From: Ingo Molnar <mingo@elte.hu>
To: Jiri Olsa <jolsa@redhat.com>
Cc: "Christoph Hellwig" <hch@infradead.org>,
rostedt@goodmis.org, andi@firstfloor.org, lwoodman@redhat.com,
linux-kernel@vger.kernel.org,
"Peter Zijlstra" <a.p.zijlstra@chello.nl>,
"Frédéric Weisbecker" <fweisbec@gmail.com>
Subject: Re: [PATCH 1/2] tracing,mm - add kernel pagefault tracepoint for x86 & x86_64
Date: Wed, 10 Nov 2010 14:52:44 +0100 [thread overview]
Message-ID: <20101110135244.GA31638@elte.hu> (raw)
In-Reply-To: <20101110134436.GD1949@jolsa.brq.redhat.com>
* Jiri Olsa <jolsa@redhat.com> wrote:
> On Wed, Nov 10, 2010 at 08:29:54AM -0500, Christoph Hellwig wrote:
> > On Wed, Nov 10, 2010 at 12:56:11PM +0100, Jiri Olsa wrote:
> > > + TP_printk("task=%lx, address=%lx, regs=%lx",
> > > + (unsigned long)__entry->task, (unsigned long)__entry->address,
> > > + __entry->regs)
> >
> > How exactly do you use the information in this trace point? Especially
> > the undecoded pt_regs doesn't seem very useful to me at all.
>
> agreed, the registers pointer are not very useful in the trace file output,
> and could be taken away.. just wanted to be complete I guess
>
> but I believe they are useful when you register the mm_kernel_pagefault
> tracepoint and process the information by yourself
That would be expressed in a better and more generic fashion via adding
PERF_SAMPLE_REGS to perf_event_sample_format, and add a ptregs dump in
kernel/perf_event.c, perf_output_sample(). That way any tracepoint can request a
(user-space)ptregs state snapshot, not just the pagefault ones.
Thanks,
Ingo
next prev parent reply other threads:[~2010-11-10 13:53 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-10 11:56 [PATCH 0/2] tracing,mm - add kernel pagefault tracepoint for x86 & x86_64 Jiri Olsa
2010-11-10 11:56 ` [PATCH 1/2] " Jiri Olsa
2010-11-10 13:29 ` Christoph Hellwig
2010-11-10 13:44 ` Jiri Olsa
2010-11-10 13:52 ` Ingo Molnar [this message]
2010-11-10 15:00 ` Frederic Weisbecker
2010-11-10 15:17 ` Jiri Olsa
2010-11-10 15:20 ` Christoph Hellwig
2010-11-10 16:28 ` Andi Kleen
2010-11-10 16:44 ` Frederic Weisbecker
2010-11-11 9:09 ` [PATCHv2 0/2] " Jiri Olsa
2010-11-11 9:09 ` [PATCHv2 1/2] tracing - fix recursive user stack trace Jiri Olsa
2010-11-11 10:34 ` Andi Kleen
2010-11-11 9:09 ` [PATCHv2 2/2] tracing,mm - add kernel pagefault tracepoint for x86 & x86_64 Jiri Olsa
2010-11-11 12:51 ` Christoph Hellwig
2010-11-11 13:15 ` Jiri Olsa
2010-11-15 13:43 ` Frederic Weisbecker
2010-11-15 14:06 ` Andi Kleen
2010-11-15 14:54 ` Frederic Weisbecker
2010-11-15 15:04 ` Steven Rostedt
2010-11-15 14:19 ` Steven Rostedt
2010-11-16 9:23 ` Jiri Olsa
2010-11-16 13:13 ` Steven Rostedt
2010-11-10 11:56 ` [PATCH 2/2] tracing - fix recursive user stack trace Jiri Olsa
2010-11-11 0:13 ` Li Zefan
2010-11-11 21:57 ` Steven Rostedt
2010-11-18 14:05 ` [tip:perf/core] tracing: Fix " tip-bot for Steven Rostedt
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=20101110135244.GA31638@elte.hu \
--to=mingo@elte.hu \
--cc=a.p.zijlstra@chello.nl \
--cc=andi@firstfloor.org \
--cc=fweisbec@gmail.com \
--cc=hch@infradead.org \
--cc=jolsa@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=lwoodman@redhat.com \
--cc=rostedt@goodmis.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).