diff --git a/Documentation/perf_counter/perf.h b/Documentation/perf_counter/perf.h
new file mode 100644
index 0000000..391fcc7
--- /dev/null
+++ b/Documentation/perf_counter/perf.h
@@ -0,0 +1,64 @@
+#ifndef _PERF_PERF_H
+#define _PERF_PERF_H
+
+/*
+ * prctl(PR_TASK_PERF_COUNTERS_DISABLE) will (cheaply) disable all
+ * counters in the current task.
+ */
+#define PR_TASK_PERF_COUNTERS_DISABLE   31
+#define PR_TASK_PERF_COUNTERS_ENABLE    32
+
+#define rdclock()					\
+({							\
+	struct timespec ts;				\
+							\
+	clock_gettime(CLOCK_MONOTONIC, &ts);		\
+	ts.tv_sec * 1000000000ULL + ts.tv_nsec;		\
+})
+
+/*
+ * Pick up some kernel type conventions:
+ */
+#define __user
+#define asmlinkage
+
+#ifdef __x86_64__
+#define __NR_perf_counter_open 298
+#define rmb()		asm volatile("lfence" ::: "memory")
+#define cpu_relax()	asm volatile("rep; nop" ::: "memory");
+#endif
+
+#ifdef __i386__
+#define __NR_perf_counter_open 336
+#define rmb()		asm volatile("lfence" ::: "memory")
+#define cpu_relax()	asm volatile("rep; nop" ::: "memory");
+#endif
+
+#ifdef __powerpc__
+#define __NR_perf_counter_open 319
+#define rmb()		asm volatile ("sync" ::: "memory")
+#define cpu_relax()	asm volatile ("" ::: "memory");
+#endif
+
+#define unlikely(x)	__builtin_expect(!!(x), 0)
+#define min(x, y) ({				\
+	typeof(x) _min1 = (x);			\
+	typeof(y) _min2 = (y);			\
+	(void) (&_min1 == &_min2);		\
+	_min1 < _min2 ? _min1 : _min2; })
+
+static inline int
+sys_perf_counter_open(struct perf_counter_hw_event *hw_event_uptr,
+		      pid_t pid, int cpu, int group_fd,
+		      unsigned long flags)
+{
+	return syscall(__NR_perf_counter_open, hw_event_uptr, pid, cpu,
+		       group_fd, flags);
+}
+
+#define MAX_COUNTERS			64
+#define MAX_NR_CPUS			256
+
+#define EID(type, id) (((__u64)(type) << PERF_COUNTER_TYPE_SHIFT) | (id))
+
+#endif