From: Andi Kleen <andi@firstfloor.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>,
Robert Richter <robert.richter@amd.com>,
Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [2.6.28-rc6] oprofile: "opcontrol --start" output two warnings
Date: Tue, 25 Nov 2008 12:09:35 +0100 [thread overview]
Message-ID: <20081125110935.GF6703@one.firstfloor.org> (raw)
In-Reply-To: <20081125192316.26E5.KOSAKI.MOTOHIRO@jp.fujitsu.com>
> if so, I think get_stagger() is a bit strange.
> it depend on caller cpu. then if PREEMPT=Y, it return radom result.
Even without PREEMPT it is random because there is no guarantee the
init code is executing on CPU 0
>
> I'm not sure about oprofile design.
> but if you are right, I think p4_fill_in_addresses shoudn't use smp_processor_id().
Correct.
>
> Am I missing any point?
No you're right. Always returning 0 in get_stagger() should be ok
I think, at least it wouldn't make anything worse.
Or perhaps figure out if the per cpu addresses are really needed,
if yes then this would need much more changes. But I hope
that would not be needed.
But someone should better test it, the P4 perfmon handling is certainly
hairy and I don't claim to understand all its intricate details.
-Andi
--
ak@linux.intel.com
prev parent reply other threads:[~2008-11-25 10:59 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-25 3:18 KOSAKI Motohiro
2008-11-25 10:09 ` Andi Kleen
2008-11-25 10:29 ` KOSAKI Motohiro
2008-11-25 11:09 ` Andi Kleen [this message]
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