In the 'topology' element it is mentioned, regarding the sockets value, "They refer to the total number of CPU sockets". This is not accurate. What we're doing is calculating the number of sockets per NUMA node, which can be checked in the current implementation of virHostCPUGetInfoPopulateLinux(). Calculating the total number of sockets would break the topology sanity check nodes*sockets*cores*threads=online_cpus. This documentation fix is important to avoid user confusion when seeing the output of 'virsh capabilities' and expecting it to be equal to the output of 'lscpu'. E.g in a Power 9 host this 'lscpu' output: Architecture: ppc64le Byte Order: Little Endian CPU(s): 160 On-line CPU(s) list: 0-159 Thread(s) per core: 4 Core(s) per socket: 20 Socket(s): 2 NUMA node(s): 2 Model: 2.2 (pvr 004e 1202) Model name: POWER9, altivec supported And this XML output from virsh capabilities: <cpu> <arch>ppc64le</arch> <model>POWER9</model> <vendor>IBM</vendor> <topology sockets='1' dies='1' cores='20' threads='4'/> (...) </cpu> Both are correct, as long as we mention in the Libvirt documentation that 'sockets' in the topology element represents the number of sockets per NUMA node. Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> --- docs/formatdomain.html.in | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index aaeb05961f..7940d6ace5 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -1675,9 +1675,9 @@ <dd>The <code>topology</code> element specifies requested topology of virtual CPU provided to the guest. Four attributes, <code>sockets</code>, <code>dies</code>, <code>cores</code>, and <code>threads</code>, - accept non-zero positive integer values. They refer to the total number - of CPU sockets, number of dies per socket, number of cores per die, and - number of threads per core, respectively. The <code>dies</code> + accept non-zero positive integer values. They refer to the number of + CPU sockets per NUMA node, number of dies per socket, number of cores + per die, and number of threads per core, respectively. The <code>dies</code> attribute is optional and will default to 1 if omitted, while the other attributes are all mandatory. Hypervisors may require that the maximum number of vCPUs specified by the <code>cpus</code> element equals to -- 2.25.1