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Date: Mon, 12 Mar 2012 11:21:00 -0700
From: Arun Sharma <asharma@fb.com>
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To: Namhyung Kim <namhyung.kim@lge.com>
CC: <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Mike Galbraith <efault@gmx.de>, Paul Mackerras <paulus@samba.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Stephane Eranian <eranian@google.com>,
        Tom Zanussi <tzanussi@gmail.com>, <linux-perf-users@vger.kernel.org>
Subject: Re: [PATCH 0/2] perf: add sort by inclusive time functionality (v2)
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On 3/12/12 12:43 AM, Namhyung Kim wrote:

>> Known bugs:
>>
>> total_period computation is broken for order=callee
>>
>
> I'd like to add two more :).
>
> * If perf record misses callchain info, perf report will get stuck.
> * If it's used with "symbol" sort order, it'll get stuck too.
>

Can you post the command lines you used to reproduce this? A backtrace 
on where perf report is getting stuck would be useful as well.

Since I didn't make any changes to the perf record or perf report code 
paths that don't involve "-s inclusive", I wonder if you see the same 
issues without my patch.

For missing callchain info cases, I'd expect cursor->nr to be zero. So 
loops such as:

+       for (i = 0; i < cursor->nr; i++) {

should terminate immediately.

>
> BTW, I don't like the name 'inclusive' as a sort key. If it cares about
> time, IMHO, the name should contain 'time' - something like 'itime' or
> 'inctime'?

The existing sort orders: pid, comm, dso, symbol, parent -- all care 
about time, but none of them have time in their name?

>
> Furthermore, I don't think it is a sort key. As it doesn't sort
> anything, and only affects the way calculating symbol's period value,
> wouldn't it be better making it a separate switch rather than a sort
> key? Plus, checking whether it has callchain data and symbol sort key
> might be added also.

Yes, we're still sorting by period, but a redefined meaning of period 
(please see my other mail about period vs period_self). Previous 
iterations of this code did use a top level flag, but that namespace is 
getting a bit crowded.

  -Arun