GitHub-Mirror/linux-bl808
2
0
Fork 0
mirror of https://github.com/Fishwaldo/linux-bl808.git synced 2025-06-17 20:25:19 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

sched: x86, track TSC-unstable events

Browse source 
track TSC-unstable events and propagate it to the scheduler code.
Also allow sched_clock() to be used when the TSC is unstable,
the rq_clock() wrapper creates a reliable clock out of it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2007-07-09 18:51:59 +02:00
parent dd41f596cd
commit bb29ab2686
3 changed files with 17 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

9
arch/i386/kernel/tsc.c
View file

@ -4,6 +4,7 @@
* See comments there for proper credits. * See comments there for proper credits.
*/ */
#include <linux/sched.h>
#include <linux/clocksource.h> #include <linux/clocksource.h>
#include <linux/workqueue.h> #include <linux/workqueue.h>
#include <linux/cpufreq.h> #include <linux/cpufreq.h>
@ -106,8 +107,13 @@ unsigned long long sched_clock(void)
/* /*
* Fall back to jiffies if there's no TSC available: * Fall back to jiffies if there's no TSC available:
* ( But note that we still use it if the TSC is marked
* unstable. We do this because unlike Time Of Day,
* the scheduler clock tolerates small errors and it's
* very important for it to be as fast as the platform
* can achive it. )
*/ */
if (unlikely(!tsc_enabled)) if (unlikely(!tsc_enabled && !tsc_unstable))
/* No locking but a rare wrong value is not a big deal: */ /* No locking but a rare wrong value is not a big deal: */
return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ); return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ);
@ -277,6 +283,7 @@ static struct clocksource clocksource_tsc = {
void mark_tsc_unstable(char *reason) void mark_tsc_unstable(char *reason)
{ {
sched_clock_unstable_event();
if (!tsc_unstable) { if (!tsc_unstable) {
tsc_unstable = 1; tsc_unstable = 1;
tsc_enabled = 0; tsc_enabled = 0;

2
include/linux/sched.h
View file

@ -1321,6 +1321,8 @@ extern void sched_exec(void);
#define sched_exec() {} #define sched_exec() {}
#endif #endif
extern void sched_clock_unstable_event(void);
#ifdef CONFIG_HOTPLUG_CPU #ifdef CONFIG_HOTPLUG_CPU
extern void idle_task_exit(void); extern void idle_task_exit(void);
#else #else

7
kernel/sched.c
View file

@ -67,6 +67,13 @@ unsigned long long __attribute__((weak)) sched_clock(void)
return (unsigned long long)jiffies * (1000000000 / HZ); return (unsigned long long)jiffies * (1000000000 / HZ);
} }
/*
* CPU frequency is/was unstable - start new by setting prev_clock_raw:
*/
void sched_clock_unstable_event(void)
{
}
/* /*
* Convert user-nice values [ -20 ... 0 ... 19 ] * Convert user-nice values [ -20 ... 0 ... 19 ]
* to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ], * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],