linux-kernel - Re: [PATCH] perf pmu-events: Fix the missing "cpu_clk

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Date:   Tue, 30 Jul 2019 09:43:01 +0800
From:   "Jin, Yao" <yao.jin@...ux.intel.com>
To:     Andi Kleen <ak@...ux.intel.com>
Cc:     acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
        mingo@...hat.com, alexander.shishkin@...ux.intel.com,
        Linux-kernel@...r.kernel.org, kan.liang@...el.com,
        yao.jin@...el.com
Subject: Re: [PATCH] perf pmu-events: Fix the missing "cpu_clk_unhalted.core"



On 7/30/2019 2:16 AM, Andi Kleen wrote:
>> diff --git a/tools/perf/pmu-events/jevents.c b/tools/perf/pmu-events/jevents.c
>> index 1a91a197cafb..d413761621b0 100644
>> --- a/tools/perf/pmu-events/jevents.c
>> +++ b/tools/perf/pmu-events/jevents.c
>> @@ -453,6 +453,7 @@ static struct fixed {
>>   	{ "inst_retired.any_p", "event=0xc0" },
>>   	{ "cpu_clk_unhalted.ref", "event=0x0,umask=0x03" },
>>   	{ "cpu_clk_unhalted.thread", "event=0x3c" },
>> +	{ "cpu_clk_unhalted.core", "event=0x3c" },
> 
> Not sure this is correct for non Atom.
> 
> On Atom thread==core, but that is not true with SMT/HyperThreading.
> 
> The big cores currently don't have this event, so it would
> match incorrectly.
> 
> This has to be handled on the event list level, perhaps with
> some enhancements.
> 
> -Andi
> 

Hi Andi,

It is used to handle the fixed counter encodings between JSON and perf. 
If big cores don't have this event, nothing will be generated in perf list.

In big cores pipeline.json, there is only "CPU_CLK_UNHALTED.THREAD", and 
there is no "CPU_CLK_UNHALTED.CORE" defined. So at least for now, 
CPU_CLK_UNHALTED.CORE will not be generated for big core.

Thanks
Jin Yao