| ============================================================================== |
| NUMA binding description. |
| ============================================================================== |
| |
| ============================================================================== |
| 1 - Introduction |
| ============================================================================== |
| |
| Systems employing a Non Uniform Memory Access (NUMA) architecture contain |
| collections of hardware resources including processors, memory, and I/O buses, |
| that comprise what is commonly known as a NUMA node. |
| Processor accesses to memory within the local NUMA node is generally faster |
| than processor accesses to memory outside of the local NUMA node. |
| DT defines interfaces that allow the platform to convey NUMA node |
| topology information to OS. |
| |
| ============================================================================== |
| 2 - numa-node-id |
| ============================================================================== |
| |
| For the purpose of identification, each NUMA node is associated with a unique |
| token known as a node id. For the purpose of this binding |
| a node id is a 32-bit integer. |
| |
| A device node is associated with a NUMA node by the presence of a |
| numa-node-id property which contains the node id of the device. |
| |
| Example: |
| /* numa node 0 */ |
| numa-node-id = <0>; |
| |
| /* numa node 1 */ |
| numa-node-id = <1>; |
| |
| ============================================================================== |
| 3 - distance-map |
| ============================================================================== |
| |
| The optional device tree node distance-map describes the relative |
| distance (memory latency) between all numa nodes. |
| |
| - compatible : Should at least contain "numa-distance-map-v1". |
| |
| - distance-matrix |
| This property defines a matrix to describe the relative distances |
| between all numa nodes. |
| It is represented as a list of node pairs and their relative distance. |
| |
| Note: |
| 1. Each entry represents distance from first node to second node. |
| The distances are equal in either direction. |
| 2. The distance from a node to self (local distance) is represented |
| with value 10 and all internode distance should be represented with |
| a value greater than 10. |
| 3. distance-matrix should have entries in lexicographical ascending |
| order of nodes. |
| 4. There must be only one device node distance-map which must |
| reside in the root node. |
| 5. If the distance-map node is not present, a default |
| distance-matrix is used. |
| |
| Example: |
| 4 nodes connected in mesh/ring topology as below, |
| |
| 0_______20______1 |
| | | |
| | | |
| 20 20 |
| | | |
| | | |
| |_______________| |
| 3 20 2 |
| |
| if relative distance for each hop is 20, |
| then internode distance would be, |
| 0 -> 1 = 20 |
| 1 -> 2 = 20 |
| 2 -> 3 = 20 |
| 3 -> 0 = 20 |
| 0 -> 2 = 40 |
| 1 -> 3 = 40 |
| |
| and dt presentation for this distance matrix is, |
| |
| distance-map { |
| compatible = "numa-distance-map-v1"; |
| distance-matrix = <0 0 10>, |
| <0 1 20>, |
| <0 2 40>, |
| <0 3 20>, |
| <1 0 20>, |
| <1 1 10>, |
| <1 2 20>, |
| <1 3 40>, |
| <2 0 40>, |
| <2 1 20>, |
| <2 2 10>, |
| <2 3 20>, |
| <3 0 20>, |
| <3 1 40>, |
| <3 2 20>, |
| <3 3 10>; |
| }; |
| |
| ============================================================================== |
| 4 - Example dts |
| ============================================================================== |
| |
| Dual socket system consists of 2 boards connected through ccn bus and |
