SQL Server Performance Forum – Threads Archive
UMS scheduler ?
Hi all, What is UMS scheduler ? Where can I get some docs to know about it? Thank youNever heard to UMI Scheduler, where did you get this process is it SQL server related or from any application? I can vaguely remember UMI relates to the handheld devices such as Palm PDA. Satya SKJ
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There are UMS schedulers within SQL Server, User Mode Schedulers, I wonder if this is what the question is about. Tom Pullen
DBA, Oxfam GB
My apologies for the typo, Yes, it is UMS scheduler. Where can I get some reading materials ? Just wondering if it can be tuned from SQLServer side or it is a OS releated process which distributes the CPU resources uniformly for all the applications in the box including SQLServer. Thanks
One of the KBA refers:
UMS – To better understand some of the additional health diagnostics, you must first understand how SQL Server uses a User Mode Scheduling (UMS) Ums.dll helper file. Both SQL Server 7.0 and Microsoft SQL Server 2000 use logical schedulers. These schedulers help to make sure that SQL Server maximizes operating system resource usage in relation to key database action paths. The UMS layer makes sure that SQL Server correctly uses Win32 events to strictly control thread and fiber (or both) scheduling visibility to the operating system. By strictly controlling the threads or fibers that can run, SQL Server can maximize CPU usage as it relates to database primitives such as locking. For example, logical scheduling permits lock waiters to sleep ( WaitForSingleObject on a Win32 event) until the lock owner releases the lock and signals (SetEvent) them to wake up.
Extended Lock Detection
And refer to this linkhttp://builder.com.com/5100-6388_14-5144021-1-1.html for more information.
Satya SKJ
Moderator
http://www.SQL-Server-Performance.Com/forum
This posting is provided “AS IS†with no rights for the sake of knowledge sharing.
Also, the short answer is, you cannot tune them. They’re internal to SQL Server. Tom Pullen
DBA, Oxfam GB
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