Subject: Re: [PATCH v6 3/4] perf Documentation: add event parameters

From: Sukadev Bhattiprolu <[email-masked]>
Date: Tue, 23 Dec 2014 11:59:34 -0800

>>From bfc20fd2161060cc51f3f24aa91663da39e97750 Mon Sep 17 00:00:00 2001
From: Cody P Schafer <[email-masked]>
Date: Wed, 24 Sep 2014 12:27:22 -0700
Subject: [PATCH 3/4] perf Documentation: add event parameters

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.

Changelog[v6]
	Update event description to explain how required parameters
	are displayed.

CC: Sukadev Bhattiprolu <[email-masked]>
CC: Haren Myneni <[email-masked]>
CC: Cody P Schafer <[email-masked]>
Signed-off-by: Cody P Schafer <[email-masked]>
---
 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..505f080 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-masked]>
-- 
1.8.3.1