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-rw-r--r--arch/x86/kernel/tsc.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 3e1c057..ef4dac5 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -589,22 +589,26 @@ EXPORT_SYMBOL(recalibrate_cpu_khz);
*/
DEFINE_PER_CPU(unsigned long, cyc2ns);
+DEFINE_PER_CPU(unsigned long long, cyc2ns_offset);
static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu)
{
- unsigned long long tsc_now, ns_now;
+ unsigned long long tsc_now, ns_now, *offset;
unsigned long flags, *scale;
local_irq_save(flags);
sched_clock_idle_sleep_event();
scale = &per_cpu(cyc2ns, cpu);
+ offset = &per_cpu(cyc2ns_offset, cpu);
rdtscll(tsc_now);
ns_now = __cycles_2_ns(tsc_now);
- if (cpu_khz)
+ if (cpu_khz) {
*scale = (NSEC_PER_MSEC << CYC2NS_SCALE_FACTOR)/cpu_khz;
+ *offset = ns_now - (tsc_now * *scale >> CYC2NS_SCALE_FACTOR);
+ }
sched_clock_idle_wakeup_event(0);
local_irq_restore(flags);
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