CPU Usage precise cho biết how much CPU time each thread consumes, and what the call stack looked like when a thread lost or gained the CPU. CPU Usage sampled cho biết what a thread is doing between context switches

This table is labeled CPU Usage (Precise) to distinguish it from the CPU Usage (Sampled) data. The sampled data comes from interrupting the CPU frequently – sampling – and seeing what it is doing. The precise data that is discussed here comes from instrumenting the context switch code in the kernel. Every time a thread starts or stops running the precise time of this activity is recorded, with optional call stacks. This means that the CPU Usage (Precise) data can tell exactly how much CPU time each thread consumes, and what the call stack looked like when a thread lost/gained the CPU. However the CPU Usage (Precise) data can’t tell you what a thread is doing between context switches – that is the job of the CPU Usage (Sampled) data. Understanding this difference is crucial.

Nguồn:: The Lost Xperf Documentation–CPU Usage (Precise) | Random ASCII – tech blog of Bruce Dawson