diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2011-05-20 23:14:04 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2011-05-23 13:59:54 +0200 |
| commit | 68fa61c026057a39d6ccb850aa8785043afbee02 (patch) | |
| tree | aa8a96849d4bd9b1e46c602d398cda0e72d4115c | |
| parent | hrtimers: Avoid touching inactive timer bases (diff) | |
| download | linux-68fa61c026057a39d6ccb850aa8785043afbee02.tar.xz linux-68fa61c026057a39d6ccb850aa8785043afbee02.zip | |
hrtimers: Reorder clock bases
The ordering of the clock bases is historical due to the
CLOCK_REALTIME and CLOCK_MONOTONIC constants. Now the hrtimer bases
have their own enumeration due to the gap between CLOCK_MONOTONIC and
CLOCK_BOOTTIME. So we can be more clever as most timers end up on the
CLOCK_MONOTONIC base due to the virtue of POSIX declaring that
relative CLOCK_REALTIME timers are not affected by time changes. In
desktop environments this is slowly changing as applications switch to
absolute timers, but I've observed empty CLOCK_REALTIME bases often
enough. There is no performance penalty or overhead when
CLOCK_REALTIME timers are active, but in case they are not we don't
skip over a full cache line.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Peter Zijlstra <peterz@infradead.org>
| -rw-r--r-- | include/linux/hrtimer.h | 2 | ||||
| -rw-r--r-- | kernel/hrtimer.c | 12 |
2 files changed, 7 insertions, 7 deletions
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 771c95802edc..51932e5acf7c 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -153,8 +153,8 @@ struct hrtimer_clock_base { }; enum hrtimer_base_type { - HRTIMER_BASE_REALTIME, HRTIMER_BASE_MONOTONIC, + HRTIMER_BASE_REALTIME, HRTIMER_BASE_BOOTTIME, HRTIMER_MAX_CLOCK_BASES, }; diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index 1b08f6d67f12..c541ee527ecb 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -64,18 +64,18 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) = .clock_base = { { - .index = HRTIMER_BASE_REALTIME, - .clockid = CLOCK_REALTIME, - .get_time = &ktime_get_real, - .resolution = KTIME_LOW_RES, - }, - { .index = HRTIMER_BASE_MONOTONIC, .clockid = CLOCK_MONOTONIC, .get_time = &ktime_get, .resolution = KTIME_LOW_RES, }, { + .index = HRTIMER_BASE_REALTIME, + .clockid = CLOCK_REALTIME, + .get_time = &ktime_get_real, + .resolution = KTIME_LOW_RES, + }, + { .index = HRTIMER_BASE_BOOTTIME, .clockid = CLOCK_BOOTTIME, .get_time = &ktime_get_boottime, |