Performance events

Perf metrics count the rate of one or more performance events that occur in a program. There are some software events that the Linux kernel provides, but most are hardware events tracked by the Performance Monitoring Unit (PMU) of the CPU. Generalized hardware events are event name aliases that the Linux kernel identifies.

The quantity and combinations (in some cases) of events that can be simultaneously tracked is limited by the hardware. This feature does not support multiplexing performance events.

If the set of events you requested cannot be tracked at the same time, Linaro MAP ends the profiling session immediately with an error message. Try requesting fewer events, or a different combination. See the PMU reference manual for your architecture for more information on incompatible events.