linux-kernel - Re: [PATCH v3] perf annotate: Add itrace options support

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Date:   Tue, 15 Jun 2021 12:04:47 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     Yang Jihong <yangjihong1@...wei.com>,
        Adrian Hunter <adrian.hunter@...el.com>
Cc:     peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
        mark.rutland@....com, alexander.shishkin@...ux.intel.com,
        jolsa@...hat.com, namhyung@...nel.org,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] perf annotate: Add itrace options support

Hi Jihong,

Loop in Adrain to be aware this AUX trace change.

On Tue, Jun 15, 2021 at 10:40:36AM +0800, Yang Jihong wrote:
> The "auxtrace_info" and "auxtrace" functions are not set in "tool" member of
> "annotate". As a result, perf annotate does not support parsing itrace data.
> 
> Before:
> 
>   # perf record -e arm_spe_0/branch_filter=1/ -a sleep 1
>   [ perf record: Woken up 9 times to write data ]
>   [ perf record: Captured and wrote 20.874 MB perf.data ]
>   # perf annotate --stdio
>   Error:
>   The perf.data data has no samples!
> 
> Solution:
> 1.Add itrace options in help,
> 2.Set hook functions of "auxtrace_info" and "auxtrace" in perf_tool.
> 
> After:
> 
>   # perf record --all-user -e arm_spe_0/branch_filter=1/ ls
>   Couldn't synthesize bpf events.
>   perf.data
>   [ perf record: Woken up 1 times to write data ]
>   [ perf record: Captured and wrote 0.010 MB perf.data ]
>   # perf annotate --stdio

>    Percent |      Source code & Disassembly of libc-2.28.so for branch-miss (1 samples, percent: local period)
>   ------------------------------------------------------------------------------------------------------------
>            :
>            :
>            :
>            :           Disassembly of section .text:
>            :
>            :           0000000000066180 <__getdelim@@GLIBC_2.17>:
>       0.00 :   66180:  stp     x29, x30, [sp, #-96]!
>       0.00 :   66184:  cmp     x0, #0x0
>       0.00 :   66188:  ccmp    x1, #0x0, #0x4, ne  // ne = any
>       0.00 :   6618c:  mov     x29, sp
>       0.00 :   66190:  stp     x24, x25, [sp, #56]
>       0.00 :   66194:  stp     x26, x27, [sp, #72]
>       0.00 :   66198:  str     x28, [sp, #88]
>       0.00 :   6619c:  b.eq    66450 <__getdelim@@GLIBC_2.17+0x2d0>  // b.none
>       0.00 :   661a0:  stp     x22, x23, [x29, #40]

[...]

Nitpick: the above example is not typical for annotation, since it
doesn't show any C source code with samples.  At my side, I tested this
patch and confirmed the patch works well with below commands:

  # gcc -ggdb -O0 -o task_migration task_migration.c
  # perf record -e cs_etm/@..._etr0/u --per-thread ./task_migration
  # perf annotate --itrace=i1000 --stdio

The complete annotation result can be reviewed at [1].

Thus for this patch:

Tested-by: Leo Yan <leo.yan@...aro.org>

[1] https://paste.ubuntu.com/p/pHz74MYRPJ/

[...]