linux-kernel - Re: [PATCH 0/2] perf: add sort by inclusive time functionality (v2)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4F5E3E8C.1020005@fb.com>
Date:	Mon, 12 Mar 2012 11:21:00 -0700
From:	Arun Sharma <asharma@...com>
To:	Namhyung Kim <namhyung.kim@....com>
CC:	<linux-kernel@...r.kernel.org>, Ingo Molnar <mingo@...e.hu>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Mike Galbraith <efault@....de>,
	Paul Mackerras <paulus@...ba.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Stephane Eranian <eranian@...gle.com>,
	Tom Zanussi <tzanussi@...il.com>,
	<linux-perf-users@...r.kernel.org>
Subject: Re: [PATCH 0/2] perf: add sort by inclusive time functionality (v2)

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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/