-
Leo Yan authored
CPU is active when have running tasks on it and CPUFreq governor can select different operating points (OPP) according to different workload; we use 'pstate' to present CPU state which have running tasks with one specific OPP. On the other hand, CPU is idle which only idle task on it, CPUIdle governor can select one specific idle state to power off hardware logics; we use 'cstate' to present CPU idle state. Based on trace events 'cpu_idle' and 'cpu_frequency' we can accomplish the duration statistics for every state. Every time when CPU enters into or exits from idle states, the trace event 'cpu_idle' is recorded; trace event 'cpu_frequency' records the event for CPU OPP changing, so it's easily to know how long time the CPU stays in the specified OPP, and the CPU must be not in any idle state. This patch is to utilize the mentioned trace events for pstate and cstate statistics. To achieve more accurate profiling data, the program uses below sequence ...
c5350777