linux-kernel - Re: Getting interrupt every million cache misses

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Message-ID: <20161027082801.GE3568@worktop.programming.kicks-ass.net>
Date:   Thu, 27 Oct 2016 10:28:01 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Pavel Machek <pavel@....cz>
Cc:     acme@...hat.com, kernel list <linux-kernel@...r.kernel.org>,
        mingo@...hat.com, alexander.shishkin@...ux.intel.com
Subject: Re: Getting interrupt every million cache misses

On Wed, Oct 26, 2016 at 10:54:16PM +0200, Pavel Machek wrote:
> Hi!
> 
> I'd like to get an interrupt every million cache misses... to do a
> printk() or something like that. As far as I can tell, modern hardware
> should allow me to do that. AFAICT performance events subsystem can do
> something like that, but I can't figure out where the code is / what I
> should call.
> 
> Can someone help?

Can you go back one step and explain why you would want this? What use
is a printk() on every 1e6-th cache miss.

That is, why doesn't:

 $ perf record -e cache-misses -c 1000000 -a -- sleep 5

suffice?