1============================================================================== 2NUMA binding description. 3============================================================================== 4 5============================================================================== 61 - Introduction 7============================================================================== 8 9Systems employing a Non Uniform Memory Access (NUMA) architecture contain 10collections of hardware resources including processors, memory, and I/O buses, 11that comprise what is commonly known as a NUMA node. 12Processor accesses to memory within the local NUMA node is generally faster 13than processor accesses to memory outside of the local NUMA node. 14DT defines interfaces that allow the platform to convey NUMA node 15topology information to OS. 16 17============================================================================== 182 - numa-node-id 19============================================================================== 20 21For the purpose of identification, each NUMA node is associated with a unique 22token known as a node id. For the purpose of this binding 23a node id is a 32-bit integer. 24 25A device node is associated with a NUMA node by the presence of a 26numa-node-id property which contains the node id of the device. 27 28Example: 29 /* numa node 0 */ 30 numa-node-id = <0>; 31 32 /* numa node 1 */ 33 numa-node-id = <1>; 34 35============================================================================== 363 - distance-map 37============================================================================== 38 39The optional device tree node distance-map describes the relative 40distance (memory latency) between all numa nodes. 41 42- compatible : Should at least contain "numa-distance-map-v1". 43 44- distance-matrix 45 This property defines a matrix to describe the relative distances 46 between all numa nodes. 47 It is represented as a list of node pairs and their relative distance. 48 49 Note: 50 1. Each entry represents distance from first node to second node. 51 The distances are equal in either direction. 52 2. The distance from a node to self (local distance) is represented 53 with value 10 and all internode distance should be represented with 54 a value greater than 10. 55 3. distance-matrix should have entries in lexicographical ascending 56 order of nodes. 57 4. There must be only one device node distance-map which must 58 reside in the root node. 59 5. If the distance-map node is not present, a default 60 distance-matrix is used. 61 62Example: 63 4 nodes connected in mesh/ring topology as below, 64 65 0_______20______1 66 | | 67 | | 68 20 20 69 | | 70 | | 71 |_______________| 72 3 20 2 73 74 if relative distance for each hop is 20, 75 then internode distance would be, 76 0 -> 1 = 20 77 1 -> 2 = 20 78 2 -> 3 = 20 79 3 -> 0 = 20 80 0 -> 2 = 40 81 1 -> 3 = 40 82 83 and dt presentation for this distance matrix is, 84 85 distance-map { 86 compatible = "numa-distance-map-v1"; 87 distance-matrix = <0 0 10>, 88 <0 1 20>, 89 <0 2 40>, 90 <0 3 20>, 91 <1 0 20>, 92 <1 1 10>, 93 <1 2 20>, 94 <1 3 40>, 95 <2 0 40>, 96 <2 1 20>, 97 <2 2 10>, 98 <2 3 20>, 99 <3 0 20>, 100 <3 1 40>, 101 <3 2 20>, 102 <3 3 10>; 103 }; 104 105============================================================================== 1064 - Example dts 107============================================================================== 108 109Dual socket system consists of 2 boards connected through ccn bus and 110each board having one socket/soc of 8 cpus, memory and pci bus. 111 112 