From: Arun Sharma <asharma@fb.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: 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-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org
Subject: Re: [RFC] Sort inclusive
Date: Tue, 6 Mar 2012 11:41:38 -0800 [thread overview]
Message-ID: <4F566872.9010408@fb.com> (raw)
In-Reply-To: <20120306065753.GB5100@elte.hu>
On 3/5/12 10:57 PM, Ingo Molnar wrote:
> Btw., assuming that you are profiling user-space applications
> via call-chains, how do you deal with the lack of dwarf decoding
> done by perf, in particular on 64-bit x86 systems where most
> distros don't compile call-chains into libraries and
> application? In what practical situations does that limitation
> hinder you and what do you do about it - rebuild your apps with
> frame pointers included?
Yes - we're rebuilding everything with frame pointers so we could get
callchains. While this works for C/C++, I'm not convinced that we have a
good solution for JITs where there may be multiple stacks (eg: one each
for interpreted and JIT code), and the kernel may not be able to unwind
without dwarf decoding. For now, we're going with the /tmp/perf-$pid.txt
based solution for JITs.
I'll post a new patch with the code refactored into smaller functions.
-Arun
WARNING: multiple messages have this Message-ID (diff)
From: Arun Sharma <asharma@fb.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Mike Galbraith <efault@gmx.de>, Paul Mackerras <paulus@samba.org>,
Peter Zijlstra <peterz@infradead.org>,
Stephane Eranian <eranian@google.com>,
Tom Zanussi <tzanussi@gmail.com>, <linux-kernel@vger.kernel.org>,
<linux-perf-users@vger.kernel.org>
Subject: Re: [RFC] Sort inclusive
Date: Tue, 6 Mar 2012 11:41:38 -0800 [thread overview]
Message-ID: <4F566872.9010408@fb.com> (raw)
In-Reply-To: <20120306065753.GB5100@elte.hu>
On 3/5/12 10:57 PM, Ingo Molnar wrote:
> Btw., assuming that you are profiling user-space applications
> via call-chains, how do you deal with the lack of dwarf decoding
> done by perf, in particular on 64-bit x86 systems where most
> distros don't compile call-chains into libraries and
> application? In what practical situations does that limitation
> hinder you and what do you do about it - rebuild your apps with
> frame pointers included?
Yes - we're rebuilding everything with frame pointers so we could get
callchains. While this works for C/C++, I'm not convinced that we have a
good solution for JITs where there may be multiple stacks (eg: one each
for interpreted and JIT code), and the kernel may not be able to unwind
without dwarf decoding. For now, we're going with the /tmp/perf-$pid.txt
based solution for JITs.
I'll post a new patch with the code refactored into smaller functions.
-Arun
next prev parent reply other threads:[~2012-03-06 19:42 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-05 22:12 [RFC] Sort inclusive Arun Sharma
2012-03-05 23:41 ` Arun Sharma
2012-03-06 6:57 ` Ingo Molnar
2012-03-06 19:41 ` Arun Sharma [this message]
2012-03-06 19:41 ` Arun Sharma
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4F566872.9010408@fb.com \
--to=asharma@fb.com \
--cc=acme@redhat.com \
--cc=efault@gmx.de \
--cc=eranian@google.com \
--cc=fweisbec@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-perf-users@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=paulus@samba.org \
--cc=peterz@infradead.org \
--cc=tzanussi@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.