From aa7b630ea023d2d70b34af18cea92f31429c1db0 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 21 Apr 2017 11:32:46 +0200
Subject: [PATCH] x86/tsc: Feed refined TSC calibration into sched_clock()
Git-commit: aa7b630ea023d2d70b34af18cea92f31429c1db0
Patch-mainline: v4.13-rc1
References: bsc#1052904

For the (older) CPUs that still need the refined TSC calibration, also
update the sched_clock() rate.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>

---
 arch/x86/kernel/tsc.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index dda964c6387d..66015195bd18 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1161,6 +1161,7 @@ static void tsc_refine_calibration_work(struct work_struct *work)
 	static int hpet;
 	u64 tsc_stop, ref_stop, delta;
 	unsigned long freq;
+	int cpu;
 
 	/* Don't bother refining TSC on unstable systems */
 	if (check_tsc_unstable())
@@ -1211,6 +1212,10 @@ static void tsc_refine_calibration_work(struct work_struct *work)
 	/* Inform the TSC deadline clockevent devices about the recalibration */
 	lapic_update_tsc_freq();
 
+	/* Update the sched_clock() rate to match the clocksource one */
+	for_each_possible_cpu(cpu)
+		__set_cyc2ns_scale(tsc_khz, cpu, tsc_stop);
+
 out:
 	if (boot_cpu_has(X86_FEATURE_ART))
 		art_related_clocksource = &clocksource_tsc;
-- 
2.12.0