linux-kernel - Re: perf with precise attribute kills all KVM based VMs

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Message-ID: <500BCD7A.4060108@redhat.com>
Date:	Sun, 22 Jul 2012 12:52:58 +0300
From:	Avi Kivity <avi@...hat.com>
To:	David Ahern <dsahern@...il.com>
CC:	Gleb Natapov <gleb@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: perf with precise attribute kills all KVM based VMs

On 07/21/2012 02:34 AM, David Ahern wrote:
> On 7/11/12 1:10 AM, Gleb Natapov wrote:
>> Looks like Avi is right about the overshoot. Can you test something
>> like this?
>>
>> diff --git a/arch/x86/kernel/cpu/perf_event_intel.c
>> b/arch/x86/kernel/cpu/perf_event_intel.c
>> index 166546e..5fb371a 100644
>> --- a/arch/x86/kernel/cpu/perf_event_intel.c
>> +++ b/arch/x86/kernel/cpu/perf_event_intel.c
>> @@ -1374,8 +1374,11 @@ static struct perf_guest_switch_msr
>> *intel_guest_get_msrs(int *nr)
>>       arr[0].msr = MSR_CORE_PERF_GLOBAL_CTRL;
>>       arr[0].host = x86_pmu.intel_ctrl & ~cpuc->intel_ctrl_guest_mask;
>>       arr[0].guest = x86_pmu.intel_ctrl & ~cpuc->intel_ctrl_host_mask;
>> +    arr[1].msr = MSR_IA32_PEBS_ENABLE;
>> +    arr[1].host = cpuc->pebs_enabled;
>> +    arr[1].guest = 0;
>> +    *nr = 2;
>>
>> -    *nr = 1;
>>       return arr;
>>   }
> 
> 
> Tested-by: David Ahern <dsahern@...il.com>

Thanks.

Gleb, please add a comment explaining about the skid, because otherwise
it looks redundant.


-- 
error compiling committee.c: too many arguments to function


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