linux-kernel - Re: [PATCH v4 2/2] perf report: Support interactive annotation of code without symbols

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Date:   Wed, 26 Feb 2020 16:38:10 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Jin Yao <yao.jin@...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, ak@...ux.intel.com,
        kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v4 2/2] perf report: Support interactive annotation of
 code without symbols

On Tue, Feb 25, 2020 at 01:14:38PM +0800, Jin Yao wrote:
> For perf report on stripped binaries it is currently impossible to do
> annotation. The annotation state is all tied to symbols, but there are
> either no symbols, or symbols are not covering all the code.
> 
> We should support the annotation functionality even without symbols.
> 
> This patch fakes a dummy symbol and the symbol name is the string of
> address. After that, we just follow current annotation working flow.
> 
> For example,
> 
> 1. perf report
> 
> Overhead  Command  Shared Object     Symbol
>   20.67%  div      libc-2.27.so      [.] __random_r
>   17.29%  div      libc-2.27.so      [.] __random
>   10.59%  div      div               [.] 0x0000000000000628
>    9.25%  div      div               [.] 0x0000000000000612
>    6.11%  div      div               [.] 0x0000000000000645
> 
> 2. Select the line of "10.59%  div      div               [.] 0x0000000000000628" and ENTER.
> 
> Annotate 0x0000000000000628
> Zoom into div thread
> Zoom into div DSO (use the 'k' hotkey to zoom directly into the kernel)
> Browse map details
> Run scripts for samples of symbol [0x0000000000000628]
> Run scripts for all samples
> Switch to another data file in PWD
> Exit
> 
> 3. Select the "Annotate 0x0000000000000628" and ENTER.
> 
> Percent│
>        │
>        │
>        │     Disassembly of section .text:
>        │
>        │     0000000000000628 <.text+0x68>:
>        │       divsd %xmm4,%xmm0
>        │       divsd %xmm3,%xmm1
>        │       movsd (%rsp),%xmm2
>        │       addsd %xmm1,%xmm0
>        │       addsd %xmm2,%xmm0
>        │       movsd %xmm0,(%rsp)
> 
> Now we can see the dump of object starting from 0x628.
> 
> We can also press hotkey 'a' on address in report view.
> For branch mode, we only support the annotation for
> "branch to" address.
> 
>  v4:
>  ---
>  1. Support the hotkey 'a'. When we press 'a' on address,
>     now it supports the annotation.

please move this to separate patch, AFAICS it's separate change
and was broken before your change

thanks,
jirka