See chapters 18,19 of the Intel Architecture Software Developer's Manual.
See chapter D5 of the ARM64 Architecture Reference Manual and chapter 12 of the Cortex A53 Technical Reference Manual.
Several ioctls are provided to control performance data collection.
ssize_t ioctl_perfmon_get_properties(int fd, perfmon_ioctl_properties_t* props);
Return various aspects of PMU properties in |*props|.
Returns 0 on success or a negative error code.
ssize_t ioctl_perfmon_alloc_trace(int fd, const ioctl_perfmon_alloc_t* alloc);
Allocate various resources needed to perform a trace. This must be called before staging a configuration and starting a trace. This must be called while tracing is stopped.
Returns 0 on success or a negative error code.
ssize_t ioctl_perfmon_free_trace(int fd);
Free all resources allocated by a preceding all to ioctl_perfmon_alloc_trace(). This must be called while tracing is stopped.
Returns 0 on success or a negative error code.
ssize_t ioctl_perfmon_get_alloc(int fd, perfmon_alloc_t* alloc);
Fetch the trace configuration passed in to a preceding call to ioctl_perfmon_alloc_trace().
Returns 0 on success or a negative error code.
ssize_t ioctl_perfmon_stage_config(int fd, const perfmon_ioctl_config_t* config);
Configure data collection. |*config| specifies the events to collect and the rate at which to collect them. This must be called while tracing is stopped.
Returns 0 on success or a negative error code.
ssize_t ioctl_perfmon_get_config(int fd, perfmon_ioctl_config_t* config);
Fetch the configuration passed in to a preceding call to ioctl_perfmon_stage_config().
Returns 0 on success or a negative error code.
ssize_t ioctl_perfmon_get_buffer_handle(
int fd, const ioctl_perfmon_buffer_handle_req_t* rqst,
zx_handle_t* handle);
Fetch the handle of the VMO for the given descriptor. Each CPU is given a separate VMO and the descriptor is the cpu's number. This must be called while tracing is stopped.
Returns 0 on success or a negative error code.
ssize_t ioctl_perfmon_start(int fd);
Start data collection. This must be called while tracing is stopped.
Returns 0 on success or a negative error code.
ssize_t ioctl_perfmon_stop(int fd);
Stop tracing and collect any remaining data from each cpu. This may be called even if tracing is already stopped.
Returns 0 on success or a negative error code.
Here's a sketch of typical usage: