Hi Alexei and Daniel,

I got feedback from Fusion bios/chipset team. In short, the value
'possible' includes empty CPU socket. To verify, I tested on a
physical Xeon machine with 2 CPU sockets, one of them is empty. I got
'possible' = 0-239, the number of 'cpu*' =12. As a result, extra bytes
are copied from kernel to userspace.

As for Fusion, there is a configuration in *.vmx. If we disable cpu
hot plug by "vcpu.hotadd=FALSE", then 'possible' ==  the number of
'cpu*' dirs, which is the configuration in ESX. If "vcpu.hotadd=TURE",
then 'possible' is larger than 'cpu*' dirs, allowing users to add more
vcpus.

Regards,
William


On Fri, Aug 12, 2016 at 4:08 PM, Alexei Starovoitov
[off-list ref] wrote:

On Fri, Aug 12, 2016 at 09:58:51AM -0700, William Tu wrote:

quoted

Hi,

I've tested on ESXi version 5.5 and it seems OK.
- VM1: Ubuntu 14.04, kernel 3.19 ---> OK 3 cpu dirs, possible = 0-2
- VM2: Centos7, kernel 3.10 ---> OK 8 cpu dirs, possible = 0-7

I tried another MacBook with Fusion, same issue happens, the cpu[0-9]
dirs are not equal to /sys/devices/system/cpu/possible

great. thanks for testing. I think the issue is closed and
hopefully you can follow up with fusion guys ;)