unsigned long ring_buffer_entries(struct ring_buffer *buffer);
unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
+unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
+unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
u64 ring_buffer_time_stamp(int cpu);
void ring_buffer_normalize_time_stamp(int cpu, u64 *ts);