projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 2bc4da1d GK |
1 | ============================================================================== |
| 2 | NUMA binding description. | |
| 3 | ============================================================================== | |
| 4 | ||
| 5 | ============================================================================== | |
| 6 | 1 - Introduction | |
| 7 | ============================================================================== | |
| 8 | ||
| 9 | Systems employing a Non Uniform Memory Access (NUMA) architecture contain | |
| 10 | collections of hardware resources including processors, memory, and I/O buses, | |
| 11 | that comprise what is commonly known as a NUMA node. | |
| 12 | Processor accesses to memory within the local NUMA node is generally faster | |
| 13 | than processor accesses to memory outside of the local NUMA node. | |
| 14 | DT defines interfaces that allow the platform to convey NUMA node | |
| 15 | topology information to OS. | |
| 16 | ||
| 17 | ============================================================================== | |
| 18 | 2 - numa-node-id | |
| 19 | ============================================================================== | |
| 20 | ||
| 21 | For the purpose of identification, each NUMA node is associated with a unique | |
| 22 | token known as a node id. For the purpose of this binding | |
| 23 | a node id is a 32-bit integer. | |
| 24 | ||
| 25 | A device node is associated with a NUMA node by the presence of a | |
| 26 | numa-node-id property which contains the node id of the device. | |
| 27 | ||
| 28 | Example: | |
| 29 | /* numa node 0 */ | |
| 30 | numa-node-id = <0>; | |
| 31 | ||
| 32 | /* numa node 1 */ | |
| 33 | numa-node-id = <1>; | |
| 34 | ||
| 35 | ============================================================================== | |
| 36 | 3 - distance-map | |
| 37 | ============================================================================== | |
| 38 | ||
| 39 | The optional device tree node distance-map describes the relative | |
| 40 | distance (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 | ||
| 62 | Example: | |
| 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 | ============================================================================== | |
| 106 | 4 - Example dts | |
| 107 | ============================================================================== | |
| 108 | ||
| 109 | Dual socket system consists of 2 boards connected through ccn bus and | |
| 110 | each 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 | }; |