How to point out high CPU Utilization in sql server 2008

Question

Hi,
I am using sql server 2008 , where in i have 10 instances in the physical box of all sql server 2008 versions.
I can see , the CPU (12 CPUS) that is allocated to the physical box is consuming around 90% of utilization, I need your help to point out the exact sql instance that is using more CPU, Please give me the mathods , since i understand that there is no fixed
rule to derive the solution.
Thank you
hemadri

Answer 1

This first thing to check if CPU is at 100% is to look for parallel queries:
-- Tasks running in parallel (filtering out MARS requests below):
select * from sys.dm_os_tasks as t
 where t.session_id in (
   select t1.session_id
    from sys.dm_os_tasks as t1
   group by t1.session_id
  having count(*) > 1
  and min(t1.request_id) = max(t1.request_id));
-- Requests running in parallel:
 select *
   from sys.dm_exec_requests as r
   join (
           select t1.session_id, min(t1.request_id)
          from sys.dm_os_tasks as t1
         group by t1.session_id
        having count(*) > 1
           and min(t1.request_id) = max(t1.request_id)
      ) as t(session_id, request_id)
     on r.session_id = t.session_id
    and r.request_id = t.request_id;
Best Regards,Uri Dimant SQL Server MVP,
http://sqlblog.com/blogs/uri_dimant/
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