[PATCH v2 04/14] perf Documentation: add event parameters

From: Sukadev Bhattiprolu
Date: Fri Aug 15 2014 - 03:28:41 EST

From: Cody P Schafer <dev@xxxxxxxxxx>

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.

CC: Haren Myneni <hbabu@xxxxxxxxxx>
CC: Cody P Schafer <dev@xxxxxxxxxx>
Signed-off-by: Cody P Schafer <cody@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
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 20979f8..c1f9850 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
+ domain=0x1,offset=0x8,starting_index=phys_cpu

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 "phys_cpu"
+ would need to be provided by the user selecting the particular
+ event. This is refered to as "event parameterization". All
+ non-numerical values indicate an event parameter.
What: /sys/bus/event_source/devices/<pmu>/events/<event>.unit
Date: 2014/02/24
Contact: Linux kernel mailing list <linux-kernel@xxxxxxxxxxxxxxx>

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