x86/xen/time: set pvclock flags on xen_time_init() (b8888080) · Commits · 戴 / test

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 <joao.m.martins@oracle.com> Reviewed-by:

Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by:

Boris Ostrovsky <boris.ostrovsky@oracle.com>

arch/x86/xen/time.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -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();

Admin message