From: Andi Kleen <ak@suse.de>
To: John Levon <levon@movementarian.org>
Cc: linux-kernel@vger.kernel.org, ak@suse.de
Subject: Re: [PATCH][RFC] oprofile for 2.5.39
Date: Sun, 29 Sep 2002 05:08:07 +0200 [thread overview]
Message-ID: <20020929050807.A17869@wotan.suse.de> (raw)
In-Reply-To: <20020929025224.GA68153@compsoc.man.ac.uk>
>
> Basically it's a matter of :
>
> task_struct *
> EIP/Event
> EIP/Event
> EIP/Event
> EIP/Event
> ....
I think you can easily do that by keeping state per cpu in the
NMI handler.
if (current == __get_cpu_var(oprofile_cpustate)) {
/* log current */
__get_cpu_var(oprofile_cpustate) = current;
} else {
/* do nothing */
}
/* log EIP */
[or when you are an module use an cache line padded array indexed with
smp_processor_id - per cpu data doesn't work from modules]
This is even more efficient because when the NMI rate is lower than
the task switch frequency (which is not unlikely) then you'll avoid
many useless task_struct loggings.
-Andi
next prev parent reply other threads:[~2002-09-29 3:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20020929014440.GA66796@compsoc.man.ac.uk.suse.lists.linux.kernel>
2002-09-29 2:29 ` [PATCH][RFC] oprofile for 2.5.39 Andi Kleen
2002-09-29 2:52 ` John Levon
2002-09-29 3:08 ` Andi Kleen [this message]
2002-09-29 3:14 ` Andi Kleen
2002-09-29 3:27 ` John Levon
2002-09-29 4:11 ` Anton Blanchard
2002-09-29 3:47 ` Andrew Morton
2002-09-29 3:53 ` John Levon
2002-09-29 1:44 John Levon
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