perf Documentation: sysfs events/ interfaces

Add documentation for the <event>, <event>.scale, and <event>.unit
files in sysfs.

	<event>.scale and <event>.unit were undocumented.
	<event> was previously documented only for specific powerpc pmu events.

Signed-off-by: Cody P Schafer <[email protected]>
Signed-off-by: Sukadev Bhattiprolu <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Cody P Schafer <[email protected]>
Cc: Haren Myneni <[email protected]>
Cc: Haren Myneni <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Documentation/ABI/testing/sysfs-bus-event_source-devices-events

@@ -599,3 +599,63 @@ Description:	POWER-systems specific performance monitoring events
 		Further, multiple terms like 'event=0xNNNN' can be specified
 		and separated with comma. All available terms are defined in
 		the /sys/bus/event_source/devices/<dev>/format file.
+
+What: /sys/bus/event_source/devices/<pmu>/events/<event>
+Date: 2014/02/24
+Contact:	Linux kernel mailing list <[email protected]>
+Description:	Per-pmu performance monitoring events specific to the running system
+
+		Each file (except for some of those with a '.' in them, '.unit'
+		and '.scale') in the 'events' directory describes a single
+		performance monitoring event supported by the <pmu>. The name
+		of the file is the name of the event.
+
+		File contents:
+
+			<term>[=<value>][,<term>[=<value>]]...
+
+		Where <term> is one of the terms listed under
+		/sys/bus/event_source/devices/<pmu>/format/ and <value> is
+		a number is base-16 format with a '0x' prefix (lowercase only).
+		If a <term> is specified alone (without an assigned value), it
+		is implied that 0x1 is assigned to that <term>.
+
+		Examples (each of these lines would be in a seperate file):
+
+			event=0x2abc
+			event=0x423,inv,cmask=0x3
+			domain=0x1,offset=0x8,starting_index=0xffff
+
+		Each of the assignments indicates a value to be assigned to a
+		particular set of bits (as defined by the format file
+		corresponding to the <term>) in the perf_event structure passed
+		to the perf_open syscall.
+
+What: /sys/bus/event_source/devices/<pmu>/events/<event>.unit
+Date: 2014/02/24
+Contact:	Linux kernel mailing list <[email protected]>
+Description:	Perf event units
+
+		A string specifying the English plural numerical unit that <event>
+		(once multiplied by <event>.scale) represents.
+
+		Example:
+
+			Joules
+
+What: /sys/bus/event_source/devices/<pmu>/events/<event>.scale
+Date: 2014/02/24
+Contact:	Linux kernel mailing list <[email protected]>
+Description:	Perf event scaling factors
+
+		A string representing a floating point value expressed in
+		scientific notation to be multiplied by the event count
+		recieved from the kernel to match the unit specified in the
+		<event>.unit file.
+
+		Example:
+
+			2.3283064365386962890625e-10
+
+		This is provided to avoid performing floating point arithmetic
+		in the kernel.