The periodic kvmclock sync can be an undesired source of latencies.
Signed-off-by: Marcelo Tosatti <[email protected]>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0033df3..be56fd3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -98,6 +98,9 @@ module_param(ignore_msrs, bool, S_IRUGO | S_IWUSR);
unsigned int min_timer_period_us = 500;
module_param(min_timer_period_us, uint, S_IRUGO | S_IWUSR);
+static bool kvmclock_periodic_sync = 1;
+module_param(kvmclock_periodic_sync, bool, S_IRUGO | S_IWUSR);
+
bool kvm_has_tsc_control;
EXPORT_SYMBOL_GPL(kvm_has_tsc_control);
u32 kvm_max_guest_tsc_khz;
@@ -1718,7 +1721,8 @@ static void kvmclock_sync_fn(struct work_struct *work)
struct kvm *kvm = container_of(ka, struct kvm, arch);
schedule_delayed_work(&kvm->arch.kvmclock_update_work, 0);
- schedule_delayed_work(&kvm->arch.kvmclock_sync_work,
+ if (kvmclock_periodic_sync)
+ schedule_delayed_work(&kvm->arch.kvmclock_sync_work,
KVMCLOCK_SYNC_PERIOD);
}
@@ -6971,7 +6975,8 @@ int kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
kvm_write_tsc(vcpu, &msr);
vcpu_put(vcpu);
- schedule_delayed_work(&kvm->arch.kvmclock_sync_work,
+ if (kvmclock_periodic_sync)
+ schedule_delayed_work(&kvm->arch.kvmclock_sync_work,
KVMCLOCK_SYNC_PERIOD);
return r;
--
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