Message-ID: <49E7C74A.8030100@goop.org>
Date: Thu, 16 Apr 2009 17:03:22 -0700
From: Jeremy Fitzhardinge <jeremy@goop.org>
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To: Mathieu Desnoyers <compudj@krystal.dyndns.org>
CC: Steven Rostedt <rostedt@goodmis.org>, linux-kernel@vger.kernel.org,
       Ingo Molnar <mingo@elte.hu>, Andrew Morton <akpm@linux-foundation.org>,
       Thomas Gleixner <tglx@linutronix.de>,
       Peter Zijlstra <peterz@infradead.org>,
       Frederic Weisbecker <fweisbec@gmail.com>, Theodore Tso <tytso@mit.edu>,
       Arjan van de Ven <arjan@infradead.org>, Christoph Hellwig <hch@lst.de>,
       Lai Jiangshan <laijs@cn.fujitsu.com>, Zhaolei <zhaolei@cn.fujitsu.com>,
       Li Zefan <lizf@cn.fujitsu.com>,
       KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
       Masami Hiramatsu <mhiramat@redhat.com>,
       "Frank Ch. Eigler" <fche@elastic.org>, Tom Zanussi <tzanussi@gmail.com>,
       Jiaying Zhang <jiayingz@google.com>, Michael Rubin <mrubin@google.com>,
       Martin Bligh <mbligh@google.com>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>,
       Neil Horman <nhorman@tuxdriver.com>,
       Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>,
       Pekka Enberg <penberg@cs.helsinki.fi>
Subject: Re: [PATCH 2/8] tracing: create automated trace defines
References: <20090414172337.280621613@goodmis.org> <20090414172640.796858018@goodmis.org> <49E51FC1.8090306@goop.org> <20090415014548.GA7984@Krystal> <49E6065B.7080409@goop.org> <20090416023456.GC22378@Krystal> <49E69E76.9030608@goop.org> <20090416234410.GA20513@Krystal>
In-Reply-To: <20090416234410.GA20513@Krystal>
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Mathieu Desnoyers wrote:
> The other point I dislike about the out-of-line approach is that the
> tracer will suffer from a pointless supplementary function call at each
> event. Given how slow function calls are, at least on x86, I'd prefer
> leaving the handler call chain inline, unless there is a very strong
> reason not to do so.
>   

Are they?  They're generally considered to be "free", because the call 
and return are predicted 100% accurately.

> I'll come up with a patch that leaves the tracepoint inline, but fixes
> the header dependency.
>   
OK.

    J
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