Hey there!
Understanding the mapping of VM's vCPUs to the host's physical or logical CPUs can be quite valuable, especially when troubleshooting performance or fine-tuning your environment.
To see this mapping in ESXi:
ESXTOP: This is your go-to tool. Connect to your host using SSH and run esxtop.
Press c for the CPU view.
Identify your VM by its World ID.
The column PCPU USED% and PCPU UTIL% will tell you on which physical CPU the VM's vCPU is running.
vCenter Performance Charts:
Select the VM in question.
Navigate to the "Performance" tab and then to "Advanced".
Choose 'Chart Options' and under 'CPU', select the metric 'Core Utilization'. This will give you an idea of which core the vCPUs are utilizing.
However, do note that ESXi employs a CPU scheduler which dynamically schedules vCPUs to run on any available physical CPU (pCPU) core, depending on the current load and other factors. This means the mapping isn't static and can change over time as the scheduler deems necessary.
For in-depth examination or if you're looking into CPU affinity settings (which I'd advise caution with), VMware's official documentation or the VMware communities would be a great place to dive deeper.
Hope this gives you a good starting point!
Best,
Ansar