linux-kernel - Re: [PATCH 1/2] perf script: Show virtual addresses instead of offsets

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Date:   Fri, 18 May 2018 10:03:44 +0530
From:   Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>, jolsa@...hat.com
Cc:     Sandipan Das <sandipan@...ux.vnet.ibm.com>,
        linux-kernel@...r.kernel.org, naveen.n.rao@...ux.vnet.ibm.com
Subject: Re: [PATCH 1/2] perf script: Show virtual addresses instead of
 offsets

Arnaldo,

We already have a binary offset handy in perf code but there is no way to
dump it with perf script. We can derive it from symname+symoff but that's
a manual work.

Will it be good to have a '-F binoff' option?

Ravi


On 05/18/2018 01:29 AM, Arnaldo Carvalho de Melo wrote:
> Em Thu, May 17, 2018 at 12:03:25PM +0530, Sandipan Das escreveu:
>> When perf data is recorded with the call-graph option enabled,
>> the callchain shown by perf script shows the binary offsets of
>> the symbols as the ip. This is incorrect for kernel symbols as
>> the ip values are always off by a fixed offset depending on the
>> architecture. If the offsets from the start of the symbols are
>> printed, they are also incorrect for both kernel and userspace
>> symbols.
>>
>> Without the call-graph option, the callchain shows the virtual
>> addresses of the symbols rather than their binary offsets. The
>> offsets printed in this case are also correct.
>>
>> This fixes the inconsistency in perf script's output.
> 
> Thanks, tested and applied,
> 
> - Arnaldo
>