linux-kernel - Re: [PATCH v4 4/4] perf report: Documentation average IPC and IPC coverage

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Date:   Fri, 30 Nov 2018 08:22:53 +0800
From:   "Jin, Yao" <yao.jin@...ux.intel.com>
To:     Ingo Molnar <mingo@...nel.org>
Cc:     acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
        mingo@...hat.com, alexander.shishkin@...ux.intel.com,
        Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
        kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v4 4/4] perf report: Documentation average IPC and IPC
 coverage



On 11/29/2018 9:27 PM, Ingo Molnar wrote:
> 
> * Jin Yao <yao.jin@...ux.intel.com> wrote:
> 
>> Add explanations for new columns "IPC" and "IPC coverage" in perf
>> documentation.
>>
>> Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>
>> ---
>>   tools/perf/Documentation/perf-report.txt | 8 ++++++++
>>   1 file changed, 8 insertions(+)
>>
>> diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
>> index 474a494..e5a32f3 100644
>> --- a/tools/perf/Documentation/perf-report.txt
>> +++ b/tools/perf/Documentation/perf-report.txt
>> @@ -126,6 +126,14 @@ OPTIONS
>>   	And default sort keys are changed to comm, dso_from, symbol_from, dso_to
>>   	and symbol_to, see '--branch-stack'.
>>   
>> +	When the sort key symbol is specified, columns "IPC" and "IPC Coverage"
>> +	are enabled automatically. Column "IPC" reports the average IPC per function
>> +	and column "IPC coverage" reports the percentage of instructions with
>> +	sampled IPC in this function. IPC means Instruction Per Cycle. If it's low,
>> +	it indicates there may be performance bottleneck when the function is
>> +	executed, such as, memory access bottleneck. If a function has high overhead
>> +	and low IPC, it's worth further analysis for performance optimization.
> 
> Thank you for adding this!
> 
> Just a few small nits:
> 
> s/may be performance bottleneck
>   /may be a performance bottleneck
> 
> s/such as, memory access bottleneck
>   /such as a memory access bottleneck
> 
> s/it's worth further analysis for performance optimization.
>   /it's worth further analyzing it to optimize its performance.
> 
> ?
> 
> Other than that:
> 
> Reviewed-by: Ingo Molnar <mingo@...nel.org>
> 
> 	Ingo
> 

Thanks Ingo!

I will add these fixes in v5.

Thanks
Jin Yao