best choice among combos of physical CPUs x cores/CPU

[charlin]

hi,

What is the best combination of sockets (physical CPUs) x cores/socket that would best utilize SMP function of the Guest OS (Linux)?

For example, if an ESXi 5.0 host has 4 physical CPUs, each CPU has 10 cores, total of 40 vCPU are available to VMs.

If I want to build a virtual machine that needs 8 vCPU, what is best combo to get 8?

Combos:

1. 1 physical x 8 cores
   
2. 2 physical x 4 cores
   
3. 4 phsicals x 2 cores
   

Is it better to use max number of sockets (physical CPUs), which means combo #3 is better choice?

Or is it better to maximize use of cores/CPU, which means combo #1 is better choice?

thanks

Charles

[a_p_]

From what I read so far there's no difference - regarding ESXi performance and/or CPU scheduling - in how the vCPUs are presented to the guests. The main reason for this feature is to be able to assign more vCPUs to guests which only support a limited number of "physical" processors. There may be some differences in how the guest OS treats the CPUs though, however I'm currently not aware of any.

André