1 ==============================================
2 NUMA binding description.
3 ==============================================
4
5 ==============================================
6 1 - Introduction
7 ==============================================
8
9 Systems employing a Non Uniform Memory Access
10 collections of hardware resources including pr
11 that comprise what is commonly known as a NUMA
12 Processor accesses to memory within the local
13 than processor accesses to memory outside of t
14 DT defines interfaces that allow the platform
15 topology information to OS.
16
17 ==============================================
18 2 - numa-node-id
19 ==============================================
20
21 For the purpose of identification, each NUMA n
22 token known as a node id. For the purpose of t
23 a node id is a 32-bit integer.
24
25 A device node is associated with a NUMA node b
26 numa-node-id property which contains the node
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 des
40 distance (memory latency) between all numa nod
41
42 - compatible : Should at least contain "numa-d
43
44 - distance-matrix
45 This property defines a matrix to describe t
46 between all numa nodes.
47 It is represented as a list of node pairs an
48
49 Note:
50 1. Each entry represents distance from
51 The distances are equal in either dire
52 2. The distance from a node to self (l
53 with value 10 and all internode distan
54 a value greater than 10.
55 3. distance-matrix should have entries
56 order of nodes.
57 4. There must be only one device node
58 reside in the root node.
59 5. If the distance-map node is not pre
60 distance-matrix is used.
61
62 Example:
63 4 nodes connected in mesh/ring topolog
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 2
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 mat
84
85 distance-map {
86 compatible = "numa-di
87 distance-matrix = <0
88 <0
89 <0
90 <0
91 <1
92 <1
93 <1
94 <1
95 <2
96 <2
97 <2
98 <2
99 <3
100 <3
101 <3
102 <3
103 };
104
105 ==============================================
106 4 - Empty memory nodes
107 ==============================================
108
109 Empty memory nodes, which no memory resides in
110 device nodes for these empty memory nodes. How
111 distance maps are still valid and memory may b
112 hotplug afterwards.
113
114 Example:
115
116 memory@0 {
117 device_type = "memory";
118 reg = <0x0 0x0 0x0 0x80000000>
119 numa-node-id = <0>;
120 };
121
122 memory@80000000 {
123 device_type = "memory";
124 reg = <0x0 0x80000000 0x0 0x80
125 numa-node-id = <1>;
126 };
127
128 /* Empty memory node 2 and 3 */
129 distance-map {
130 compatible = "numa-distance-ma
131 distance-matrix = <0 0 10>,
132 <0 1 20>,
133 <0 2 40>,
134 <0 3 20>,
135 <1 0 20>,
136 <1 1 10>,
137 <1 2 20>,
138 <1 3 40>,
139 <2 0 40>,
140 <2 1 20>,
141 <2 2 10>,
142 <2 3 20>,
143 <3 0 20>,
144 <3 1 40>,
145 <3 2 20>,
146 <3 3 10>;
147 };
148
149 ==============================================
150 5 - Example dts
151 ==============================================
152
153 Dual socket system consists of 2 boards connec
154 each board having one socket/soc of 8 cpus, me
155
156 memory@c00000 {
157 device_type = "memory";
158 reg = <0x0 0xc00000 0x0 0x8000
159 /* node 0 */
160 numa-node-id = <0>;
161 };
