Hello @Wei Zhao ,
Thank you for reaching out to the Microsoft Q&A platform. Happy to answer your question.
I see you are referring to the usage of compute specific resource quota as highlighted below. This usage is nothing but number of vCPU cores allocated to each of the virtual machines that are created under this subscription of size standard B2 SKU for example.
You could check for the virtual machines blade with the filters shown in below screenshot as to know which VMs are using vCPUs under each size of VM. All the vCPU across the specific VM SKU sums up to the usage of vCPUs quota for each family size consumption shown in the above Usage+Quota blade
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