Re: [libvirt] [PATCH v2 2/2] virCaps: Expose distance between host NUMA nodes

If user or management application wants to create a guest, it may be useful to know the cost of internode latencies before the guest resources are pinned. For example: <capabilities> <host> ... <topology> <cells num='2'> <cell id='0'> <memory unit='KiB'>4004132</memory> <distances> <sibling id='0' value='10'/> <sibling id='1' value='20'/> </distances> <cpus num='2'> <cpu id='0' socket_id='0' core_id='0' siblings='0'/> <cpu id='2' socket_id='0' core_id='2' siblings='2'/> </cpus> </cell> <cell id='1'> <memory unit='KiB'>4030064</memory> <distances> <sibling id='0' value='20'/> <sibling id='1' value='10'/> </distances> <cpus num='2'> <cpu id='1' socket_id='0' core_id='0' siblings='1'/> <cpu id='3' socket_id='0' core_id='2' siblings='3'/> </cpus> </cell> </cells> </topology> ... </host> ... </capabilities> we can see the distance from node1 to node0 is 20 and within nodes 10. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- docs/schemas/capability.rng | 15 +++++++++++ src/conf/capabilities.c | 19 +++++++++++++- src/conf/capabilities.h | 13 +++++++++- src/libxl/libxl_conf.c | 4 +-- src/nodeinfo.c | 61 ++++++++++++++++++++++++++++++++++++++++++--- src/test/test_driver.c | 2 +- src/xen/xend_internal.c | 3 ++- tests/vircapstest.c | 4 +-- 8 files changed, 110 insertions(+), 11 deletions(-)

@@ -766,6 +771,18 @@ virCapabilitiesFormatNUMATopology(virBufferPtr buf, virBufferAsprintf(buf, "<memory unit='KiB'>%llu</memory>\n", cells[i]->mem); + if (cells[i]->nsiblings) { + virBufferAddLit(buf, "<distances>\n"); + virBufferAdjustIndent(buf, 2); + for (j = 0; j < cells[i]->nsiblings; j++) { + virBufferAsprintf(buf, "<sibling id='%d' value='%d'/>\n", + cells[i]->siblings[j].node, + cells[i]->siblings[j].distance); + } + virBufferAdjustIndent(buf, -2); + virBufferAddLit(buf, "</distances>\n"); + }

@@ -194,8 +203,10 @@ extern int virCapabilitiesAddHostNUMACell(virCapsPtr caps, int num, int ncpus, + int nsiblings,

unsigned long long mem, - virCapsHostNUMACellCPUPtr cpus); + virCapsHostNUMACellCPUPtr cpus, + virCapsHostNUMACellSiblingInfoPtr siblings); extern int