Re: [PATCH v3 0/3] perf report/annotate: Support average IPC and IPC coverage for function

Jin, Yao
2018-11-28T12:39:28Z

On 11/28/2018 5:10 PM, Ingo Molnar wrote:
>
> * Jin Yao <yao.jin@linux.intel.com> wrote:
>
>> Add supporting of displaying the average IPC and IPC coverage
>> percentage per function.
>>
>> For example,
>>
>> $ perf record -b ...
>> $ perf report -s symbol or
>> perf report -s symbol --stdio
>>
>> Overhead Symbol IPC [IPC Coverage]
>> 39.60% [.] __random 2.30 [ 54.8%]
>> 18.02% [.] main 0.43 [ 54.3%]
>> 14.21% [.] compute_flag 2.29 [100.0%]
>> 14.16% [.] rand 0.36 [100.0%]
>> 7.06% [.] __random_r 2.57 [ 70.5%]
>> 6.85% [.] rand@plt 0.00 [ 0.0%]
>> ...
>>
>> $ perf annotate --stdio2
>>
>> Percent IPC Cycle (Average IPC: 2.30, IPC Coverage: 54.8%)
>>
>> Disassembly of section .text:
>>
>> 000000000003aac0 <random@@GLIBC_2.2.5>:
>> 8.32 3.28 sub $0x18,%rsp
>> 3.28 mov $0x1,%esi
>> 3.28 xor %eax,%eax
>> 3.28 cmpl $0x0,argp_program_version_hook@@GLIBC_2.2.5+0x1e0
>> 11.57 3.28 1 ↓ je 20
>> lock cmpxchg %esi,__abort_msg@@GLIBC_PRIVATE+0x8a0
>> ↓ jne 29
>> ↓ jmp 43
>> 11.57 1.10 20: cmpxchg %esi,__abort_msg@@GLIBC_PRIVATE+0x8a0
>
> That's a nice feature: please add meaningful documentation, accessible
> via the perf help system preferably, that outlines how the IPC metrics
> should be interpreted and how they are useful when optimizing programs.
>
> Thanks,
>
> Ingo
>

Hi Ingo,

Thanks so much for your comments! I think I will add some explanations
in perf/Documentation/perf-report.txt, maybe somewhere around the
sort_key section (-s::).

Thanks
Jin Yao