From: Cody P Schafer <[email protected]>

Event parameters are a basic way for partial events to be specified in
sysfs with per-event names given to the fields that need to be filled in
when using a particular event.

It is intended for supporting cases where the single 'cpu' parameter is
insufficient. For example, POWER 8 has events for physical
sockets/cores/cpus that are accessible from with virtual machines. To
keep using the single 'cpu' parameter we'd need to perform a mapping
between Linux's cpus and the physical machine's cpus (in this case Linux
is running under a hypervisor). This isn't possible because bindings
between our cpus and physical cpus may not be fixed, and we probably
won't have a "cpu" on each physical cpu.

Signed-off-by: Cody P Schafer <[email protected]>
Signed-off-by: Sukadev Bhattiprolu <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Cc: Cody P Schafer <[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: Sukadev Bhattiprolu <[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 | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-events 
b/Documentation/ABI/testing/sysfs-bus-event_source-devices-events
index 20979f8b3edb..505f080d20a1 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-events
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-events
@@ -52,12 +52,18 @@ Description:        Per-pmu performance monitoring events 
specific to the running syste
                        event=0x2abc
                        event=0x423,inv,cmask=0x3
                        domain=0x1,offset=0x8,starting_index=0xffff
+                       domain=0x1,offset=0x8,core=?
 
                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.
 
+               In the case of the last example, a value replacing "?" would
+               need to be provided by the user selecting the particular event.
+               This is referred to as "event parameterization". Event
+               parameters have the format 'param=?'.
+
 What: /sys/bus/event_source/devices/<pmu>/events/<event>.unit
 Date: 2014/02/24
 Contact:       Linux kernel mailing list <[email protected]>
-- 
1.9.3

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