linux-kernel - [PATCH v11 8/8] x86/resctrl: Document the new "mba_MBps

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Message-ID: <20241206163148.83828-9-tony.luck@intel.com>
Date: Fri,  6 Dec 2024 08:31:48 -0800
From: Tony Luck <tony.luck@...el.com>
To: Fenghua Yu <fenghua.yu@...el.com>,
	Reinette Chatre <reinette.chatre@...el.com>,
	Peter Newman <peternewman@...gle.com>,
	Jonathan Corbet <corbet@....net>,
	x86@...nel.org
Cc: James Morse <james.morse@....com>,
	Jamie Iles <quic_jiles@...cinc.com>,
	Babu Moger <babu.moger@....com>,
	Randy Dunlap <rdunlap@...radead.org>,
	"Shaopeng Tan (Fujitsu)" <tan.shaopeng@...itsu.com>,
	linux-kernel@...r.kernel.org,
	linux-doc@...r.kernel.org,
	patches@...ts.linux.dev,
	Tony Luck <tony.luck@...el.com>
Subject: [PATCH v11 8/8] x86/resctrl: Document the new "mba_MBps_event" file

Add a section to document a new read/write file that shows/sets the memory
bandwidth event used to control bandwidth used by each CTRL_MON group.

Signed-off-by: Tony Luck <tony.luck@...el.com>
Reviewed-by: Reinette Chatre <reinette.chatre@...el.com>
---
 Documentation/arch/x86/resctrl.rst | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
index a824affd741d..6768fc1fad16 100644
--- a/Documentation/arch/x86/resctrl.rst
+++ b/Documentation/arch/x86/resctrl.rst
@@ -384,6 +384,16 @@ When monitoring is enabled all MON groups will also contain:
 	Available only with debug option. The identifier used by hardware
 	for the monitor group. On x86 this is the RMID.
 
+When the "mba_MBps" mount option is used all CTRL_MON groups will also contain:
+
+"mba_MBps_event":
+	Reading this file shows which memory bandwidth event is used
+	as input to the software feedback loop that keeps memory bandwidth
+	below the value specified in the schemata file. Writing the
+	name of one of the supported memory bandwidth events found in
+	/sys/fs/resctrl/info/L3_MON/mon_features changes the input
+	event.
+
 Resource allocation rules
 -------------------------
 
-- 
2.47.0