Like profile- n probes, tick- n probes fire every fixed interval at high interrupt level. However, unlike profile- n probes, which fire on every CPU, tick- n probes fire on only one CPU per interval. The actual CPU may change over time. As with profile- n probes, n defaults to rate-per-second but may also have an optional time suffix. tick- n probes have several uses, such as provideing some periodic output or taking a periodic action.