Re: [PATCH] clocksource: arch_timer: Set dynamic irq affinity onmmio clockevent

From: Daniel Lezcano
Date: Tue Jan 14 2014 - 03:40:22 EST


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@xxxxxxxxxxxxxx>
---
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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