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authorThomas Gleixner <tglx@linutronix.de>2006-03-26 01:38:05 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-26 08:57:02 -0800
commit92127c7a45d4d167d9b015a5f9de6b41ed66f1d0 (patch)
tree4742cc36ff0b26c999365d1e84133886bb694096 /kernel/hrtimer.c
parenta0e9285233a32edf267d27cd03fe0056951422cf (diff)
downloadlinux-92127c7a45d4d167d9b015a5f9de6b41ed66f1d0.tar.bz2
[PATCH] hrtimers: optimize softirq runqueues
The hrtimer softirq is called from the timer softirq every tick. Retrieve the current time from xtime and wall_to_monotonic instead of calling base->get_time() for each timer base. Store the time in the base structure and provide a hook once clock source abstractions are in place and to keep the code open for new base clocks. Based on a patch from: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/hrtimer.c')
-rw-r--r--kernel/hrtimer.c28
1 files changed, 26 insertions, 2 deletions
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 14bc9cfa6399..b728cc53452b 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -123,6 +123,26 @@ void ktime_get_ts(struct timespec *ts)
EXPORT_SYMBOL_GPL(ktime_get_ts);
/*
+ * Get the coarse grained time at the softirq based on xtime and
+ * wall_to_monotonic.
+ */
+static void hrtimer_get_softirq_time(struct hrtimer_base *base)
+{
+ ktime_t xtim, tomono;
+ unsigned long seq;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+ xtim = timespec_to_ktime(xtime);
+ tomono = timespec_to_ktime(wall_to_monotonic);
+
+ } while (read_seqretry(&xtime_lock, seq));
+
+ base[CLOCK_REALTIME].softirq_time = xtim;
+ base[CLOCK_MONOTONIC].softirq_time = ktime_add(xtim, tomono);
+}
+
+/*
* Functions and macros which are different for UP/SMP systems are kept in a
* single place
*/
@@ -586,9 +606,11 @@ int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
*/
static inline void run_hrtimer_queue(struct hrtimer_base *base)
{
- ktime_t now = base->get_time();
struct rb_node *node;
+ if (base->get_softirq_time)
+ base->softirq_time = base->get_softirq_time();
+
spin_lock_irq(&base->lock);
while ((node = base->first)) {
@@ -598,7 +620,7 @@ static inline void run_hrtimer_queue(struct hrtimer_base *base)
void *data;
timer = rb_entry(node, struct hrtimer, node);
- if (now.tv64 <= timer->expires.tv64)
+ if (base->softirq_time.tv64 <= timer->expires.tv64)
break;
fn = timer->function;
@@ -641,6 +663,8 @@ void hrtimer_run_queues(void)
struct hrtimer_base *base = __get_cpu_var(hrtimer_bases);
int i;
+ hrtimer_get_softirq_time(base);
+
for (i = 0; i < MAX_HRTIMER_BASES; i++)
run_hrtimer_queue(&base[i]);
}