From: Jiri Olsa <jolsa@redhat.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>,
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>
Subject: Re: [PATCH 1/2] tracing,mm - add kernel pagefault tracepoint for x86 & x86_64
Date: Wed, 10 Nov 2010 16:17:50 +0100 [thread overview]
Message-ID: <20101110151750.GA11541@jolsa.brq.redhat.com> (raw)
In-Reply-To: <20101110150021.GA5750@nowhere>
On Wed, Nov 10, 2010 at 04:00:25PM +0100, Frederic Weisbecker wrote:
> On Wed, Nov 10, 2010 at 02:52:44PM +0100, Ingo Molnar wrote:
> >
> > * 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
>
>
> We are going to have that with the dwarf based callchain patchset. I'm cooking
> this.
>
> Thanks.
>
I guess I can take the regs out then.. would that patch be acceptable
afterwards..?
thanks,
jirka
next prev parent reply other threads:[~2010-11-10 15:18 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
2010-11-10 15:00 ` Frederic Weisbecker
2010-11-10 15:17 ` Jiri Olsa [this message]
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
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