Active query / tasks running on SQL 2008R2

I have  used the following query to find the currently Running Query on my SQL 2008 R2.

SELECT sqltext.TEXT,
req.session_id,
req.status,
req.command,
req.cpu_time,
req.total_elapsed_time
FROM sys.dm_exec_requests req
CROSS APPLY sys.dm_exec_sql_text(sql_handle) AS sqltext

1. For the session_id, is it equivalent to the sp_id generated from 'sp_who2'. If not, how can I tell who is running the query ?

2. for cpu_time and total_elapsed_time, is it an accumulated value. ie. will it included the value for those completed sql tasks ?

3. for unit used in cpu_time & total_elapsed_time, does it measure in ms & s respectively ?

4. Does the result come from the previous sql statement is the same as the one in the below url ?

http://gallery.technet.microsoft.com/scriptcenter/T-SQL-to-get-various-041b67d3

Tks


Tks