Re: [PATCH] perf: fix interrupt handler timing harness

From: Stephane Eranian
Date: Mon Jul 08 2013 - 16:56:43 EST


On Mon, Jul 8, 2013 at 10:54 PM, Andi Kleen <ak@xxxxxxxxxxxxxxxxxx> wrote:
>> I did a quite a bit of ftracing to look for spots inside the handler
>> which were taking large amounts of time. There were none. The
>> execution time was spread very evenly over the entire nmi handler. It
>> didn't appear to be any individual hot cachelines or doing something
>> silly like sitting in a loop handling lots of PMU events.
>
> In some cases callgraphs seemed to be quite expensive (large fraction
> of the handler time)
>
In my case, I am not doing callgraphs, just regular cycles.
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