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From:   Ilya Pronin <ipronin@twitter.com>
Date:   Thu, 8 Mar 2018 13:52:15 -0800
Message-ID: <CA+Xn3kzwsHZU7wbgVVVGTtu-En9g8mWPTCe5q-8CPETSgMzatw@mail.gmail.com>
Subject: Re: [PATCH] perf stat: fix cvs output format
To:     Andi Kleen <ak@linux.intel.com>
Cc:     Cong Wang <xiyou.wangcong@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        Jiri Olsa <jolsa@redhat.com>
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The patch merely eliminated those 2 unexpected fields. But from what I
saw they were violating the assumption that all lines have the same
number of fields.

On Wed, Mar 7, 2018 at 9:04 AM, Andi Kleen <ak@linux.intel.com> wrote:
> On Tue, Mar 06, 2018 at 12:31:03PM -0800, Ilya Pronin wrote:
>> Speaking from the user's seat. An optional (not just empty) cgroup
>> field is fine as long it consistently appears when requested with -G
>> option. The problem with print_metric_csv() was that in the case of
>> unsupported counters 2 additional empty fields in the output are
>> completely unexpected and not documented anywhere.
>>
>> Andi, in the output example in your commit
>> 92a61f6412d3a09d6462252a522fa79c9290f405 stalled-cycles-backend event
>> has counter run time field, counter run time percentage field, empty
>> metric value, empty metric unit, and then 2 other empty fields. Are
>> they expected? If yes, what are they and why other events, e.g.
>
> No two extra empty fields are not expected. All lines should
> have the same number of fields so that a tool that looks
> at the first like can keep using the same number.
>
> But I don't think that was it what the patch fixed, or did I
> misread it?
>
> -Andi


-- 
Ilya