162
163 memory@10000000000 {
164 device_type = "memory";
165 reg = <0x100 0x0 0x0 0x8000000
166 /* node 1 */
167 numa-node-id = <1>;
168 };
169
170 cpus {
171 #address-cells = <2>;
172 #size-cells = <0>;
173
174 cpu@0 {
175 device_type = "cpu";
176 compatible = "arm,arm
177 reg = <0x0 0x0>;
178 enable-method = "psci"
179 /* node 0 */
180 numa-node-id = <0>;
181 };
182 cpu@1 {
183 device_type = "cpu";
184 compatible = "arm,arm
185 reg = <0x0 0x1>;
186 enable-method = "psci"
187 numa-node-id = <0>;
188 };
189 cpu@2 {
190 device_type = "cpu";
191 compatible = "arm,arm
192 reg = <0x0 0x2>;
193 enable-method = "psci"
194 numa-node-id = <0>;
195 };
196 cpu@3 {
197 device_type = "cpu";
198 compatible = "arm,arm
199 reg = <0x0 0x3>;
200 enable-method = "psci"
201 numa-node-id = <0>;
202 };
203 cpu@4 {
204 device_type = "cpu";
205 compatible = "arm,arm
206 reg = <0x0 0x4>;
207 enable-method = "psci"
208 numa-node-id = <0>;
209 };
210 cpu@5 {
211 device_type = "cpu";
212 compatible = "arm,arm
213 reg = <0x0 0x5>;
214 enable-method = "psci"
215 numa-node-id = <0>;
216 };
217 cpu@6 {
218 device_type = "cpu";
219 compatible = "arm,arm
220 reg = <0x0 0x6>;
221 enable-method = "psci"
222 numa-node-id = <0>;
223 };
224 cpu@7 {
225 device_type = "cpu";
226 compatible = "arm,arm
227 reg = <0x0 0x7>;
228 enable-method = "psci"
229 numa-node-id = <0>;
230 };
231 cpu@8 {
232 device_type = "cpu";
233 compatible = "arm,arm
234 reg = <0x0 0x8>;
235 enable-method = "psci"
236 /* node 1 */
237 numa-node-id = <1>;
238 };
239 cpu@9 {
240 device_type = "cpu";
241 compatible = "arm,arm
242 reg = <0x0 0x9>;
243 enable-method = "psci"
244 numa-node-id = <1>;
245 };
246 cpu@a {
247 device_type = "cpu";
248 compatible = "arm,arm
249 reg = <0x0 0xa>;
250 enable-method = "psci"
251 numa-node-id = <1>;
252 };
253 cpu@b {
254 device_type = "cpu";
255 compatible = "arm,arm
256 reg = <0x0 0xb>;
257 enable-method = "psci"
258 numa-node-id = <1>;
259 };
260 cpu@c {
261 device_type = "cpu";
262 compatible = "arm,arm
263 reg = <0x0 0xc>;
264 enable-method = "psci"
265 numa-node-id = <1>;
266 };
267 cpu@d {
268 device_type = "cpu";
269 compatible = "arm,arm
270 reg = <0x0 0xd>;
271 enable-method = "psci"
272 numa-node-id = <1>;
273 };
274 cpu@e {
275 device_type = "cpu";
276 compatible = "arm,arm
277 reg = <0x0 0xe>;
278 enable-method = "psci"
279 numa-node-id = <1>;
280 };
281 cpu@f {
282 device_type = "cpu";
283 compatible = "arm,arm
284 reg = <0x0 0xf>;
285 enable-method = "psci"
286 numa-node-id = <1>;
287 };
288 };
289
290 pcie0: pcie0@848000000000 {
291 compatible = "arm,armv8";
292 device_type = "pci";
293 bus-range = <0 255>;
294 #size-cells = <2>;
295 #address-cells = <3>;
296 reg = <0x8480 0x00000000 0 0x1
297 ranges = <0x03000000 0x8010 0x
298 /* node 0 */
299 numa-node-id = <0>;
300 };
301
302 pcie1: pcie1@948000000000 {
303 compatible = "arm,armv8";
304 device_type = "pci";
305 bus-range = <0 255>;
306 #size-cells = <2>;
307 #address-cells = <3>;
308 reg = <0x9480 0x00000000 0 0x1
309 ranges = <0x03000000 0x9010 0x
310 /* node 1 */
311 numa-node-id = <1>;
312 };
313
314 distance-map {
315 compatible = "numa-distance-ma
316 distance-matrix = <0 0 10>,
317 <0 1 20>,
318 <1 1 10>;
319 };
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