System\Context Switches/Sec on windows server 2008 r2 with ms sql server

If you're specifically looking hunting for things in SQL Server, you can use:

select 
	* 
from 
	sys.dm_os_tasks as OT
		left join sys.dm_exec_sessions as ES on OT.session_id = ES.session_id
		inner join sys.dm_exec_requests as ER on OT.session_id = ER.session_id
		outer apply fn_get_sql( ER.sql_handle ) as SQL
order by
	context_switches_count desc;

Select allOpen in new window

That's going to give you a lot of columns back for results, you can pick and choose what you want, but it will attempt to give you the text of the executing query that has large amount of context switches on each session thread.  Context switches are a tricky little thing, however.  What they are, is when the kernel switches the processor from one thread to another.  This is going to occur.  I would usually combine context switching with other metrics (ie. CPU Utilization, etc).  Is this alarm coming from the sql server or the esx host ?

Also, take a look at the context switching category of this fellow: http://www.sqlserverfaq.net/2011/01/31/what-perfmon-counters-should-i-monitor-and-what-each-of-them-mean/

Is your CPU on that VM constantly high? then I would look deeper into that but if it's not then just raise the threshold in your monitoring tool.

"Understanding Context Switching"
http://technet.microsoft.com/en-us/library/ms191296(v=sql.105).aspx


"Performance impact: driving up context switches/sec"
http://sqlblog.com/blogs/linchi_shea/archive/2012/01/12/performance-impact-driving-up-context-switches-sec.aspx

Padawan, thank you for suggestion, will give it a try, although the same happens on SQL server which is not in use (please see bellow).

Notifications/alerts are coming from a separate monitoring system (NetCrunch). The thing is that we are observing this on all SQL servers that we have (i.e. higher values of context switching). Even on the server which is a test server and doesn't have any databases which would be in use - it still generates quite high values of context switching.

Icohan, thank you for the links. CPU load is averaging at about 10% on test SQL server VM. Context Switch delta (as observed via Process Explorer) is highest on two processes: Interupts (2000 - 3000) and System Idle Process (2000 - 10000).

Because there was no good answer for me.