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| author | Nicolai Stange <nicstange@gmail.com> | 2016-07-14 17:22:55 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-08-10 12:38:12 +0200 |
| commit | 6731b0d611a1274f9e785fa0189ac2aeeabd0591 (patch) | |
| tree | fe49e0716114a5160de030440eb9e2c3635e6d57 /arch/x86/kernel/tsc.c | |
| parent | 1a9e4c564ab174e53ed86def922804a5ddc63e7d (diff) | |
| download | op-kernel-dev-6731b0d611a1274f9e785fa0189ac2aeeabd0591.zip op-kernel-dev-6731b0d611a1274f9e785fa0189ac2aeeabd0591.tar.gz | |
x86/timers/apic: Inform TSC deadline clockevent device about recalibration
This patch eliminates a source of imprecise APIC timer interrupts,
which imprecision may result in double interrupts or even late
interrupts.
The TSC deadline clockevent devices' configuration and registration
happens before the TSC frequency calibration is refined in
tsc_refine_calibration_work().
This results in the TSC clocksource and the TSC deadline clockevent
devices being configured with slightly different frequencies: the former
gets the refined one and the latter are configured with the inaccurate
frequency detected earlier by means of the "Fast TSC calibration using PIT".
Within the APIC code, introduce the notifier function
lapic_update_tsc_freq() which reconfigures all per-CPU TSC deadline
clockevent devices with the current tsc_khz.
Call it from the TSC code after TSC calibration refinement has happened.
Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Christopher S. Hall <christopher.s.hall@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Link: http://lkml.kernel.org/r/20160714152255.18295-3-nicstange@gmail.com
[ Pushed #ifdef CONFIG_X86_LOCAL_APIC into header, improved changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/tsc.c')
| -rw-r--r-- | arch/x86/kernel/tsc.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index a804b5a..8fb4b6a 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -22,6 +22,7 @@ #include <asm/nmi.h> #include <asm/x86_init.h> #include <asm/geode.h> +#include <asm/apic.h> unsigned int __read_mostly cpu_khz; /* TSC clocks / usec, not used here */ EXPORT_SYMBOL(cpu_khz); @@ -1249,6 +1250,9 @@ static void tsc_refine_calibration_work(struct work_struct *work) (unsigned long)tsc_khz / 1000, (unsigned long)tsc_khz % 1000); + /* Inform the TSC deadline clockevent devices about the recalibration */ + lapic_update_tsc_freq(); + out: if (boot_cpu_has(X86_FEATURE_ART)) art_related_clocksource = &clocksource_tsc; |
