Re: [libvirt] [PATCH v3] qemu: Support numad

On Thu, Mar 08, 2012 at 09:36:26PM +0800, Osier Yang wrote: > 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. > > v2 - v3: > * XML schema is changed to<vcpu placement="static|auto">4</vcpu> > * Affected tests are updated > * LXC driver's support is dropped, let's see what's the real > performance on qemu driver first. > > v1 - v2: > * Since Bill Gray says it doesn't matter to use the number of > vcpus and current memory amount as numad cmd line argument, > though from sementics point of view, what numad expects are > physical CPU numbers, let's go this way. > v2 dropped XML<cpu required_cpu='4' required_memory='512000'/>, > and just a new boolean XML element<autonuma>. Codes are refactored > accordingly. > > * v1 overrides the cpuset specified by<vcpu cpuset='1-10,^7'>2</vcpu>, > v2 doesn't do that, but just silently ignored. > > * xml2xml test is added A relatively long patch, but I went through it and it looks okay, ACK from me but I would appreciate someone else to have a quick look :-) Daniel