From 3e51f33fcc7f55e6df25d15b55ed10c8b4da84cd Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Sat, 3 May 2008 18:29:28 +0200 Subject: 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 Signed-off-by: Ingo Molnar --- include/linux/sched.h | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'include') diff --git a/include/linux/sched.h b/include/linux/sched.h index 54c9ca26b7d..0c35b0343a7 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(): -- cgit v1.2.3