From: Milian Wolff <milian.wolff@kdab.com>
To: David Hinkle <david.hinkle@securly.com>
Cc: Hadrien Grasland <grasland@lal.in2p3.fr>,
linux-perf-users@vger.kernel.org
Subject: Re: Trying to understand some strange samples in a perf profile
Date: Thu, 04 Jan 2018 23:08:17 +0100 [thread overview]
Message-ID: <10526114.Hqjjc3tiqt@agathebauer> (raw)
In-Reply-To: <CAOrDofTn68XiBjEvF=boM94LwfXUt_W-AhCoOsK7aijiOknyfQ@mail.gmail.com>
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On Friday, December 29, 2017 12:31:41 AM CET David Hinkle wrote:
> > - build a minimal "unwinder" application for libunwind e.g.
> > - notify libunwind about all mmap events
> > - install the register and stack state from the per.data file
> > - try to unwind, see what happens
>
> I'm having some problems with perf dwarf stack unwindings that stop at
> the kernel/userspace boundary and some userspace stacks that aren't
> unwinding at all on 4.9.70 I'd really love to shed some light on.
> Similar situation, in my case the stacks are in libc-2.17.so, which I
> think is symbolized properly (Other traces are unwinding through this
> library fine). I'm also using libdw for unwinding and not libunwind.
>
> I'd love to be able to do the above 4 things in an app and see if I
> can figure out why it's not unwinding properly. Do you have some
> example code that can do that? If you do now or you write it please
> share.
I don't have anything ready-made, otherwise I'd have shared it already. The
example code for what needs to be done would be the perf code base. I.e. have
a look at tools/perf/util/unwind-{libunwind-local,libdw}.c
Cheers
--
Milian Wolff | milian.wolff@kdab.com | Senior Software Engineer
KDAB (Deutschland) GmbH, a KDAB Group company
Tel: +49-30-521325470
KDAB - The Qt, C++ and OpenGL Experts
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prev parent reply other threads:[~2018-01-04 22:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-20 9:39 Trying to understand some strange samples in a perf profile Hadrien Grasland
2017-12-21 9:54 ` Milian Wolff
2017-12-21 10:46 ` Hadrien Grasland
2017-12-21 12:47 ` Milian Wolff
2017-12-21 16:02 ` Hadrien Grasland
2017-12-27 22:21 ` Milian Wolff
2017-12-28 23:31 ` David Hinkle
2018-01-04 22:08 ` Milian Wolff [this message]
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