013-07-08  8:51         ` Yan, Zheng
2013-07-01  7:23 ` [PATCH v2 4/7] perf, x86: Save/resotre LBR stack during context switch Yan, Zheng
2013-07-04  9:57   ` Peter Zijlstra
2013-07-04 11:39     ` Yan, Zheng [this message]
2013-07-04 13:44     ` Andi Kleen
2013-07-04 14:00       ` Peter Zijlstra
2013-07-10 17:57         ` Andi Kleen
2013-07-04 12:44   ` Peter Zijlstra
2013-07-04 12:45   ` Peter Zijlstra
2013-07-05  5:36     ` Yan, Zheng
2013-07-05  8:15       ` Peter Zijlstra
2013-07-05  8:51         ` Yan, Zheng
2013-07-05 12:31           ` Peter Zijlstra
2013-08-08  6:18             ` Yan, Zheng
2013-07-01  7:23 ` [PATCH v2 5/7] perf, core: Pass perf_sample_data to perf_callchain() Yan, Zheng
2013-07-01  7:23 ` [PATCH v2 6/7] perf, x86: Use LBR call stack to get user callchain Yan, Zheng
2013-07-01  7:23 ` [PATCH v2 7/7] perf, x86: Discard zero length call entries in LBR call stack Yan, Zheng
  -- strict thread matches above, loose matches on Subject: below --
2012-10-24  5:59 [PATCH V2 0/7] perf, x86: Haswell LBR call stack support Yan, Zheng
2012-10-24  5:59 ` [PATCH V2 4/7] perf, x86: Save/resotre LBR stack during context switch Yan, Zheng

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