It seems you have to edit the registry to expose this (be careful)
Click Start, click Run, type regedit, and then click OK.
Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\PerfProc\Performance
- Click Start, click Run, type regedit, and then click OK.
- Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\PerfProc\Performance
- On the Edit menu, click New, and then click DWORD Value.
- Right-click New Value #1, click Rename, and then type ProcessNameFormat to name the new value
- Right-click ProcessNameFormat, and then click Modify.
- In the Data value box, type one of the following values, and then click OK:
- 1: Disables PID data. This value is the default value.
- 2: Enables PID data.
- Exit Registry Editor.
This solves the problem that you had where They're in the format w3wp#1, w3wp#2, w3wp#3
and now will be in the format
They will now have the PID in the format like so w3wp3865, w3wp2325, w3wp2154
and you can add a performance counter for what your looking for explicitly as you asked w3wp3865
https://blogs.technet.microsoft.com/askperf/2010/03/29/perfmon-identifying-processes-by-pid-instead-of-instance/
As an alternative, sysinternals perfmon.exe should be able to get performance information (if not more) without altering the registry. But I am not sure If its the exact details you need.