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Subject: Re: [PATCH] tracing: Cleanup the convoluted softirq tracepoints
From: Steven Rostedt <rostedt@goodmis.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Koki Sanagi <sanagi.koki@jp.fujitsu.com>,
        Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@elte.hu>,
        Frederic Weisbecker <fweisbec@gmail.com>, nhorman@tuxdriver.com,
        scott.a.mcmillan@intel.com, laijs@cn.fujitsu.com,
        "H. Peter Anvin" <hpa@zytor.com>, LKML <linux-kernel@vger.kernel.org>,
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        David Miller <davem@davemloft.net>, izumi.taku@jp.fujitsu.com,
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        Heiko Carstens <heiko.carstens@de.ibm.com>,
        "Luck, Tony" <tony.luck@intel.com>
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Date: Tue, 19 Oct 2010 10:46:39 -0400
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On Tue, 2010-10-19 at 16:07 +0200, Thomas Gleixner wrote:

> The vector computation is compared to the extra tracing induced jumps
> probably not even measurable. Stop defending horrible coding with
> handwavy performance and impact arguments.

Yes this was crappy code, I'm not defending it. But this code was from
the original tracepoints. I just looked at when this code was added, and
it was still in the time TRACE_EVENT() was in a major flux. Heck, the
code resided in include/trace/irq.h and not include/trace/events/irq.h.
And yes, a lot of decisions back then were put on handwaving performance
and impact, and it was not just coming from us.

I admit I should have cleaned it up, but I did not want to touch it
until it actually broke ;-)

-- Steve