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Date: Tue, 1 Apr 2014 13:05:07 +0530
From: Arun Sharma <asharma@fb.com>
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To: Namhyung Kim <namhyung@kernel.org>
CC: Arnaldo Carvalho de Melo <acme@kernel.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Ingo Molnar <mingo@kernel.org>, Paul Mackerras <paulus@samba.org>,
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        Frederic Weisbecker <fweisbec@gmail.com>,
        Andi Kleen <andi@firstfloor.org>, Rodrigo Campos <rodrigo@sdfg.com.ar>
Subject: Re: [PATCHSET 00/21] perf tools: Add support to accumulate hist periods
 (v9)
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On 4/1/14, 12:58 PM, Namhyung Kim wrote:

>>
>> gdb attributes 0x10370 to a different/known symbol.
>>
>> (gdb) x /i 0x10370
>>     0x10370 <get_cie_encoding+160>:      cmp    $0x4c,%dl
>>
>> Is this known? Could this possibly be caused by stale histogram entries from
>> unmapped/remapped shared libs?
>
> Possibly.
>
> Anyway the addr which perf reported is a mapped address so that it's
> pointless to use the addr directly - it's 7f1b0c963370 in fact.
>

Right - that's the address I'd use if the process in question is still 
running. But gdb <dso name> followed by relative addresses could still 
tell us what the right symbol was?

> What was the exact command line though - did you use any filter
> (--comms, --dsos, --symbols) or event modifiers?  Those are another
> possible culprits since map searching code touched by recent changes.

There were no other filters. The command used was just "perf top".

>
> I'm not able to reproduce the problem on my machine.  It'd be great if
> you could bisect or let me know how to reproduce it easily.
>

I don't have a solid repro either. Involves building a binary, running 
"perf top" and waiting for a few mins until that warning popup appears.

Will try to git bisect and figure out potential culprits.

  -Arun
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