Performance counters are accessed via special file descriptors.
There's one file descriptor per virtual counter used.
-The special file descriptor is opened via the perf_event_open()
+The special file descriptor is opened via the sys_perf_event_open()
system call:
int sys_perf_event_open(struct perf_event_attr *hw_event_uptr,
If 'raw_type' is 0, then the 'type' field says what kind of counter
this is, with the following encoding:
-enum perf_event_types {
+enum perf_type_id {
PERF_TYPE_HARDWARE = 0,
PERF_TYPE_SOFTWARE = 1,
PERF_TYPE_TRACEPOINT = 2,
* Generalized performance counter event types, used by the hw_event.event_id
* parameter of the sys_perf_event_open() syscall:
*/
-enum hw_event_ids {
+enum perf_hw_id {
/*
* Common hardware events, generalized by the kernel:
*/
* physical and sw events of the kernel (and allow the profiling of them as
* well):
*/
-enum sw_event_ids {
+enum perf_sw_ids {
PERF_COUNT_SW_CPU_CLOCK = 0,
PERF_COUNT_SW_TASK_CLOCK = 1,
PERF_COUNT_SW_PAGE_FAULTS = 2,
The 'comm' bit allows tracking of process comm data on process creation.
This too is recorded in the ring-buffer (see below).
-The 'pid' parameter to the perf_event_open() system call allows the
+The 'pid' parameter to the sys_perf_event_open() system call allows the
counter to be specific to a task:
pid == 0: if the pid parameter is zero, the counter is attached to the
The 'group_fd' parameter allows counter "groups" to be set up. A
counter group has one counter which is the group "leader". The leader
-is created first, with group_fd = -1 in the perf_event_open call
+is created first, with group_fd = -1 in the sys_perf_event_open call
that creates it. The rest of the group members are created
subsequently, with group_fd giving the fd of the group leader.
(A single counter on its own is created with group_fd = -1 and is