linux-kernel - Re: [PATCH] perf dso: Fix dso comparison

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Message-Id: <04413346-1dc6-3f24-7f3d-3783b800780c@linux.ibm.com>
Date:   Tue, 24 Mar 2020 19:12:34 +0530
From:   Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     acme@...nel.org, linux-kernel@...r.kernel.org, namhyung@...nel.org,
        mark.rutland@....com, naveen.n.rao@...ux.vnet.ibm.com,
        Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
Subject: Re: [PATCH] perf dso: Fix dso comparison



On 3/24/20 6:52 PM, Jiri Olsa wrote:
> On Tue, Mar 24, 2020 at 06:07:23PM +0530, Ravi Bangoria wrote:
> 
> SNIP
> 
>>> looks good, do we need to add the dso_id check to sort__dso_cmp?
>>
>> I guess with different filename there is no need to compare dso_id.
>> But for same filename, adding dso_id cmp will separate out the
>> samples:
>>
>> Ex, Without dso_id compare:
>>
>>    $ ./perf report -s dso,dso_size -v
>>      66.63%  /home/ravi/a.out                                  4096
>>      33.36%  /home/ravi/Workspace/linux/tools/perf/a.out       4096
>>
>>    $ ./perf report -s dso,dso_size
>>      99.99%  a.out                 4096
>>
>>
>> With below diff:
>>
>>    -       return strcmp(dso_name_l, dso_name_r);
>>    +       ret = strcmp(dso_name_l, dso_name_r);
>>    +       if (ret)
>>    +               return ret;
>>    +       else
>>    +               return dso__cmp_id(dso_l, dso_r);
>>
>>
>>    $ ./perf report -s dso,dso_size
>>      99.99%  a.out                 4096
>>      33.36%  a.out                 4096
>>
>> though, the o/p also depends which other sort keys are used along
>> with dso key. Do you think this change makes sense?
> 
> the above behaviour is something I'd expect from 'dso'
> sort key to do - separate out different dsos, even with
> the same name

Yes it does that as well...

   $ ./perf report -s dso
     66.63%  a.out
     33.36%  a.out

Ravi