linux-kernel - Re: [PATCH] perf tests: Make leader sampling test work without branch event

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Message-ID: <8a89ba95-22cb-4e69-a776-3c927e80f5df@linux.intel.com>
Date: Mon, 23 Dec 2024 17:04:34 +0800
From: "Mi, Dapeng" <dapeng1.mi@...ux.intel.com>
To: Ian Rogers <irogers@...gle.com>,
 Arnaldo Carvalho de Melo <acme@...nel.org>,
 "Liang, Kan" <kan.liang@...ux.intel.com>,
 James Clark <james.clark@...aro.org>
Cc: linux-perf-users@...r.kernel.org, Peter Zijlstra <peterz@...radead.org>,
 Ingo Molnar <mingo@...hat.com>, Namhyung Kim <namhyung@...nel.org>,
 Mark Rutland <mark.rutland@....com>,
 Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
 Jiri Olsa <jolsa@...nel.org>, Adrian Hunter <adrian.hunter@...el.com>,
 Veronika Molnarova <vmolnaro@...hat.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] perf tests: Make leader sampling test work without branch
 event


On 12/21/2024 3:08 PM, Ian Rogers wrote:
> On Sat, Nov 16, 2024 at 11:28 AM Arnaldo Carvalho de Melo
> <acme@...nel.org> wrote:
>> On Fri, Nov 15, 2024 at 10:54:43AM -0800, Ian Rogers wrote:
>>> On Fri, Nov 15, 2024 at 8:16 AM James Clark <james.clark@...aro.org> wrote:
>>>> Arm a57 only has speculative branch events so this test fails there. The
>>>> test doesn't depend on branch instructions so change it to instructions
>>>> which is pretty much guaranteed to be everywhere. The
>>>> test_branch_counter() test above already tests for the existence of the
>>>> branches event and skips if its not present.
>>>>
>>>> Signed-off-by: James Clark <james.clark@...aro.org>
>>> Reviewed-by: Ian Rogers <irogers@...gle.com>
>> Thanks, applied to perf-tools-next,
> Rebasing on perf-tools-next I see this failing on my Intel Tigerlake
> laptop. An example script output for:
> ```
>  perf record -o "${perfdata}" -e "{instructions,instructions}:Su"
> ```
> is:
> ```
>             perf  352917 49604.160314:          3 instructions:
> 7f155caca323 [unknown]
> (/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
>             perf  352917 49604.160314:          3 instructions:
> 7f155caca323 [unknown]
> (/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
>             perf  352917 49604.160317:         18 instructions:
> 7f155cacaf3d _dl_start+0x3d
> (/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
>             perf  352917 49604.160317:         18 instructions:
> 7f155cacaf3d _dl_start+0x3d
> (/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
>             perf  352917 49604.160319:          3 instructions:
> 7f155cacaf44 _dl_start+0x44
> (/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
>             perf  352917 49604.160319:          3 instructions:
> 7f155cacaf44 _dl_start+0x44
> (/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
>             perf  352917 49604.161099:        120 instructions:
> ffffffff8ce00080 [unknown] ([unknown])
>             perf  352917 49604.161099:     181013 instructions:
> ffffffff8ce00080 [unknown] ([unknown])
>             perf  352917 49604.161115:       8811 instructions:
> 7f155cad22d0 strcmp+0x8b0
> (/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
>             perf  352917 49604.161115:       8811 instructions:
> 7f155cad22d0 strcmp+0x8b0
> (/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
>             perf  352917 49604.161130:      10483 instructions:
> 7f155caba508 _dl_new_object+0x198
> (/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
>             perf  352917 49604.161130:      10483 instructions:
> 7f155caba508 _dl_new_object+0x198
> (/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
>             perf  352917 49604.165156:     177355 instructions:
> 7f155cab90a4 _dl_lookup_symbol_x+0x44
> (/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
>             perf  352917 49604.165156:   13313598 instructions:
> 7f155cab90a4 _dl_lookup_symbol_x+0x44
> (/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
> ...
> ```
>
> Dapeng/Kan, any thoughts why the counts don't match for instructions
> but did for branches?


That looks strange,  what's your kernel version and perf-tool version? I
just tried the latest perf-tools-next branch, but I don't see this issue.



>
> Thanks,
> Ian