get-scvirtualmachine : PerfNetworkBytesWrite, PerfNetworkBytesRead,PerfDiskBytesRead,PerfDiskBytesWrite properties not giving correct value

Hi,

I want to retrieve network ingress/egress data and disk transactions for VM configured on SCVMM.

I am using  PerfNetworkBytesWrite, PerfNetworkBytesRead,PerfDiskBytesRead,PerfDiskBytesWrite properties of sc-getvirtualmachine cmdlet for same.

but found that these properties are not returning correct value.

Am I using correct properties?

Is there any other way to achieve this?

Thanks

Pallavi