Cache reference, mutex lock/unlock, disk seek, etc...

SmokePing is a deluxe latency measurement tool. It can measure, store and display latency, latency distribution and packet loss. SmokePing uses RRDtool to maintain a longterm data-store and to draw pretty graphs, giving up to the minute information on the state of each network connection.

These are some examples of using the perf Linux profiler, which has also been called Performance Counters for Linux (PCL), Linux perf events (LPE), or perf_events. Like Vince Weaver, I'll call it perf_events so that you can search on that term later.

Timechart is a tool, based on 'perf', that has the objective to show on a system level what is going on, at various levels of detail, with the Linux system performance.

The metric we all use for CPU utilization is deeply misleading, and getting worse every year. What is CPU utilization? How busy your processors are? No, that's not what it measures. Yes, I'm talking about the "%CPU" metric used everywhere, by everyone. In every performance monitoring product.

netdata is a scalable, distributed, real-time, performance and health monitoring solution for Linux, FreeBSD and MacOS. It is open-source too.