diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2007-02-16 01:27:43 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-02-16 08:13:57 -0800 |
| commit | 5d8b34fdcb384161552d01ee8f34af5ff11f9684 (patch) | |
| tree | 7052d50574d747b7ec2172051adf8126074d6982 /arch | |
| parent | 7e69f2b1ead2a4c51c12817f18263ff0e59335a6 (diff) | |
[PATCH] clocksource: Add verification (watchdog) helper
The TSC needs to be verified against another clocksource. Instead of using
hardwired assumptions of available hardware, provide a generic verification
mechanism. The verification uses the best available clocksource and handles
the usability for high resolution timers / dynticks of the clocksource which
needs to be verified.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/i386/Kconfig | 4 | ||||
| -rw-r--r-- | arch/i386/kernel/tsc.c | 49 |
2 files changed, 4 insertions, 49 deletions
diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig index 4ea31c327d1..458b3aad3eb 100644 --- a/arch/i386/Kconfig +++ b/arch/i386/Kconfig @@ -18,6 +18,10 @@ config GENERIC_TIME bool default y +config CLOCKSOURCE_WATCHDOG + bool + default y + config LOCKDEP_SUPPORT bool default y diff --git a/arch/i386/kernel/tsc.c b/arch/i386/kernel/tsc.c index b4b2be21d1c..22931d24027 100644 --- a/arch/i386/kernel/tsc.c +++ b/arch/i386/kernel/tsc.c @@ -344,49 +344,6 @@ static struct dmi_system_id __initdata bad_tsc_dmi_table[] = { {} }; -#define TSC_FREQ_CHECK_INTERVAL (10*MSEC_PER_SEC) /* 10sec in MS */ -static struct timer_list verify_tsc_freq_timer; - -/* XXX - Probably should add locking */ -static void verify_tsc_freq(unsigned long unused) -{ - static u64 last_tsc; - static unsigned long last_jiffies; - - u64 now_tsc, interval_tsc; - unsigned long now_jiffies, interval_jiffies; - - - if (check_tsc_unstable()) - return; - - rdtscll(now_tsc); - now_jiffies = jiffies; - - if (!last_jiffies) { - goto out; - } - - interval_jiffies = now_jiffies - last_jiffies; - interval_tsc = now_tsc - last_tsc; - interval_tsc *= HZ; - do_div(interval_tsc, cpu_khz*1000); - - if (interval_tsc < (interval_jiffies * 3 / 4)) { - printk("TSC appears to be running slowly. " - "Marking it as unstable\n"); - mark_tsc_unstable(); - return; - } - -out: - last_tsc = now_tsc; - last_jiffies = now_jiffies; - /* set us up to go off on the next interval: */ - mod_timer(&verify_tsc_freq_timer, - jiffies + msecs_to_jiffies(TSC_FREQ_CHECK_INTERVAL)); -} - /* * Make an educated guess if the TSC is trustworthy and synchronized * over all CPUs. @@ -424,12 +381,6 @@ static int __init init_tsc_clocksource(void) clocksource_tsc.flags &= ~CLOCK_SOURCE_IS_CONTINUOUS; } - init_timer(&verify_tsc_freq_timer); - verify_tsc_freq_timer.function = verify_tsc_freq; - verify_tsc_freq_timer.expires = - jiffies + msecs_to_jiffies(TSC_FREQ_CHECK_INTERVAL); - add_timer(&verify_tsc_freq_timer); - return clocksource_register(&clocksource_tsc); } |