arch/x86/topology.rst

1 .. SPDX-License-Identifier: GPL-2.0
11 The architecture-agnostic topology definitions are in
12 Documentation/admin-guide/cputopology.rst. This file holds x86-specific
17 Needless to say, code should use the generic functions - this file is *only*
35     - packages
36     - cores
37     - threads
48 Package-related topology information in the kernel:
50   - cpuinfo_x86.x86_max_cores:
54   - cpuinfo_x86.x86_max_dies:
58   - cpuinfo_x86.cpu_die_id:
62   - cpuinfo_x86.phys_proc_id:
70   - cpuinfo_x86.logical_proc_id:
77   - topology_max_packages():
82   - cpu_llc_id:
84     A per-CPU variable containing:
86       - On Intel, the first APIC ID of the list of CPUs sharing the Last Level
89       - On AMD, the Node ID or Core Complex ID containing the Last Level
95 A core consists of 1 or more threads. It does not matter whether the threads
96 are SMT- or CMT-type threads.
101 Core-related topology information in the kernel:
103   - smp_num_siblings:
114 CPU.
119 Thread-related topology information in the kernel:
121   - topology_core_cpumask():
128   - topology_sibling_cpumask():
133   - topology_logical_package_id():
137   - topology_physical_package_id():
141   - topology_core_id();
152   The alternative Linux CPU enumeration depends on how the BIOS enumerates the
153   threads. Many BIOSes enumerate all threads 0 first and then all threads 1.
154   That has the "advantage" that the logical Linux CPU numbers of threads 0 stay
158 1) Single Package, Single Core::
160    [package 0] -> [core 0] -> [thread 0] -> Linux CPU 0
166 	[package 0] -> [core 0] -> [thread 0] -> Linux CPU 0
167 		    -> [core 1] -> [thread 0] -> Linux CPU 1
171 	[package 0] -> [core 0] -> [thread 0] -> Linux CPU 0
172 				-> [thread 1] -> Linux CPU 1
173 		    -> [core 1] -> [thread 0] -> Linux CPU 2
174 				-> [thread 1] -> Linux CPU 3
178 	[package 0] -> [core 0] -> [thread 0] -> Linux CPU 0
179 				-> [thread 1] -> Linux CPU 2
180 		    -> [core 1] -> [thread 0] -> Linux CPU 1
181 				-> [thread 1] -> Linux CPU 3
185 	[node 0] -> [Compute Unit 0] -> [Compute Unit Core 0] -> Linux CPU 0
186 				     -> [Compute Unit Core 1] -> Linux CPU 1
187 		 -> [Compute Unit 1] -> [Compute Unit Core 0] -> Linux CPU 2
188 				     -> [Compute Unit Core 1] -> Linux CPU 3
194 	[package 0] -> [core 0] -> [thread 0] -> Linux CPU 0
195 		    -> [core 1] -> [thread 0] -> Linux CPU 1
197 	[package 1] -> [core 0] -> [thread 0] -> Linux CPU 2
198 		    -> [core 1] -> [thread 0] -> Linux CPU 3
202 	[package 0] -> [core 0] -> [thread 0] -> Linux CPU 0
203 				-> [thread 1] -> Linux CPU 1
204 		    -> [core 1] -> [thread 0] -> Linux CPU 2
205 				-> [thread 1] -> Linux CPU 3
207 	[package 1] -> [core 0] -> [thread 0] -> Linux CPU 4
208 				-> [thread 1] -> Linux CPU 5
209 		    -> [core 1] -> [thread 0] -> Linux CPU 6
210 				-> [thread 1] -> Linux CPU 7
214 	[package 0] -> [core 0] -> [thread 0] -> Linux CPU 0
215 				-> [thread 1] -> Linux CPU 4
216 		    -> [core 1] -> [thread 0] -> Linux CPU 1
217 				-> [thread 1] -> Linux CPU 5
219 	[package 1] -> [core 0] -> [thread 0] -> Linux CPU 2
220 				-> [thread 1] -> Linux CPU 6
221 		    -> [core 1] -> [thread 0] -> Linux CPU 3
222 				-> [thread 1] -> Linux CPU 7
226 	[node 0] -> [Compute Unit 0] -> [Compute Unit Core 0] -> Linux CPU 0
227 				     -> [Compute Unit Core 1] -> Linux CPU 1
228 		 -> [Compute Unit 1] -> [Compute Unit Core 0] -> Linux CPU 2
229 				     -> [Compute Unit Core 1] -> Linux CPU 3
231 	[node 1] -> [Compute Unit 0] -> [Compute Unit Core 0] -> Linux CPU 4
232 				     -> [Compute Unit Core 1] -> Linux CPU 5
233 		 -> [Compute Unit 1] -> [Compute Unit Core 0] -> Linux CPU 6
234 				     -> [Compute Unit Core 1] -> Linux CPU 7