This read-only integer reports the number of interval-timer ticks all CPUs spent in mpsynch mode, meaning Kernel mode on the kernel or interrupt stack with an active spinlock busy wait, during the last one-minute interval. An administrator watches it for signs of multiprocessor lock contention degrading performance. For example, a high sSpinOne value on a multi-CPU system points the admin toward spinlock contention as a possible cause of poor scaling across CPUs.