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

[Jin, Yao]

On 11/28/2018 5:10 PM, Ingo Molnar wrote:
> * Jin Yao <yao.jin@xxxxxxxxxxxxxxx> 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      â je     20
> >                            lock   cmpxchg %esi,__abort_msg@@GLIBC_PRIVATE+0x8a0
> >                          â jne    29
> >                          â 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