Comments on: SQL Server IO handling mechanism can be severely affected by high CPU usage http://blog.sqlworkshops.com/sql-server-io-handling-mechanism-can-be-severely-affected-by-high-cpu-usage/ Microsoft SQL Server Performance Monitoring & Tuning Thu, 19 Jul 2012 11:24:59 +0000 hourly 1 http://wordpress.org/?v=3.5.1 By: R Meyyappan http://blog.sqlworkshops.com/sql-server-io-handling-mechanism-can-be-severely-affected-by-high-cpu-usage/#comment-3 R Meyyappan Wed, 18 Jul 2012 15:59:54 +0000 http://blog.sqlworkshops.com/?p=73#comment-3 Hello Kennie, thanks for your suggestion. Unfortunately, dedicating a single CPU only for IO using an affinity mask like you mention will not help solve this problem. Did you test it?

See comments from Randy Rabin and Marco Carozzi to the connect item: https://connect.microsoft.com/SQLServer/feedback/details/744650/sql-server-io-handling-mechanism-can-be-severely-affected-by-high-cpu-usage. Randy’s feedback: Setting CPU and I/O affinity masks to separate the different workloads onto different CPUs had no effect (I was hoping it would). Even with one CPU allocated to processing and 3 CPUs to I/O, there was still a big difference in query performance.

Regards
-ramesh-

]]> By: Kennie Nybo Pontoppidan http://blog.sqlworkshops.com/sql-server-io-handling-mechanism-can-be-severely-affected-by-high-cpu-usage/#comment-2 Kennie Nybo Pontoppidan Mon, 04 Jun 2012 09:11:19 +0000 http://blog.sqlworkshops.com/?p=73#comment-2 you could consider dedicating a single cpu only for IO using an affinity mask. I sat in a workshop in MOW2012 where Thomas Kejser described this very problem. You might want to consult him for the details

Best wishes,
Kennie

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