Re: [libvirt] [PATCH 1/3] nodeinfo: Add check and workaround to guarantee valid cpu topologies

Lately there were a few reports of the output of the virsh nodeinfo command being inaccurate. This patch ties to avoid that by checking if

the topology actualy makes sense. If it doesn't we then report a

synthetic topology that indicates to the user that the host capabilities should be checked for the actual topology. --- src/nodeinfo.c | 37 +++++++++++++++++++++++++++++++------ 1 file changed, 31 insertions(+), 6 deletions(-)

@@ -531,6 +539,23 @@ done: goto cleanup; } + /* Now check if the topology makes sense. There are machines that don't + * expose their real number of nodes or for example the AMD Bulldozer + * architecture that exposes their Clustered integer core modules as both + * threads and cores. This approach throws off our detection. Unfortunately + * the nodeinfo structure isn't designed to carry the full topology so + * we're going to lie about the detected topology to notify the user + * to check the host capabilities for the actual topology. */ + if ((nodeinfo->nodes * + nodeinfo->sockets * + nodeinfo->cores * + nodeinfo->threads) != (nodeinfo->cpus + offline)) { + nodeinfo->nodes = 1; + nodeinfo->sockets = nodeinfo->cpus; + nodeinfo->cores = 1;