x86/topology: Document cpu_llc_id

It means different things on Intel and AMD so write it down so that there's no confusion. Signed-off-by: Borislav Petkov <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Yazen Ghannam <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Thomas Gleixner <[email protected]> Signed-off-by: Ingo Molnar <[email protected]>
maraz · Dec 20, 2016 · a268b5f · a268b5f
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commit a268b5f
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diff --git a/Documentation/x86/topology.txt b/Documentation/x86/topology.txt
@@ -63,6 +63,15 @@ The topology of a system is described in the units of:
     The maximum possible number of packages in the system. Helpful for per
     package facilities to preallocate per package information.
 
+  - cpu_llc_id:
+
+    A per-CPU variable containing:
+    - On Intel, the first APIC ID of the list of CPUs sharing the Last Level
+    Cache
+
+    - On AMD, the Node ID or Core Complex ID containing the Last Level
+    Cache. In general, it is a number identifying an LLC uniquely on the
+    system.
 
 * Cores: