electron/docs/api/structures/cpu-usage.md

CPUUsage Object

• percentCPUUsage number - Percentage of CPU used since the last call to the API that returned this object. First call returns 0.
• cumulativeCPUUsage number (optional) - Total seconds of CPU time used since process startup.
• idleWakeupsPerSecond number - The number of average idle CPU wakeups per second since the last call to the API that returned this object. First call returns 0. Will always return 0 on Windows.

Both percentCPUUsage and idleWakeupsPerSecond are averages rather than instant samples, and each call starts a fresh measurement interval.

Multiple APIs return CPUUsage objects, and each tracks its own intervals:

• process.getCPUUsage() measures the process it is called in. Only calls to process.getCPUUsage() in that same process reset its interval.
• app.getAppMetrics() measures every process in the app, as the cpu property of each ProcessMetric. It keeps a separate interval for each process ID, and a single call resets all of them at once, since one call reports on every process.

Note

Each API's measurement interval is independent. Calling process.getCPUUsage() does not change what app.getAppMetrics() reports and vice-versa. The main process can therefore report different percentCPUUsage values through each API at the same moment.

Note

If one of your app's dependencies calls one of these functions, it will start a new interval before you read it. To measure an interval you control, use cumulativeCPUUsage instead. Subtract an earlier reading from a later one to get usage over that span. Reading it still means calling app.getAppMetrics() or process.getCPUUsage(), which starts a new interval for everyone else.