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From: ahmadkhorrami <ahmadkhorrami@ut.ac.ir>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Linux-trace Users <linux-trace-users@vger.kernel.org>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	linux-trace-users-owner@vger.kernel.org,
	Jin Yao <yao.jin@linux.intel.com>
Subject: Re: Re: Wrong Perf Backtraces
Date: Mon, 23 Mar 2020 14:33:24 +0430
Message-ID: <ee43289d91fcae1c9ef5cc2429dc916b@ut.ac.ir> (raw)
In-Reply-To: <20200323084942.GA1534489@krava>

Hi,
It seems that my previous e-mail is not sent, properly. So, here is a 
link to the stackoverflow question:
https://stackoverflow.com/questions/60766026/wrong-perf-backtraces

The perf is for Ubuntu 18.04 with the following "uname -a" output:
Linux Ahmad-Laptop 5.0.0-37-generic #40~18.04.1-Ubuntu SMP Thu Nov 14 
12:06:39 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
I also used a compiled Linux-5.4.7 kernel and its corresponding Perf 
tool.

Regards.

On 2020-03-23 13:19, Jiri Olsa wrote:

> On Mon, Mar 23, 2020 at 07:48:26AM +0430, ahmadkhorrami wrote:
> 
>> Here is a link to the detailed question at Stackoverflow:
>> 
>> https://stackoverflow.com/questions/60766026/wrong-perf-backtraces
> 
> hi,
> what perf version are you running?
> 
> jirka
> 
> I can copy it here, if needed.
> 
> Thanks
> 
> On 2020-03-23 05:04, Steven Rostedt wrote:
> 
> On Mon, 23 Mar 2020 00:54:01 +0430
> ahmadkhorrami <ahmadkhorrami@ut.ac.ir> wrote:
> 
> Hi,
> I used "Perf" to extract call graphs in an evince benchmark. The 
> command
> used is as follows:
> sudo perf record -d --call-graph dwarf -c 10000 e
> mem_load_uops_retired.l3_miss:uppp /opt/evince-3.28.4/bin/evince
> 
> I extracted the backtraces using "perf script" and found out that there
> are many corrupted backtrace instances. Some contained repeated 
> function
> calls, for example two consecutive gmallocn()s exactly at the same
> offsets. There are also some backtraces where the callers and callees 
> do
> not match.
> Could you show some examples of the backtraces you mention?
> 
> Note that that mappings are correct. In other words, each single line 
> of
> the reported backtraces is correct (i.e., addresses match with
> functions). But is seems that there are some function calls in the
> middle, which are missed by "Perf". Strangely, in all runs (and also
> with different sampling frequencies) the problem occurs exactly at the
> same place.
> 
> I am really confused and looking forward to any help. I can also send
> backtraces if needed.
> -- Steve

  reply index

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <157597d74ff17f781d9de7e7e3defd13@ut.ac.ir>
2020-03-22 20:24 ` ahmadkhorrami
2020-03-23  0:34   ` Steven Rostedt
     [not found]     ` <21b3df4080709f193d62b159887e2a83@ut.ac.ir>
2020-03-23  8:49       ` Jiri Olsa
2020-03-23 10:03         ` ahmadkhorrami [this message]
2020-03-25 15:18           ` ahmadkhorrami
2020-03-25 15:46             ` Jiri Olsa
2020-03-25 18:54               ` ahmadkhorrami
2020-03-25 18:58               ` Arnaldo Carvalho de Melo
2020-03-25 19:10                 ` ahmadkhorrami
2020-03-25 19:28                   ` Arnaldo Carvalho de Melo
2020-03-25 20:01                     ` ahmadkhorrami
2020-03-25 20:39                       ` Jiri Olsa
2020-03-25 21:02                         ` Jiri Olsa
2020-03-25 21:09                           ` Steven Rostedt
2020-03-25 21:37                             ` ahmadkhorrami
2020-03-25 21:46                               ` Jiri Olsa
2020-03-25 22:21                                 ` ahmadkhorrami
2020-03-25 23:09                                   ` ahmadkhorrami
2020-03-26  9:59                                     ` Jiri Olsa
2020-03-26 13:20                                       ` ahmadkhorrami
2020-03-26 15:39                                         ` Jiri Olsa
2020-03-26 18:19                                           ` ahmadkhorrami
2020-03-26 18:21                                             ` ahmadkhorrami
2020-03-27  9:20                                             ` Jiri Olsa
2020-03-27 10:59                                               ` ahmadkhorrami
2020-03-27 11:04                                                 ` ahmadkhorrami
2020-03-27 12:10                                                   ` Milian Wolff
2020-03-27 12:58                                                     ` ahmadkhorrami
2020-03-27 13:25                                                       ` Milian Wolff
2020-03-27 13:33                                                         ` ahmadkhorrami
2020-03-27 18:43                                                   ` ahmadkhorrami
2020-03-27 22:37                                                     ` Jiri Olsa
2020-03-27 23:12                                                       ` ahmadkhorrami
2020-03-28 23:34                                                         ` Jiri Olsa
2020-03-29  0:43                                                           ` ahmadkhorrami
2020-03-29  1:16                                                             ` ahmadkhorrami
2020-03-29 11:19                                                               ` Jiri Olsa
2020-03-29 11:52                                                                 ` ahmadkhorrami
2020-03-29 12:08                                                                   ` Jiri Olsa
2020-03-29 12:39                                                                     ` ahmadkhorrami
2020-03-29 13:50                                                                       ` Milian Wolff
2020-03-29 14:23                                                                         ` ahmadkhorrami
2020-03-29 19:20                                                                         ` Jiri Olsa
2020-03-30  6:09                                                                           ` Milian Wolff
2020-03-30 13:07                                                                             ` Jiri Olsa
2020-03-30 13:49                                                                               ` ahmadkhorrami
2020-03-30 19:05                                                                                 ` ahmadkhorrami
2020-03-30 21:05                                                                                   ` debuginfod-based dwarf downloading, was " Frank Ch. Eigler
2020-03-31  9:26                                                                                     ` Jiri Olsa
2020-03-31 14:00                                                                                       ` Frank Ch. Eigler
2020-03-31  4:43                                                                                   ` ahmadkhorrami
2020-03-31  9:30                                                                                     ` Jiri Olsa
2020-03-31 11:53                                                                                       ` ahmadkhorrami
2020-03-31 12:43                                                                                   ` ahmadkhorrami
2020-03-31 13:20                                                                                     ` Jiri Olsa
2020-03-31 13:39                                                                                       ` ahmadkhorrami
2020-03-31 14:44                                                                                         ` Milian Wolff
2020-03-31 15:02                                                                                           ` ahmadkhorrami
2020-03-31 15:05                                                                                             ` ahmadkhorrami
2020-03-31 15:29                                                                                             ` Milian Wolff
2020-03-31 16:10                                                                                               ` Arnaldo Carvalho de Melo
2020-03-31 19:20                                                                                                 ` ahmadkhorrami
2020-03-31 19:17                                                                                               ` ahmadkhorrami
2020-03-31 20:57                                                                                               ` ahmadkhorrami
2020-04-04  1:01                                                                                                 ` ahmadkhorrami
2020-04-11 16:42                                                                                                   ` ahmadkhorrami
2020-04-11 21:04                                                                                                     ` ahmadkhorrami

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