diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2008-05-03 18:29:28 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-05-05 23:56:18 +0200 |
| commit | 3e51f33fcc7f55e6df25d15b55ed10c8b4da84cd (patch) | |
| tree | 3752f9ea8e014ec40e95a1b197b0a3d18e1056a8 /include/linux | |
| parent | a5574cf65b5f03ce9ade3918764fe22e5e2371e3 (diff) | |
sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
this replaces the rq->clock stuff (and possibly cpu_clock()).
- architectures that have an 'imperfect' hardware clock can set
CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
- the 'jiffie' window might be superfulous when we update tick_gtod
before the __update_sched_clock() call in sched_clock_tick()
- cpu_clock() might be implemented as:
sched_clock_cpu(smp_processor_id())
if the accuracy proves good enough - how far can TSC drift in a
single jiffie when considering the filtering and idle hooks?
[ mingo@elte.hu: various fixes and cleanups ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/sched.h | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 54c9ca26b7d8..0c35b0343a76 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1553,6 +1553,35 @@ static inline int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask) extern unsigned long long sched_clock(void); +#ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK +static inline void sched_clock_init(void) +{ +} + +static inline u64 sched_clock_cpu(int cpu) +{ + return sched_clock(); +} + +static inline void sched_clock_tick(void) +{ +} + +static inline void sched_clock_idle_sleep_event(void) +{ +} + +static inline void sched_clock_idle_wakeup_event(u64 delta_ns) +{ +} +#else +extern void sched_clock_init(void); +extern u64 sched_clock_cpu(int cpu); +extern void sched_clock_tick(void); +extern void sched_clock_idle_sleep_event(void); +extern void sched_clock_idle_wakeup_event(u64 delta_ns); +#endif + /* * For kernel-internal use: high-speed (but slightly incorrect) per-cpu * clock constructed from sched_clock(): |