sp_who2 is an Undocumented/Upgraded extension of sp_who.
SP_WHO :
This will provide the following options,
1. System process ID.
2. Status of the process.
3. Login name of the user.
4. Name of the user. I
5. f the process is blocked, the SPID of the blocking process.
6. Database the process is using.
7. Command currently being executed.
SP_WHO2:
Along with the above options, sp_who2 will provide the following additional linformations
1. Total CPU time of each process.
2. Total amount of disk reads for each process.
3. Last time a client called a procedure or executed a query.
4. Application connected.
Cheers,