From b888808093113ae7d63d213272d01fea4b8329ed Mon Sep 17 00:00:00 2001 From: Joao Martins Date: Wed, 8 Nov 2017 17:19:56 +0000 Subject: x86/xen/time: set pvclock flags on xen_time_init() Specifically check for PVCLOCK_TSC_STABLE_BIT and if this bit is set, then set it too on pvclock flags. This allows Xen clocksource to use it and thus speeding up xen_clocksource_read() callers (i.e. sched_clock()) Signed-off-by: Joao Martins Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky --- arch/x86/xen/time.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c index 244791ff8201..c96e61fd70e7 100644 --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -372,6 +372,7 @@ static const struct pv_time_ops xen_time_ops __initconst = { static void __init xen_time_init(void) { + struct pvclock_vcpu_time_info *pvti; int cpu = smp_processor_id(); struct timespec tp; @@ -395,6 +396,14 @@ static void __init xen_time_init(void) setup_force_cpu_cap(X86_FEATURE_TSC); + /* + * We check ahead on the primary time info if this + * bit is supported hence speeding up Xen clocksource. + */ + pvti = &__this_cpu_read(xen_vcpu)->time; + if (pvti->flags & PVCLOCK_TSC_STABLE_BIT) + pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT); + xen_setup_runstate_info(cpu); xen_setup_timer(cpu); xen_setup_cpu_clockevents(); -- cgit v1.2.3