linux-kernel - Re: [PATCH v7] perf annotate: Fix sample events lost in stdio mode

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Date:   Wed, 31 Mar 2021 10:18:34 +0800
From:   Yang Jihong <yangjihong1@...wei.com>
To:     Namhyung Kim <namhyung@...nel.org>
CC:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Yao Jin <yao.jin@...ux.intel.com>, <gustavoars@...nel.org>,
        <mliska@...e.cz>, linux-kernel <linux-kernel@...r.kernel.org>,
        <zhangjinhao2@...wei.com>
Subject: Re: [PATCH v7] perf annotate: Fix sample events lost in stdio mode

Hello, Namhyung  and Arnaldo,

On 2021/3/30 15:26, Namhyung Kim wrote:
> Hi Yang and Arnaldo,
> 
> On Sat, Mar 27, 2021 at 11:16 AM Yang Jihong <yangjihong1@...wei.com> wrote:
>> On 2021/3/26 20:06, Arnaldo Carvalho de Melo wrote:
>>> So it seems to be working, what am I missing? Is this strictly non
>>> group related?
>>>
>> Yes, it is non group related.
>> This problem occurs only when different events need to be recorded at
>> the same time, i.e.:
>> perf record -e branch-misses -e branch-instructions -a sleep 1
>>
>> The output results of perf script and perf annotate do not match.
>> Some events are not output in perf annotate.
> 
> Yeah I think it's related to sort keys.  The code works with a single
> hist_entry for each event and symbol.  But the default sort key
> creates multiple entries for different threads and it causes the
> confusion.
> 
Yes, After revome zfree from hists__find_annotations, the output of perf 
annotate is repeated, which is related to sort keys.

The original problem is that notes->src may correspond to multiple 
sample events. Therefore, we cannot simply zfree notes->src to avoid 
repeated output.

Arnaldo, is there any problem with this patch? :)

Thanks,
Yang
> Thanks,
> Namhyung
> .
>