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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 Veillard      | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
daniel veillard com  | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library  http://libvirt.org/

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