| each board having one socket/soc of 8 cpus, memory and pci bus. |
| |
| memory@c00000 { |
| device_type = "memory"; |
| reg = <0x0 0xc00000 0x0 0x80000000>; |
| /* node 0 */ |
| numa-node-id = <0>; |
| }; |
| |
| memory@10000000000 { |
| device_type = "memory"; |
| reg = <0x100 0x0 0x0 0x80000000>; |
| /* node 1 */ |
| numa-node-id = <1>; |
| }; |
| |
| cpus { |
| #address-cells = <2>; |
| #size-cells = <0>; |
| |
| cpu@0 { |
| device_type = "cpu"; |
| compatible = "arm,armv8"; |
| reg = <0x0 0x0>; |
| enable-method = "psci"; |
| /* node 0 */ |
| numa-node-id = <0>; |
| }; |
| cpu@1 { |
| device_type = "cpu"; |
| compatible = "arm,armv8"; |
| reg = <0x0 0x1>; |
| enable-method = "psci"; |
| numa-node-id = <0>; |
| }; |
| cpu@2 { |
| device_type = "cpu"; |
| compatible = "arm,armv8"; |
| reg = <0x0 0x2>; |
| enable-method = "psci"; |
| numa-node-id = <0>; |
| }; |
| cpu@3 { |
| device_type = "cpu"; |
| compatible = "arm,armv8"; |
| reg = <0x0 0x3>; |
| enable-method = "psci"; |
| numa-node-id = <0>; |
| }; |
| cpu@4 { |
| device_type = "cpu"; |
| compatible = "arm,armv8"; |
| reg = <0x0 0x4>; |
| enable-method = "psci"; |
| numa-node-id = <0>; |
| }; |
| cpu@5 { |
| device_type = "cpu"; |
| compatible = "arm,armv8"; |
| reg = <0x0 0x5>; |
| enable-method = "psci"; |
| numa-node-id = <0>; |
| }; |
| cpu@6 { |
| device_type = "cpu"; |
| compatible = "arm,armv8"; |
| reg = <0x0 0x6>; |
| enable-method = "psci"; |
| numa-node-id = <0>; |
| }; |
| cpu@7 { |
| device_type = "cpu"; |
| compatible = "arm,armv8"; |
| reg = <0x0 0x7>; |
| enable-method = "psci"; |
| numa-node-id = <0>; |
| }; |
| cpu@8 { |
| device_type = "cpu"; |
| compatible = "arm,armv8"; |
| reg = <0x0 0x8>; |
| enable-method = "psci"; |
| /* node 1 */ |
| numa-node-id = <1>; |
| }; |
| cpu@9 { |
| device_type = "cpu"; |
| compatible = "arm,armv8"; |
| reg = <0x0 0x9>; |
| enable-method = "psci"; |
| numa-node-id = <1>; |
| }; |
| cpu@a { |
| device_type = "cpu"; |
| compatible = "arm,armv8"; |
| reg = <0x0 0xa>; |
| enable-method = "psci"; |
| numa-node-id = <1>; |
| }; |
| cpu@b { |
| device_type = "cpu"; |
| compatible = "arm,armv8"; |
| reg = <0x0 0xb>; |
| enable-method = "psci"; |
| numa-node-id = <1>; |
| }; |
| cpu@c { |
| device_type = "cpu"; |
| compatible = "arm,armv8"; |
| reg = <0x0 0xc>; |
| enable-method = "psci"; |
| numa-node-id = <1>; |
| }; |
| cpu@d { |
| device_type = "cpu"; |
| compatible = "arm,armv8"; |
| reg = <0x0 0xd>; |
| enable-method = "psci"; |
| numa-node-id = <1>; |
| }; |
| cpu@e { |
| device_type = "cpu"; |
| compatible = "arm,armv8"; |
| reg = <0x0 0xe>; |
| enable-method = "psci"; |
| numa-node-id = <1>; |
| }; |
| cpu@f { |
| device_type = "cpu"; |
| compatible = "arm,armv8"; |
| reg = <0x0 0xf>; |
| enable-method = "psci"; |
| numa-node-id = <1>; |
| }; |
| }; |
| |
| pcie0: pcie0@848000000000 { |
| compatible = "arm,armv8"; |
| device_type = "pci"; |
| bus-range = <0 255>; |
| #size-cells = <2>; |
| #address-cells = <3>; |
| reg = <0x8480 0x00000000 0 0x10000000>; /* Configuration space */ |
| ranges = <0x03000000 0x8010 0x00000000 0x8010 0x00000000 0x70 0x00000000>; |
| /* node 0 */ |
| numa-node-id = <0>; |
| }; |
| |
| pcie1: pcie1@948000000000 { |
| compatible = "arm,armv8"; |
| device_type = "pci"; |
| bus-range = <0 255>; |
| #size-cells = <2>; |
| #address-cells = <3>; |
| reg = <0x9480 0x00000000 0 0x10000000>; /* Configuration space */ |
| ranges = <0x03000000 0x9010 0x00000000 0x9010 0x00000000 0x70 0x00000000>; |
| /* node 1 */ |
| numa-node-id = <1>; |
| }; |
| |
| distance-map { |
| compatible = "numa-distance-map-v1"; |
| distance-matrix = <0 0 10>, |
| <0 1 20>, |
| <1 1 10>; |
| }; |
