linux-kernel - Re: [PATCH] perf report: Fix wrong jump arrow

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Date:   Mon, 12 Feb 2018 20:24:07 +0800
From:   "Jin, Yao" <yao.jin@...ux.intel.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     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] perf report: Fix wrong jump arrow

Hi Arnaldo,

Thanks for applying the patch. Yes the issue only happens on skl+.

The committer notes are very good and clear.

Thanks
Jin Yao

On 2/9/2018 11:15 PM, Arnaldo Carvalho de Melo wrote:
> Em Mon, Jan 29, 2018 at 06:57:53PM +0800, Jin Yao escreveu:
>> When we use perf report interactive annotate view, we can see
>> the position of jump arrow is not correct. For example,
>>
>> 1. perf record -b ...
>> 2. perf report
>> 3. In interactive mode, select Annotate 'function'
>>
>> Percent│ IPC Cycle
>>         │                                if (flag)
>>    1.37 │0.4┌──   1      ↓ je     82
>>         │   │                                    x += x / y + y / x;
> 
> Applied and added this to the cset log, please check:
> 
> Committer notes:
> 
> Please note that only from LBRv5 (according to Jiri) onwards, i.e. >=
> Skylake is that we'll have the cycles counts in each branch record
> entry, so to see the Cycles and IPC columns, and be able to test this
> patch, one need a capable hardware.
> 
> While applying this I first tested it on a Broadwell class machine and
> couldn't get those columns, will add code to the annotate browser to
> warn the user about that, i.e. you have branch records, but no cycles,
> use a more recent hardware to get the cycles and IPC columns.
> 
> - Arnaldo
>