On Tue, 2017-01-24 at 13:49 +0000, Julien Grall wrote:
> On 24/01/17 13:40, Dario Faggioli wrote:
> > Ah, wow... And how --forgive my naiveness-- do you measure / check
> > that?
>
> I added a print in the interrupt path (gic_interrupt for ARM) to
> dump
> the interrupt number. This needs to be restrict to CPU2 and above to
> avoid been flooded:
>
> if ( smp_processor_id() > 1 )
> printk("%s: CPU%u IRQ%u\n", __FUNCTION__, smp_processor_id(),
> irq);
>
Ok.> I also added a print in the idle loop before and after the idling > instruction (wfi for ARM, pm_idle for x86 I think). You can see the > CPU > to go in idle mode but never coming back. > I see. Yes, this is very different on x86. There, we have tracing (BTW, did that made it to ARM eventually?) and there's TRC_PM_IDLE_ENTRY/EXIT which do pretty much the same of your printk-s. And if I look at it, I do see even totally idle (from the scheduler point of view) pCPUs, I indeed see them going back and forth from and to C3. Dario -- <<This happens because I choose it to happen!>> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)
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