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 Signed-off-by: Juergen Gross jgross@suse.com --- This is upstream commit b888808093113ae7d63d213272d01fea4b8329ed. Needed for upstream commit 867cefb4cb1012f42cada1c7d1f35ac8dd276071. --- 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 80c2a4bdf230..5687be6f5ca5 100644 --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -373,6 +373,7 @@ 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;
@@ -396,6 +397,14 @@ 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();