Re: [PATCH 6/9] perf report: Support instruction latency

Liang, Kan
2021-02-05T16:10:01Z

On 2/5/2021 6:08 AM, Namhyung Kim wrote:
> On Wed, Feb 3, 2021 at 5:14 AM <kan.liang@linux.intel.com> wrote:
>>
>> From: Kan Liang <kan.liang@linux.intel.com>
>>
>> The instruction latency information can be recorded on some platforms,
>> e.g., the Intel Sapphire Rapids server. With both memory latency
>> (weight) and the new instruction latency information, users can easily
>> locate the expensive load instructions, and also understand the time
>> spent in different stages. The users can optimize their applications
>> in different pipeline stages.
>>
>> The 'weight' field is shared among different architectures. Reusing the
>> 'weight' field may impacts other architectures. Add a new field to store
>> the instruction latency.
>>
>> Like the 'weight' support, introduce a 'ins_lat' for the global
>> instruction latency, and a 'local_ins_lat' for the local instruction
>> latency version.
>
> Could you please clarify the difference between the global latency
> and the local latency?
>

The global means the total latency.
The local means average latency, aka total / number of samples.

Thanks,
Kan