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authorKoen Kooi <koen@openembedded.org>2008-06-20 12:27:02 +0000
committerKoen Kooi <koen@openembedded.org>2008-06-20 12:27:02 +0000
commitbbaf0afc9b28644b357f284ad27c9e40e015d2de (patch)
treee4bbe78f6edc0003938a07b044c5244d0f7f45c0 /packages/linux/linux-omap2-git
parent86f6fb7c542080df0d1af0f79420c9a7be82aa89 (diff)
linux omap2 git: add patch to surpress spurious timer reprogramming
Diffstat (limited to 'packages/linux/linux-omap2-git')
-rw-r--r--packages/linux/linux-omap2-git/beagleboard/timer-suppression.patch43
1 files changed, 43 insertions, 0 deletions
diff --git a/packages/linux/linux-omap2-git/beagleboard/timer-suppression.patch b/packages/linux/linux-omap2-git/beagleboard/timer-suppression.patch
new file mode 100644
index 0000000000..04362c96e3
--- /dev/null
+++ b/packages/linux/linux-omap2-git/beagleboard/timer-suppression.patch
@@ -0,0 +1,43 @@
+diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
+index b854a89..26f5569 100644
+--- a/kernel/time/tick-sched.c
++++ b/kernel/time/tick-sched.c
+@@ -253,6 +253,16 @@ void tick_nohz_stop_sched_tick(void)
+
+ /* Schedule the tick, if we are at least one jiffie off */
+ if ((long)delta_jiffies >= 1) {
++ /*
++ * calculate the expiry time for the next timer wheel
++ * timer
++ */
++ expires = ktime_add_ns(last_update, tick_period.tv64 *
++ delta_jiffies);
++
++ /* Skip reprogram of event if its not changed */
++ if(ts->tick_stopped && ktime_equal(expires, dev->next_event))
++ goto out2;
+
+ if (delta_jiffies > 1)
+ cpu_set(cpu, nohz_cpu_mask);
+@@ -304,12 +314,7 @@ void tick_nohz_stop_sched_tick(void)
+ goto out;
+ }
+
+- /*
+- * calculate the expiry time for the next timer wheel
+- * timer
+- */
+- expires = ktime_add_ns(last_update, tick_period.tv64 *
+- delta_jiffies);
++ /* Mark expiries */
+ ts->idle_expires = expires;
+
+ if (ts->nohz_mode == NOHZ_MODE_HIGHRES) {
+@@ -328,6 +333,7 @@ void tick_nohz_stop_sched_tick(void)
+ tick_do_update_jiffies64(ktime_get());
+ cpu_clear(cpu, nohz_cpu_mask);
+ }
++out2:
+ raise_softirq_irqoff(TIMER_SOFTIRQ);
+ out:
+ ts->next_jiffies = next_jiffies;