Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1436227

[patch 4 20/22] timer: Only wake softirq if necessary

Show all headers | View raw

With the wheel forwading in place and with the HZ=1000 4ms folding we can
avoid running the softirq at all.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/time/timer.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1608,7 +1608,18 @@ static void run_timer_softirq(struct sof
  */
 void run_local_timers(void)
 {
+	struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
+
 	hrtimer_run_queues();
+	/* Raise the softirq only if required. */
+	if (time_before(jiffies, base->clk)) {
+		if (!IS_ENABLED(CONFIG_NO_HZ_COMMON) || !base->nohz_active)
+			return;
+		/* CPU is awake, so check the deferrable base. */
+		base++;
+		if (time_before(jiffies, base->clk))
+			return;
+	}
 	raise_softirq(TIMER_SOFTIRQ);
 }
 

Back to linux.kernel | Previous | Next — Next in thread | Find similar | Unroll thread

Thread

[patch 4 20/22] timer: Only wake softirq if necessary Thomas Gleixner <tglx@linutronix.de> - 2016-07-04 12:00 +0200
  [tip:timers/core] timers: Only wake softirq if necessary tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-07-07 11:00 +0200

csiph-web