From: John Levon <levon@movementarian.org>
To: linux-kernel@vger.kernel.org
Cc: ak@suse.de
Subject: Re: [PATCH][RFC] oprofile for 2.5.39
Date: Sun, 29 Sep 2002 03:52:25 +0100 [thread overview]
Message-ID: <20020929025224.GA68153@compsoc.man.ac.uk> (raw)
In-Reply-To: <p737kh5sf45.fsf@oldwotan.suse.de>
On Sun, Sep 29, 2002 at 04:29:14AM +0200, Andi Kleen wrote:
> Can you explain what you need the context switch hook for ?
Hmm, I tried to explain this in comments in the patch ...
> I don't think it's a good idea to put a hook at such a critical place.
... but I obviously didn't do a very good job.
We need a context to look up the EIP against when we process each sample
in buffer_sync.c. We could just log current at sample time along with
EIP/event, but why would it be preferrable to just logging the same
information once when it's needed ?
Basically it's a matter of :
task_struct *
EIP/Event
EIP/Event
EIP/Event
EIP/Event
....
versus
task_struct */EIP/Event
task_struct */EIP/Event
task_struct */EIP/Event
task_struct */EIP/Event
task_struct */EIP/Event
....
Where task_struct is the same as the previous entry for the vast
majority of entries.
> 2.4 oprofile worked without such a hook, no ?
Sure, but it was ugly as hell (and worked completely differently)
regards
john
--
"When your name is Winner, that's it. You don't need a nickname."
- Loser Lane
next prev parent reply other threads:[~2002-09-29 2:47 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 [this message]
2002-09-29 3:08 ` Andi Kleen
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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