The new optional property "always-on" indicates that the timers are, well, always on when used with KVM. This allows for substantial performance improvement in the guest (it switches to NOHZ instead of using a periodic tick per vcpu) and removes a lot of burden from the host (no need to inject tons of interrupts with the associated rescheduling overhead). Old kernels that don't understand this property will simply ignore it. Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> --- tools/kvm/arm/timer.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/kvm/arm/timer.c b/tools/kvm/arm/timer.c index d757c1d..209251e 100644 --- a/tools/kvm/arm/timer.c +++ b/tools/kvm/arm/timer.c @@ -33,6 +33,7 @@ void timer__generate_fdt_nodes(void *fdt, struct kvm *kvm, int *irqs) _FDT(fdt_begin_node(fdt, "timer")); _FDT(fdt_property(fdt, "compatible", compatible, sizeof(compatible))); _FDT(fdt_property(fdt, "interrupts", irq_prop, sizeof(irq_prop))); + _FDT(fdt_property(fdt, "always-on", NULL, 0)); if (kvm->cfg.arch.force_cntfrq > 0) _FDT(fdt_property_cell(fdt, "clock-frequency", kvm->cfg.arch.force_cntfrq)); _FDT(fdt_end_node(fdt)); -- 1.8.3.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
