Re: [PATCH] perf,x86: add constraint for IVB CYCLE_ACTIVITY:CYCLES_LDM_PENDING

[Stephane Eranian]

On Wed, Sep 11, 2013 at 6:50 PM, Andi Kleen <ak@xxxxxxxxxxxxxxx> wrote:
> On Wed, Sep 11, 2013 at 08:22:22AM -0700, Stephane Eranian wrote:
>>
>> The IvyBridge event CYCLE_ACTIVITY:CYCLES_LDM_PENDING can only
>> be measured on counters 0-3 when HT is off. When HT is on, you
>> only have counters 0-3.
>>
>> If you program it on the eight counters for 1s on a 3GHz
>> IVB laptop running a noploop, you see:
>>
>>            2 747 527 CYCLE_ACTIVITY:CYCLES_LDM_PENDING
>>            2 747 527 CYCLE_ACTIVITY:CYCLES_LDM_PENDING
>>            2 747 527 CYCLE_ACTIVITY:CYCLES_LDM_PENDING
>>            2 747 527 CYCLE_ACTIVITY:CYCLES_LDM_PENDING
>>        3 280 563 608 CYCLE_ACTIVITY:CYCLES_LDM_PENDING
>>        3 280 563 608 CYCLE_ACTIVITY:CYCLES_LDM_PENDING
>>        3 280 563 608 CYCLE_ACTIVITY:CYCLES_LDM_PENDING
>>        3 280 563 608 CYCLE_ACTIVITY:CYCLES_LDM_PENDING
>>
>> Clearly the last 4 values are bogus.
>
> Thanks looks good.
>
> Likely need it on Haswell too?
>
Will check on that one later this week.
But I think you are right.

> -Andi
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