linux-kernel - [PATCH] clocksource/drivers/tegra: allow timer irq affinity change

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Date:	Sun, 25 Oct 2015 16:40:30 +0100
From:	Lucas Stach <dev@...xeye.de>
To:	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Thomas Gleixner <tglx@...utronix.de>
Cc:	Stephen Warren <swarren@...dotorg.org>,
	Thierry Reding <thierry.reding@...il.com>,
	Alexandre Courbot <gnurou@...il.com>,
	linux-kernel@...r.kernel.org, linux-tegra@...r.kernel.org
Subject: [PATCH] clocksource/drivers/tegra: allow timer irq affinity change

Allow the timer core to change the smp affinity of the broadcast timer
irq by setting CLOCK_EVT_FEAT_DYNIRQ flag.

This reduces interrupt pressure and wakeups on CPU0 as well as vastly
reducing the number of timer broadcast IPIs.

Signed-off-by: Lucas Stach <dev@...xeye.de>
---
 drivers/clocksource/tegra20_timer.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/clocksource/tegra20_timer.c b/drivers/clocksource/tegra20_timer.c
index 6ebda11..38333ab 100644
--- a/drivers/clocksource/tegra20_timer.c
+++ b/drivers/clocksource/tegra20_timer.c
@@ -96,7 +96,8 @@ static struct clock_event_device tegra_clockevent = {
 	.name			= "timer0",
 	.rating			= 300,
 	.features		= CLOCK_EVT_FEAT_ONESHOT |
-				  CLOCK_EVT_FEAT_PERIODIC,
+				  CLOCK_EVT_FEAT_PERIODIC |
+				  CLOCK_EVT_FEAT_DYNIRQ,
 	.set_next_event		= tegra_timer_set_next_event,
 	.set_state_shutdown	= tegra_timer_shutdown,
 	.set_state_periodic	= tegra_timer_set_periodic,
-- 
2.4.3

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