From: Frederic Weisbecker <fweisbec@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Paul Mackerras <paulus@samba.org>,
David Miller <davem@davemloft.net>
Subject: Re: [PATCH 2/2] perf: Use hot regs with software sched switch/migrate events
Date: Tue, 30 Mar 2010 00:53:56 +0200 [thread overview]
Message-ID: <20100329225354.GD12254@nowhere> (raw)
In-Reply-To: <20100329224352.GC12254@nowhere>
On Tue, Mar 30, 2010 at 12:43:54AM +0200, Frederic Weisbecker wrote:
> On Mon, Mar 29, 2010 at 08:05:38PM +0200, Peter Zijlstra wrote:
> > On Mon, 2010-03-29 at 19:47 +0200, Frederic Weisbecker wrote:
> > >
> > >
> > > I'm going to make a quick fix for perf_fetch_caller_regs() that
> > > passes task_pt_regs if exclude_kernel for perf/urgent,
> > > and I'll do the above cleanups/invasive fixes on perf/core.
> > >
> > >
> > ok, sounds sensible, thanks!
>
>
> Actually I have doubts about what should be the strict sense
> of exclude_kernel.
>
> Does that mean we exclude any event that happened in the kernel?
> Or does that mean we exclude the part that happened in the kernel?
>
> Depending on the case, we do either.
>
> In perf_swevent_hrtimer(), we simply go back to task_pt_regs()
> if exclude_kernel.
>
> But in other software events, we don't such fix, we actually
> filter out the event if it is not user_mode().
>
> So, I'm a bit confused on what to do.
> I'm tempted to adopt the meaning from perf_swevent_hrtimer()
> for software events too, I'm not sure...
I think this is the right thing to do: jump back to user context
instead of filtering out (unless kernel thread).
Otherwise every software events, trace events included, are totally
pointless with exclude_kernel.
next prev parent reply other threads:[~2010-03-29 22:53 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-28 5:11 [GIT PULL] perf fixes Frederic Weisbecker
2010-03-28 5:11 ` [PATCH 1/2] perf: Correctly align perf event tracing buffer Frederic Weisbecker
2010-03-29 8:51 ` Peter Zijlstra
2010-03-29 17:16 ` Frederic Weisbecker
2010-03-29 17:20 ` Peter Zijlstra
2010-03-29 17:51 ` Frederic Weisbecker
2010-03-28 5:11 ` [PATCH 2/2] perf: Use hot regs with software sched switch/migrate events Frederic Weisbecker
2010-03-29 8:49 ` Peter Zijlstra
2010-03-29 17:47 ` Frederic Weisbecker
2010-03-29 18:05 ` Peter Zijlstra
2010-03-29 22:43 ` Frederic Weisbecker
2010-03-29 22:53 ` Frederic Weisbecker [this message]
2010-03-30 18:54 ` Peter Zijlstra
2010-03-30 19:14 ` Frederic Weisbecker
2010-03-29 3:33 ` [GIT PULL] perf fixes Ingo Molnar
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