The patch titled
high-res timers: utilize TSC clocksource again
has been added to the -mm tree. Its filename is
high-res-timers-utilize-tsc-clocksource-again.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: high-res timers: utilize TSC clocksource again
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Utilize the TSC clocksource again on high-res timers. (dependent on the
existence of pmtimer as a fallback to resync across TSC-destructive
resume/halt/cpufreq events, but that is normally available.)
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/i386/kernel/tsc.c | 50 ++++++++++++++++++++++++---------------
1 file changed, 31 insertions(+), 19 deletions(-)
diff -puN arch/i386/kernel/tsc.c~high-res-timers-utilize-tsc-clocksource-again arch/i386/kernel/tsc.c
--- a/arch/i386/kernel/tsc.c~high-res-timers-utilize-tsc-clocksource-again
+++ a/arch/i386/kernel/tsc.c
@@ -10,6 +10,7 @@
#include <linux/jiffies.h>
#include <linux/init.h>
#include <linux/dmi.h>
+#include <linux/acpi_pmtmr.h>
#include <asm/delay.h>
#include <asm/tsc.h>
@@ -388,42 +389,51 @@ static struct dmi_system_id __initdata b
#define TSC_FREQ_CHECK_INTERVAL (10*MSEC_PER_SEC) /* 10sec in MS */
static struct timer_list verify_tsc_freq_timer;
+static unsigned long pm_multiplier;
/* XXX - Probably should add locking */
static void verify_tsc_freq(unsigned long unused)
{
static u64 last_tsc;
- static unsigned long last_jiffies;
+ static unsigned long last_jiffies, last_pm;
u64 now_tsc, interval_tsc;
- unsigned long now_jiffies, interval_jiffies;
-
+ unsigned long now_jiffies, interval_jiffies, pm, pm_delta;
if (check_tsc_unstable())
return;
rdtscll(now_tsc);
now_jiffies = jiffies;
+ pm = acpi_pm_read_early();
- if (!last_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 (pm == last_pm) {
+ interval_tsc = now_tsc - last_tsc;
+ interval_tsc *= HZ;
+ do_div(interval_tsc, cpu_khz*1000);
+ } else {
+ if (pm < last_pm)
+ pm += ACPI_PM_OVRRUN;
+ pm_delta = pm - last_pm;
+ interval_tsc = (((u64) pm_delta) * pm_multiplier) >> 22;
+ do_div(interval_tsc, TICK_NSEC);
+ }
if (interval_tsc < (interval_jiffies * 3 / 4)) {
printk("TSC appears to be running slowly. "
- "Marking it as unstable\n");
+ "Marking it as unstable\n");
mark_tsc_unstable();
return;
}
-
out:
last_tsc = now_tsc;
last_jiffies = now_jiffies;
+ last_pm = pm;
/* set us up to go off on the next interval: */
mod_timer(&verify_tsc_freq_timer,
jiffies + msecs_to_jiffies(TSC_FREQ_CHECK_INTERVAL));
@@ -460,23 +470,25 @@ static int __init init_tsc_clocksource(v
current_tsc_khz = tsc_khz;
clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
clocksource_tsc.shift);
-#ifndef CONFIG_HIGH_RES_TIMERS
/* lower the rating if we already know its unstable: */
if (check_tsc_unstable())
clocksource_tsc.rating = 0;
-#else
+
/*
- * Mark TSC unsuitable for high resolution timers. TSC has so
- * many pitfalls: frequency changes, stop in idle ... When we
+ * Mark TSC unsuitable for high resolution timers, when
+ * pm_timer is not available as a fallback. TSC has so many
+ * pitfalls: frequency changes, stop in idle ... When we
* switch to high resolution mode we can not longer detect a
* firmware caused frequency change, as the emulated tick uses
* TSC as reference. This results in a circular dependency.
- * Switch only to high resolution mode, if pm_timer or such
- * is available.
+ * Switch only to high resolution mode, if pm_timer or such is
+ * available.
*/
- clocksource_tsc.rating = 50;
- clocksource_tsc.is_continuous = 0;
-#endif
+ if (!pmtmr_ioport || !clocksource_tsc.rating)
+ clocksource_tsc.is_continuous = 0;
+
+ pm_multiplier = clocksource_hz2mult(PMTMR_TICKS_PER_SEC, 22);
+
init_timer(&verify_tsc_freq_timer);
verify_tsc_freq_timer.function = verify_tsc_freq;
verify_tsc_freq_timer.expires =
_
Patches currently in -mm which might be from tglx@xxxxxxxxxxxxx are
git-mtd.patch
ktime-fix-signed--unsigned-mismatch-in-ktime_to_ns.patch
gtod-exponential-update_wall_time.patch
gtod-persistent-clock-support-core.patch
gtod-persistent-clock-support-i386.patch
gtod-persistent-clock-support-i386-i386-unexport-read_persistent_clock.patch
time-uninline-jiffiesh.patch
time-uninline-jiffiesh-fix.patch
time-fix-msecs_to_jiffies-bug.patch
time-fix-timeout-overflow.patch
cleanup-uninline-irq_enter-and-move-it-into-a-function.patch
dynticks-extend-next_timer_interrupt-to-use-a-reference-jiffie.patch
dynticks-extend-next_timer_interrupt-to-use-a-reference-jiffie-remove-incorrect-warning-in-kernel-timerc.patch
hrtimers-namespace-and-enum-cleanup.patch
hrtimers-clean-up-locking.patch
updated-hrtimers-state-tracking.patch
updated-hrtimers-clean-up-callback-tracking.patch
updated-hrtimers-move-and-add-documentation.patch
updated-add-a-framework-to-manage-clock-event-devices.patch
updated-acpi-include-apich.patch
updated-acpi-keep-track-of-timer-broadcast.patch
updated-acpi-add-state-propagation-for-dynamic-broadcasting.patch
updated-i386-cleanup-apic-code.patch
updated-i386-convert-to-clock-event-devices.patch
updated-i386-convert-to-clock-event-devices-fix.patch
updated-i386-convert-to-clock-event-devices-arch-i386-kernel-apicc-make-a-function-static.patch
updated-i386-convert-to-clock-event-devices-remove-arch-i386-kernel-time_hpetchpet_reenable.patch
updated-pm_timer-allow-early-access-and-move-externs-to-a-header-file.patch
updated-i386-rework-local-apic-calibration.patch
updated-high-res-timers-core.patch
updated-gtod-mark-tsc-unusable-for-highres-timers.patch
high-res-timers-utilize-tsc-clocksource-again.patch
updated-dynticks-core-code.patch
updated-dyntick-add-nohz-stats-to-proc-stat.patch
updated-dynticks-i386-arch-code.patch
updated-dynticks-fix-nmi-watchdog.patch
updated-high-res-timers-dynticks-enable-i386-support.patch
updated-debugging-feature-timer-stats.patch
clockevents-core-check-for-clock-event-device-handler-being-non-null-before-calling-it.patch
round_jiffies-infrastructure.patch
round_jiffies-infrastructure-fix.patch
clocksource-add-usage-of-config_sysfs.patch
clocksource-small-cleanup-2.patch
clocksource-small-cleanup-2-fix.patch
clocksource-small-acpi_pm-cleanup.patch
-
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