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authorIngo Molnar <mingo@elte.hu>2007-08-23 09:18:02 -0400
committerIngo Molnar <mingo@elte.hu>2007-08-23 09:18:02 -0400
commit2aa44d0567ed21b47b87d68819415d48194cb923 (patch)
tree7be2a8a30a23b363e1e2aecd41934e75f581e115 /include/linux
parentb377fd3982ad957c796758a90e2988401a884241 (diff)
sched: sched_clock_idle_[sleep|wakeup]_event()
construct a more or less wall-clock time out of sched_clock(), by using ACPI-idle's existing knowledge about how much time we spent idling. This allows the rq clock to work around TSC-stops-in-C2, TSC-gets-corrupted-in-C3 type of problems. ( Besides the scheduler's statistics this also benefits blktrace and printk-timestamps as well. ) Furthermore, the precise before-C2/C3-sleep and after-C2/C3-wakeup callbacks allow the scheduler to get out the most of the period where the CPU has a reliable TSC. This results in slightly more precise task statistics. the ACPI bits were acked by Len. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/sched.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 682ef87da6eb..1845b2e99a87 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1388,7 +1388,8 @@ extern void sched_exec(void);
1388#define sched_exec() {} 1388#define sched_exec() {}
1389#endif 1389#endif
1390 1390
1391extern void sched_clock_unstable_event(void); 1391extern void sched_clock_idle_sleep_event(void);
1392extern void sched_clock_idle_wakeup_event(u64 delta_ns);
1392 1393
1393#ifdef CONFIG_HOTPLUG_CPU 1394#ifdef CONFIG_HOTPLUG_CPU
1394extern void idle_task_exit(void); 1395extern void idle_task_exit(void);