2.14. Reduce CPU Performance Spikes
The kernel command line parameter
skew_tickhelps to smooth jitter on moderate to large systems with latency-sensitive applications running. A common source of latency spikes on a realtime Linux system is when multiple CPUs contend on common locks in the Linux kernel timer tick handler. The usual locks responsible for the contention are the
xtime_lock, which is used by the timekeeping system, and the RCU (Read-Copy-Update) structure locks.
skew_tick=1boot parameter reduces contention on these kernel locks. The parameter ensures that the ticks per CPU do not occur simultaneously by making their start times 'skewed'. Skewing the start times of the per-CPU timer ticks decreases the potential for lock conflicts, reducing system jitter for interrupt response times.