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Subject[PATCH v5 3/4] perf Documentation: add event parameters
Date
From: Cody P Schafer <cody@linux.vnet.ibm.com>

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: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
CC: Haren Myneni <hbabu@us.ibm.com>
CC: Cody P Schafer <dev@codyps.com>
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
---
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..f584b16 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,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 referred 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@vger.kernel.org>
--
1.8.3.1


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