[PATCH] clocksource: arch_timer: Set dynamic irq affinity on mmio clockevent

[PATCH] clocksource: arch_timer: Set dynamic irq affinity on mmio clockevent

[Stephen Boyd]

Set the CLOCK_EVT_FEAT_DYNIRQ flag on the memory mapped
clockevent so that we save power by waking up the CPU with the
next event when this timer is used in broadcast mode.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
 drivers/clocksource/arm_arch_timer.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 95fb944e15ee..57e823c44d2a 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -277,6 +277,7 @@ static void __arch_timer_setup(unsigned type,
 			clk->set_next_event = arch_timer_set_next_event_phys;
 		}
 	} else {
+		clk->features |= CLOCK_EVT_FEAT_DYNIRQ;
 		clk->name = "arch_mem_timer";
 		clk->rating = 400;
 		clk->cpumask = cpu_all_mask;
-- 
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[PATCH] clocksource: arch_timer: Set dynamic irq affinity on mmio clockevent

[Daniel Lezcano]

On 01/06/2014 11:56 PM, Stephen Boyd wrote:
> Set the CLOCK_EVT_FEAT_DYNIRQ flag on the memory mapped
> clockevent so that we save power by waking up the CPU with the
> next event when this timer is used in broadcast mode.
>
> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
> ---
>   drivers/clocksource/arm_arch_timer.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> index 95fb944e15ee..57e823c44d2a 100644
> --- a/drivers/clocksource/arm_arch_timer.c
> +++ b/drivers/clocksource/arm_arch_timer.c
> @@ -277,6 +277,7 @@ static void __arch_timer_setup(unsigned type,
>   			clk->set_next_event = arch_timer_set_next_event_phys;
>   		}
>   	} else {
> +		clk->features |= CLOCK_EVT_FEAT_DYNIRQ;
>   		clk->name = "arch_mem_timer";
>   		clk->rating = 400;
>   		clk->cpumask = cpu_all_mask;
>

Applied in my tree for 3.15.

I am curious how much you saved in your current scenario. Did you had 
time to do some rough measurements ?

Thanks
   -- Daniel



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