From: Jiri Olsa <jolsa@redhat.com>
To: Jean Pihet <jean.pihet@linaro.org>
Cc: David Ahern <dsahern@gmail.com>, linux-kernel@vger.kernel.org
Subject: Re: Fwd: perf: callchain feature on ARM - question about libunwind API
Date: Fri, 30 Aug 2013 13:49:03 +0200 [thread overview]
Message-ID: <20130830114903.GC1023@krava.brq.redhat.com> (raw)
In-Reply-To: <CAFrcx1=U8SapYd=Hw8YaAnKNggJMuY4r03zYeevc0Ttq5hFr7Q@mail.gmail.com>
On Thu, Aug 29, 2013 at 07:15:00PM +0200, Jean Pihet wrote:
SNIP
>
> The problem is that it is slow as hell (couple of minutes to report
> the callchain from a simple test app ;-|). I will look at the sampling
> rate and the caching next.
FYI there's elfutils alternative grewing now via libdw providing
API to do the 'remote unwind' as in libunwind. I'm not completely
sure, but I think it should support both .eh_frames and .debug_frames.
check:
git://git.fedorahosted.org/git/elfutils.git branch jankratochvil/unwindx86
the 'tests/backtrace-data.c' should be an example of what we want in perf
somewhere I should have perf changes to support this in
early version which no longer relevant.. but I recall it
was substantially faster due to some libdw inner caching
it's on my long term TODO list, so any help is welcome! ;-)
jirka
next prev parent reply other threads:[~2013-08-30 11:49 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAFrcx1n5eA4zz+nUhraE_fi_Usc=PCZTC=RCT=S285K4=jqHSg@mail.gmail.com>
2013-08-27 11:58 ` Jean Pihet
2013-08-27 16:12 ` David Ahern
2013-08-29 13:52 ` Jiri Olsa
2013-08-29 17:15 ` Jean Pihet
2013-08-30 11:49 ` Jiri Olsa [this message]
2013-08-30 11:56 ` Jiri Olsa
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