Re: [PATCH v2] arm: add cpu_idle tracepoints to arch_cpu_idle

From: Jisheng Zhang
Date: Thu Sep 17 2015 - 04:48:42 EST


Dear Steven,

On Thu, 17 Sep 2015 16:07:44 +0800
Jisheng Zhang <jszhang@xxxxxxxxxxx> wrote:

> Dear all,
>
> On Thu, 17 Sep 2015 01:32:40 +0800
> Jisheng Zhang <jszhang@xxxxxxxxxxx> wrote:
>
> > Currently, if cpuidle is disabled or not supported, powertop reports
> > zero wakeups and zero events. This is due to the cpu_idle tracepoints
> > are missing.
> >
> > This patch is to make cpu_idle tracepoints always available even if
> > cpuidle is disabled or not supported.
> >
> > Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxxx>
> > ---
> > Since v1:
> > - ignore arm_pm_idle.
>
> Something related: let's have a look at arch/arm/mach-omap2/pm34xx.c
> the omap3_pm_idle(void) function, it uses trace_cpu_idle(), should we
> use the _rcuidle version as below:

484546509ce5 ("x86/tracing: Denote the power and cpuidle tracepoints as
_rcuidle()") make me think we need to fix omap3_pm_idle, right?

Thanks,
Jisheng

>
> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
> index 87b98bf9..b3bc972 100644
> --- a/arch/arm/mach-omap2/pm34xx.c
> +++ b/arch/arm/mach-omap2/pm34xx.c
> @@ -301,11 +301,11 @@ static void omap3_pm_idle(void)
> if (omap_irq_pending())
> return;
>
> - trace_cpu_idle(1, smp_processor_id());
> + trace_cpu_rcuidle(1, smp_processor_id());
>
> omap_sram_idle();
>
> - trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id());
> + trace_cpu_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
> }
>
> #ifdef CONFIG_SUSPEND
>
>
>
> > arch/arm/kernel/process.c | 11 ++++++++---
> > 1 file changed, 8 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
> > index 7a7c4ce..83d2dc5 100644
> > --- a/arch/arm/kernel/process.c
> > +++ b/arch/arm/kernel/process.c
> > @@ -28,6 +28,7 @@
> > #include <linux/random.h>
> > #include <linux/hw_breakpoint.h>
> > #include <linux/leds.h>
> > +#include <trace/events/power.h>
> >
> > #include <asm/processor.h>
> > #include <asm/thread_notify.h>
> > @@ -66,11 +67,15 @@ void (*arm_pm_idle)(void);
> >
> > void arch_cpu_idle(void)
> > {
> > - if (arm_pm_idle)
> > + if (arm_pm_idle) {
> > arm_pm_idle();
> > - else
> > + local_irq_enable();
> > + } else {
> > + trace_cpu_idle_rcuidle(1, smp_processor_id());
> > cpu_do_idle();
> > - local_irq_enable();
> > + local_irq_enable();
> > + trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
> > + }
> > }
> >
> > void arch_cpu_idle_prepare(void)
>
>
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