I was getting false reports about NMI lockups on CPU 3. For some reason CPU 0,1 and 2 where using apic timer, and CPU 3 was using the irq 0 timer. This patch makes the NMI watchdog count both the apic timer and the irq0 timer. Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx> Index: linux-2.6-rt-test/arch/x86_64/kernel/nmi.c =================================================================== --- linux-2.6-rt-test.orig/arch/x86_64/kernel/nmi.c +++ linux-2.6-rt-test/arch/x86_64/kernel/nmi.c @@ -938,7 +938,7 @@ int notrace __kprobes nmi_watchdog_tick( touched = 1; } - sum = read_pda(apic_timer_irqs); + sum = read_pda(apic_timer_irqs) + kstat_cpu(cpu).irqs[0]; if (__get_cpu_var(nmi_touch)) { __get_cpu_var(nmi_touch) = 0; - To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html