[PATCH 8/8] topology: Update CPU topology documentation

[Andreas Herrmann]

Mention new attributes introduced for multi-node processor support.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@xxxxxxx>
---
 Documentation/cputopology.txt |   35 +++++++++++++++++++++++++++++------
 1 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt
index b41f3e5..48914b1 100644
--- a/Documentation/cputopology.txt
+++ b/Documentation/cputopology.txt
@@ -3,13 +3,32 @@ Export cpu topology info via sysfs. Items (attributes) are similar
 to /proc/cpuinfo.
 
 1) /sys/devices/system/cpu/cpuX/topology/physical_package_id:
-represent the physical package id of  cpu X;
+   represents the physical package id of cpu X;
 2) /sys/devices/system/cpu/cpuX/topology/core_id:
-represent the cpu core id to cpu X;
-3) /sys/devices/system/cpu/cpuX/topology/thread_siblings:
-represent the thread siblings to cpu X in the same core;
-4) /sys/devices/system/cpu/cpuX/topology/core_siblings:
-represent the thread siblings to cpu X in the same physical package;
+   represents the cpu core id of cpu X;
+3) /sys/devices/system/cpu/cpuX/topology/cpu_node_id:
+   represents the processor internal node_id of cpu X;
+4) /sys/devices/system/cpu/cpuX/topology/thread_siblings:
+   represents the thread siblings of cpu X in the same core;
+5) /sys/devices/system/cpu/cpuX/topology/core_siblings:
+   represents the thread siblings of cpu X in the same processor
+   internal node;
+6) /sys/devices/system/cpu/cpuX/topology/cpu_node_siblings:
+   represents the thread siblings of cpu X in the same physical
+   package;
+
+Note: cpu_node_siblings and core_siblings differ only on
+      multi-node processors. On all other processors they are
+      identical and then cpu_node_id is always 0.
+
+With that CPU topology is mapped into following hierarchy:
+
+  Level        | Set of CPUs
+ --------------|---------------
+  phys_package | cpu_node_siblings
+  cpu_node     | core_siblings
+  core         | thread_siblings
+  thread       | one CPU
 
 To implement it in an architecture-neutral way, a new source file,
 drivers/base/topology.c, is to export the 4 attributes.
@@ -20,6 +39,8 @@ these macros in include/asm-XXX/topology.h:
 #define topology_core_id(cpu)
 #define topology_thread_cpumask(cpu)
 #define topology_core_cpumask(cpu)
+#define topology_cpu_node_id(cpu)
+#define topology_cpu_node_siblings(cpu)
 
 The type of **_id is int.
 The type of siblings is (const) struct cpumask *.
@@ -31,6 +52,8 @@ not defined by include/asm-XXX/topology.h:
 2) core_id: 0
 3) thread_siblings: just the given CPU
 4) core_siblings: just the given CPU
+5) cpu_node_id: 0
+6) cpu_node_siblings: identical to core_siblings
 
 Additionally, cpu topology information is provided under
 /sys/devices/system/cpu and includes these files.  The internal
-- 
1.6.3.3



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