[PATCH 02/15] perf Documentation: sysfs events/ interfaces

From: Arnaldo Carvalho de Melo
Date: Wed Oct 15 2014 - 16:53:17 EST


From: Cody P Schafer <dev@xxxxxxxxxx>

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 <dev@xxxxxxxxxx>
Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
Cc: Cody P Schafer <dev@xxxxxxxxxx>
Cc: Haren Myneni <hbabu@xxxxxxxxxx>
Cc: Haren Myneni <hbabu@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Michael Ellerman <michaele@xxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1412143402-26061-4-git-send-email-sukadev@xxxxxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
.../testing/sysfs-bus-event_source-devices-events | 60 ++++++++++++++++++++++
1 file changed, 60 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-events b/Documentation/ABI/testing/sysfs-bus-event_source-devices-events
index 7b40a3cbc26a..a5226f094159 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-events
+++ b/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 <linux-kernel@xxxxxxxxxxxxxxx>
+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 <linux-kernel@xxxxxxxxxxxxxxx>
+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 <linux-kernel@xxxxxxxxxxxxxxx>
+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.
--
1.9.3

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