Openstack中的虚拟机的cpu绑定

# vim /etc/nova/nova.conf

[DEFAULT]
vcpu_pin_set = 4-12,^8,15

重启nova服务，所有实例只能跑在CPUs 4,5,6,7,9,10,11,12,15上。

设置cpu绑定策略

flavor extra specs：

hw:cpu_policy=shared|dedicated

hw:cpu_threads_policy=avoid|separate|isolate|prefer

属性配置说明参见： http://specs.openstack.org/openstack/nova-specs/specs/kilo/implemented/virt-driver-cpu-pinning.html

也就是说这个所谓的绑定，并不是让用户显式的将一个vcpu绑定到某一物理cpu上，openstack不会暴露给用户物理cpu的layout信息；它的使用只是由用户指定绑定选项dedicated，并制定绑定策略，由nova来通过一系列调度具体选择绑定某个vcpu到某一pcpu上。使用方法一般是建两个host-aggregate，一个叫cpu_pinning，一个叫normal，两个aggregate加入不同物理机，有绑定需求的虚机使用cpu_pinning这个aggregate中的物理机建虚机。不会将有绑定需求和没有绑定需求的cpu放在同一个物理机上

也可以通过修改虚拟机XML配置文件制定vcpu绑定到某一个具体的pcpu

手动修改cpu绑定

修改虚拟机XML配置文件：

<vcpu placement='static' cpuset='0'>1</vcpu>
...
    <topology sockets='1' cores='1' threads='1'/>

# virsh vcpupin instance-00008205
VCPU: CPU Affinity
----------------------------------
   0: 0

# virsh vcpuinfo instance-00008205
VCPU:           0
CPU:            0
State:          running
CPU time:       7.7s
CPU Affinity:   y---------------

  <vcpu placement='static' cpuset='0,2,4,10,12'>5</vcpu>
  <cputune>
    <vcpupin vcpu='0' cpuset='0'/>
    <vcpupin vcpu='1' cpuset='2'/>
    <vcpupin vcpu='2' cpuset='12'/>
    <vcpupin vcpu='3' cpuset='10'/>
    <vcpupin vcpu='4' cpuset='4'/>
  </cputune>

    <topology sockets='1' cores='5' threads='1'/>

# virsh vcpupin instance-00008205
VCPU: CPU Affinity
----------------------------------
   0: 0
   1: 2
   2: 12
   3: 10
   4: 4

# virsh vcpuinfo instance-00008205
VCPU:           0
CPU:            0
State:          running
CPU time:       35.4s
CPU Affinity:   y---------------

VCPU:           1
CPU:            2
State:          running
CPU Affinity:   --y-------------

VCPU:           2
CPU:            12
State:          running
CPU Affinity:   ------------y---

VCPU:           3
CPU:            10
State:          running
CPU Affinity:   ----------y-----

VCPU:           4
CPU:            4
State:          running
CPU Affinity:   ----y-----------

自动修改cpu绑定

# 通过修改虚拟机xml配置文件，制定vcpu和pcpu的绑定关系
ssh_client = SSHClient(ip, user, password)
cputune_subxml = ""
cpuset = []
for cpu_pin in cpu_pin_info:
    cpu_pin_xml = ("<vcpupin vcpu='%s' cpuset='%s'/>"
                   % (cpu_pin[0], cpu_pin[1]))
    cputune_subxml += cpu_pin_xml
    cpuset.append(str(cpu_pin[1]))
sed_command = ("s|<vcpu placement=.*$|"
               "<vcpu placement='static' cpuset='%s'>%s</vcpu>|g;"
               "s|<topology sockets=.*$|"
               "<topology sockets='1' cores='%s' threads='1'/>|g;"
               % (",".join(cpuset), len(cpu_pin_info),
                  len(cpu_pin_info)))
if cputune_subxml:
    sed_command += ("/<cputune>/,/<\\/cputune>/d;")
    sed_command += ("/<vcpu placement/a\\<cputune>%s<\\/cputune>"
                    % cputune_subxml)
command = ("EDITOR=\"sed -i \\\"%s\\\"\" virsh edit %s"
           % (sed_command, instance_name))
LOG.debug("Set cpu pinnig. command=%s" % command)
ssh_client.exec_command(command)