The patch titled
hrtimer: reduce calls to hrtimer_get_softirq_time()
has been removed from the -mm tree. Its filename was
hrtimer-reduce-calls-to-hrtimer_get_softirq_time.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: hrtimer: reduce calls to hrtimer_get_softirq_time()
From: Dimitri Sivanich <sivanich@xxxxxxx>
It seems that hrtimer_run_queues() is calling hrtimer_get_softirq_time() more
often than it needs to. This can cause frequent contention on systems with
large numbers of processors/cores.
With this patch, hrtimer_run_queues only calls hrtimer_get_softirq_time() if
there is a pending timer in one of the hrtimer bases, and only once.
This also combines hrtimer_run_queues() and the inline run_hrtimer_queue()
into one function.
Signed-off-by: Dimitri Sivanich <sivanich@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/hrtimer.c | 65 ++++++++++++++++++++++-----------------------
1 file changed, 33 insertions(+), 32 deletions(-)
diff -puN kernel/hrtimer.c~hrtimer-reduce-calls-to-hrtimer_get_softirq_time kernel/hrtimer.c
--- a/kernel/hrtimer.c~hrtimer-reduce-calls-to-hrtimer_get_softirq_time
+++ a/kernel/hrtimer.c
@@ -1238,51 +1238,52 @@ void hrtimer_run_pending(void)
/*
* Called from hardirq context every jiffy
*/
-static inline void run_hrtimer_queue(struct hrtimer_cpu_base *cpu_base,
- int index)
+void hrtimer_run_queues(void)
{
struct rb_node *node;
- struct hrtimer_clock_base *base = &cpu_base->clock_base[index];
+ struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
+ struct hrtimer_clock_base *base;
+ int index;
+ int gst = 1;
- if (!base->first)
+ if (hrtimer_hres_active())
return;
- if (base->get_softirq_time)
- base->softirq_time = base->get_softirq_time();
+ for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
+ base = &cpu_base->clock_base[index];
- spin_lock(&cpu_base->lock);
-
- while ((node = base->first)) {
- struct hrtimer *timer;
-
- timer = rb_entry(node, struct hrtimer, node);
- if (base->softirq_time.tv64 <= timer->expires.tv64)
- break;
-
- if (timer->cb_mode == HRTIMER_CB_SOFTIRQ) {
- __remove_hrtimer(timer, base, HRTIMER_STATE_PENDING, 0);
- list_add_tail(&timer->cb_entry,
- &base->cpu_base->cb_pending);
+ if (!base->first)
continue;
+
+ if (gst) {
+ hrtimer_get_softirq_time(cpu_base);
+ gst = 0;
}
- __run_hrtimer(timer);
- }
- spin_unlock(&cpu_base->lock);
-}
+ if (base->get_softirq_time)
+ base->softirq_time = base->get_softirq_time();
-void hrtimer_run_queues(void)
-{
- struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
- int i;
+ spin_lock(&cpu_base->lock);
- if (hrtimer_hres_active())
- return;
+ while ((node = base->first)) {
+ struct hrtimer *timer;
- hrtimer_get_softirq_time(cpu_base);
+ timer = rb_entry(node, struct hrtimer, node);
+ if (base->softirq_time.tv64 <= timer->expires.tv64)
+ break;
+
+ if (timer->cb_mode == HRTIMER_CB_SOFTIRQ) {
+ __remove_hrtimer(timer, base,
+ HRTIMER_STATE_PENDING, 0);
+ list_add_tail(&timer->cb_entry,
+ &base->cpu_base->cb_pending);
+ continue;
+ }
- for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
- run_hrtimer_queue(cpu_base, i);
+ __run_hrtimer(timer);
+ }
+ spin_unlock(&cpu_base->lock);
+ }
}
/*
_
Patches currently in -mm which might be from sivanich@xxxxxxx are
origin.patch
git-hrt.patch
sgi-altix-mmtimer-allow-larger-number-of-timers-per-node.patch
sgi-altix-mmtimer-allow-larger-number-of-timers-per-node-fix.patch
sgi-altix-mmtimer-allow-larger-number-of-timers-per-node-fix-2.patch
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