memory@c00000 { 113 device_type = "memory"; 114 reg = <0x0 0xc00000 0x0 0x80000000>; 115 /* node 0 */ 116 numa-node-id = <0>; 117 }; 118 119 memory@10000000000 { 120 device_type = "memory"; 121 reg = <0x100 0x0 0x0 0x80000000>; 122 /* node 1 */ 123 numa-node-id = <1>; 124 }; 125 126 cpus { 127 #address-cells = <2>; 128 #size-cells = <0>; 129 130 cpu@0 { 131 device_type = "cpu"; 132 compatible = "arm,armv8"; 133 reg = <0x0 0x0>; 134 enable-method = "psci"; 135 /* node 0 */ 136 numa-node-id = <0>; 137 }; 138 cpu@1 { 139 device_type = "cpu"; 140 compatible = "arm,armv8"; 141 reg = <0x0 0x1>; 142 enable-method = "psci"; 143 numa-node-id = <0>; 144 }; 145 cpu@2 { 146 device_type = "cpu"; 147 compatible = "arm,armv8"; 148 reg = <0x0 0x2>; 149 enable-method = "psci"; 150 numa-node-id = <0>; 151 }; 152 cpu@3 { 153 device_type = "cpu"; 154 compatible = "arm,armv8"; 155 reg = <0x0 0x3>; 156 enable-method = "psci"; 157 numa-node-id = <0>; 158 }; 159 cpu@4 { 160 device_type = "cpu"; 161 compatible = "arm,armv8"; 162 reg = <0x0 0x4>; 163 enable-method = "psci"; 164 numa-node-id = <0>; 165 }; 166 cpu@5 { 167 device_type = "cpu"; 168 compatible = "arm,armv8"; 169 reg = <0x0 0x5>; 170 enable-method = "psci"; 171 numa-node-id = <0>; 172 }; 173 cpu@6 { 174 device_type = "cpu"; 175 compatible = "arm,armv8"; 176 reg = <0x0 0x6>; 177 enable-method = "psci"; 178 numa-node-id = <0>; 179 }; 180 cpu@7 { 181 device_type = "cpu"; 182 compatible = "arm,armv8"; 183 reg = <0x0 0x7>; 184 enable-method = "psci"; 185 numa-node-id = <0>; 186 }; 187 cpu@8 { 188 device_type = "cpu"; 189 compatible = "arm,armv8"; 190 reg = <0x0 0x8>; 191 enable-method = "psci"; 192 /* node 1 */ 193 numa-node-id = <1>; 194 }; 195 cpu@9 { 196 device_type = "cpu"; 197 compatible = "arm,armv8"; 198 reg = <0x0 0x9>; 199 enable-method = "psci"; 200 numa-node-id = <1>; 201 }; 202 cpu@a { 203 device_type = "cpu"; 204 compatible = "arm,armv8"; 205 reg = <0x0 0xa>; 206 enable-method = "psci"; 207 numa-node-id = <1>; 208 }; 209 cpu@b { 210 device_type = "cpu"; 211 compatible = "arm,armv8"; 212 reg = <0x0 0xb>; 213 enable-method = "psci"; 214 numa-node-id = <1>; 215 }; 216 cpu@c { 217 device_type = "cpu"; 218 compatible = "arm,armv8"; 219 reg = <0x0 0xc>; 220 enable-method = "psci"; 221 numa-node-id = <1>; 222 }; 223 cpu@d { 224 device_type = "cpu"; 225 compatible = "arm,armv8"; 226 reg = <0x0 0xd>; 227 enable-method = "psci"; 228 numa-node-id = <1>; 229 }; 230 cpu@e { 231 device_type = "cpu"; 232 compatible = "arm,armv8"; 233 reg = <0x0 0xe>; 234 enable-method = "psci"; 235 numa-node-id = <1>; 236 }; 237 cpu@f { 238 device_type = "cpu"; 239 compatible = "arm,armv8"; 240 reg = <0x0 0xf>; 241 enable-method = "psci"; 242 numa-node-id = <1>; 243 }; 244 }; 245 246 pcie0: pcie0@848000000000 { 247 compatible = "arm,armv8"; 248 device_type = "pci"; 249 bus-range = <0 255>; 250 #size-cells = <2>; 251 #address-cells = <3>; 252 reg = <0x8480 0x00000000 0 0x10000000>; /* Configuration space */ 253 ranges = <0x03000000 0x8010 0x00000000 0x8010 0x00000000 0x70 0x00000000>; 254 /* node 0 */ 255 numa-node-id = <0>; 256 }; 257 258 pcie1: pcie1@948000000000 { 259 compatible = "arm,armv8"; 260 device_type = "pci"; 261 bus-range = <0 255>; 262 #size-cells = <2>; 263 #address-cells = <3>; 264 reg = <0x9480 0x00000000 0 0x10000000>; /* Configuration space */ 265 ranges = <0x03000000 0x9010 0x00000000 0x9010 0x00000000 0x70 0x00000000>; 266 /* node 1 */ 267 numa-node-id = <1>; 268 }; 269 270 distance-map { 271 compatible = "numa-distance-map-v1"; 272 distance-matrix = <0 0 10>, 273 <0 1 20>, 274 <1 1 10>; 275 }; 276