numad is an user-level daemon that monitors NUMA topology and
processes resource consumption to facilitate good NUMA resource
alignment of applications/virtual machines to improve performance
and minimize cost of remote memory latencies. It provides a
pre-placement advisory interface, so significant processes can
be pre-bound to nodes with sufficient available resources.
More details: http://fedoraproject.org/wiki/Features/numad
"numad -w ncpus:memory_amount" is the advisory interface numad
provides currently.
This patch add the support by introducing a new XML attribute
for <vcpu>. e.g.
<vcpu placement="auto">4</vcpu>
<vcpu placement="static" cpuset="1-10^6">4</vcpu>
The returned advisory nodeset from numad will be printed
in domain's dumped XML. e.g.
<vcpu placement="auto" cpuset="1-10^6">4</vcpu>
If placement is "auto", the number of vcpus and the current
memory amount specified in domain XML will be used for numad
command line (numad uses MB for memory amount):
numad -w $num_of_vcpus:$current_memory_amount / 1024
The advisory nodeset returned from numad will be used to set
domain process CPU affinity then. (e.g. qemuProcessInitCpuAffinity).
If the user specifies both CPU affinity policy (e.g.
(<vcpu cpuset="1-10,^7,^8">4</vcpu>) and placement == "auto"
the specified CPU affinity will be overridden.
Only QEMU/KVM drivers support it now.
See docs update in patch for more details.
0f8e7ae33a
