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authorFenghua Yu <fenghua.yu@intel.com>2017-07-25 15:39:04 -0700
committerThomas Gleixner <tglx@linutronix.de>2017-08-01 22:41:30 +0200
commit0dd2d7494cd818d06a2ae1cd840cd62124a2d25e (patch)
tree9021ddec571d72febd154583ad8dee5d3f9adc6f /Documentation/x86
parente33026831bdb5f051499fec6a606f79fe1f94cc8 (diff)
x86/intel_rdt: Show bitmask of shareable resource with other executing units
CPUID.(EAX=0x10, ECX=res#):EBX[31:0] reports a bit mask for a resource. Each set bit within the length of the CBM indicates the corresponding unit of the resource allocation may be used by other entities in the platform (e.g. an integrated graphics engine or hardware units outside the processor core and have direct access to the resource). Each cleared bit within the length of the CBM indicates the corresponding allocation unit can be configured to implement a priority-based allocation scheme without interference with other hardware agents in the system. Bits outside the length of the CBM are reserved. More details on the bit mask are described in x86 Software Developer's Manual. The bitmask is shown in "info" directory for each resource. It's up to user to decide how to use the bitmask within a CBM in a partition to share or isolate a resource with other executing units. Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: ravi.v.shankar@intel.com Cc: peterz@infradead.org Cc: eranian@google.com Cc: ak@linux.intel.com Cc: davidcc@google.com Cc: vikas.shivappa@linux.intel.com Link: http://lkml.kernel.org/r/20170725223904.12996-1-tony.luck@intel.com
Diffstat (limited to 'Documentation/x86')
-rw-r--r--Documentation/x86/intel_rdt_ui.txt7
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/x86/intel_rdt_ui.txt b/Documentation/x86/intel_rdt_ui.txt
index 76f21e2ac176..4d8848e4e224 100644
--- a/Documentation/x86/intel_rdt_ui.txt
+++ b/Documentation/x86/intel_rdt_ui.txt
@@ -48,6 +48,13 @@ related to allocation:
"min_cbm_bits": The minimum number of consecutive bits which
must be set when writing a mask.
+"shareable_bits": Bitmask of shareable resource with other executing
+ entities (e.g. I/O). User can use this when
+ setting up exclusive cache partitions. Note that
+ some platforms support devices that have their
+ own settings for cache use which can over-ride
+ these bits.
+
Memory bandwitdh(MB) subdirectory contains the following files
with respect to allocation: