Date: Mon, 21 Jul 2014 18:35:37 -0400 (EDT)
From: Nicolas Pitre <nicolas.pitre@linaro.org>
To: Davidlohr Bueso <davidlohr@hp.com>
cc: Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@redhat.com>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Russell King - ARM Linux <linux@arm.linux.org.uk>,
        Catalin Marinas <catalin.marinas@arm.com>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linaro-kernel@lists.linaro.org
Subject: Re: [PATCH 4/4] (RFC) X86: add IPI tracepoints
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On Sun, 20 Jul 2014, Davidlohr Bueso wrote:

> On Fri, 2014-07-18 at 01:18 -0400, Nicolas Pitre wrote:
> > On X86 there are already tracepoints for IRQ vectors through which IPIs
> > are handled.  However this is highly X86 specific, and the IPI signaling
> > is not currently traced.
> > 
> > This is an attempt at adding generic IPI tracepoints to X86.
> 
> I welcome this, and fwiw have been trying out this patch. One thing I
> would like to see, but due to overhead would probably be better suited
> in userspace (trace-cmd, maybe?), is a more packed description of the
> IPI. Ie: unifying ipi_init and ipi_exit and show overall cost of the
> IPI.

That's best suited for the tool consuming the log in user space.  The 
same is done with IRQ events already.


Nicolas
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