Date: Fri, 25 Aug 2006 16:16:31 -0400
From: Chuck Ebbert <76306.1226@compuserve.com>
Subject: Re: [PATCH 9/18] 2.6.17.9 perfmon2 patch for review:
  kernel-level interface
To: Christoph Hellwig <hch@infradead.org>
Cc: Stephane Eranian <eranian@hpl.hp.com>,
       linux-kernel <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@osdl.org>
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In-Reply-To: <20060825134704.GA21398@infradead.org>

On Fri, 25 Aug 2006 14:47:04 +0100, Christoph Hellwig wrote:

> > This interface is for people writing kprobes who want to do performance
> > monitoring within their probe code.  There will probably never be any
> > in-kernel users, just like there are no in-kernel users of kprobes.
>
> Wrong argument.  There is a in-tree user of kprobes and I plan to submit
> a lot more.

OK.  More than two years after kprobes went into the kernel, a single
in-kernel user has now appeared in 2.6.18-rc: /net/ipv4/tcp_probe.c

So by your argument kprobes should not have been merged until now.

> If people want to write kprobes for performance mintoring
> they should submit them for inclusion and we can then find a proper
> API for it - the current one is rather horrible anyway.

How so?  Last time I tried it I had to manually copy parts of headers 
from libpfm to get the fields but that should be easy to fix.  And
some wrappers around the low-level functions might be nice but again
that's easy to add.

-- 
Chuck

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