Get local CPU id

Maxime Ripard maxime.ripard at free-electrons.com
Mon Mar 9 08:59:47 EDT 2015


On Sun, Mar 08, 2015 at 06:30:47PM -0400, Valdis.Kletnieks at vt.edu wrote:
> On Sun, 08 Mar 2015 22:49:00 +0100, Maxime Ripard said:
> 
> > On Sun, Mar 08, 2015 at 10:06:23PM +0300, Matwey V. Kornilov wrote:
> 
> > > I would like to somehow obtain local CPU core ID in the interrupt
> > > handler function. I want to see how my interruptions are distributed
> > > among different CPU cores under different conditions.
> 
> > > How should I do that?
> >
> > To answer strictly your question, like Nick said, smp_processor_id()
> > will work fine.
> >
> > However, you can do exactly what you want be reading /proc/interrupts,
> > that already provide the informations you are looking for.
> 
> Clarification:  /proc/interrupts will give userspace that information.
> It is *not* recommended you try to read it from kernel space, much less
> from an interrupt context... :)

Hmmm, yes, it was a little too obvious in my mind :)

Thanks for the clarification!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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