[Xen-devel] strange phenomenon on CPU affinity

[周理科 <likechou@xxxxxxxxx>]

Hello,

     My testing machine has 2 quad-core CPU (It supports hyperthreading, but i disable it in BIOS). I uses Xen 4.0.1 as the hypervisor. When I use 8 VMs to conduct a test, CPU affinity of the VMs is very strange. Like this:

vm_name  vcpu_num  cpu_affinity

Domain-0    8      any

VM1            4      1,3,5,7

VM2            4      1,3,5,7

VM3            4      1,3,5,7

VM4            4      1,3,5,7

VM5            4      1,3,5,7

VM6            4      0,2,4,6

VM7            4      0,2,4,6

VM8            4      0,2,4,6

I do not set the CPU affinity in the configuration file, and I cannot find when the hypervisor set the CPU affinity in the source code. In this situation, 4 VCPUs of each VM are binding to 4 PCPUs permanently, and 5 VMs run on a set of PCPUs, and others run on the other set of PCPUs. It is unfair to these VMs. 

--
Like Zhou

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