cpupin in openstack memo
As we tested, when VCPU is less than CPU, if we bind vcpu to cpu， the perfromance of VM will be better. So we want to add this into Openstack as extended API.
The following memo is what in my mind now:
API :
1. Set instance vcpupin api：
PUT v2/{tenant_id}/vcpupin/{instance_id} Set instance vcpupin
Request parameters JSON:
{
"vcpupin" : [
{
vcpu : 0 # VCPU
cpulist : "1,2" # CPU List , This sample means VCPU0 can run in CPU1 and CPU2
},
{
vcpu : 1 # VCPU
cpulist : "3" # CPU List , This sample means VCPU1 can run in CPU3
}
]
}
2. Get instance vcpupin api：
GET v2/{tenant_id}/vcpupin/{instance_id} Get instance vcpupin status
Response parameters JSON:
{
"vcpupin" : [
{
vcpu : 0 # VCPU
currentcpu : 1 # VCPU is running on which CPU
state : "running" # State
cputime : "946.4" # cpu time, 946.4 means 946.4sec
cpulist : "1,2" # CPU List , This sample means VCPU0 can run in CPU1 and CPU2
},
{
vcpu : 1 # VCPU
currentcpu : 3 # VCPU is running on which CPU
state : "running" # State
cputime : "1001.2" # cpu time, 1001.2 means 1001.2sec
cpulist : "3" # CPU List , This sample means VCPU1 can run in CPU3
}
]
}
Function：
1. Basic call flow：
api/CLI client ----HTTP call---->
nova-api ----MQ:asyc call----> nova-compute
2. Set instance vcpupin ：
In nova-compute, call API/CLI do the thing like following:
Before cpupin:
[root@ci13sjcmp03 ~]# virsh vcpuinfo 1 <---1 is instance domain
VCPU: 0
CPU: 1
State: running
CPU time: 1.3s
CPU Affinity: yyyyyyyy <-- VCPU0 can run on CPU0-CPU8
Run cpupin:
[root@ci13sjcmp03 ~]# virsh vcpupin 1 0 1
After cpupin:
[root@ci13sjcmp03 ~]# virsh vcpuinfo 1
VCPU: 0
CPU: 1
State: running
CPU time: 1.3s
CPU Affinity: -y------ <-- VCPU0 can only run on CPU1
3. Get instance vcpupin ：
In nova-compute, call API/CLI do the thing like following:
[root@ci13sjcmp03 ~]# virsh vcpuinfo 1
VCPU: 0
CPU: 1
State: running
CPU time: 1.3s
CPU Affinity: -y------