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what is CPU ? Physical or logical ? Expand / Collapse
Posted Sunday, August 26, 2012 2:16 AM
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When SQL Server runs on a computer with more than one microprocessor or CPU, it detects the best degree of parallelism, that is, the number of processors employed to run a single statement, for each parallel plan execution.

We have a box with 2 CPUs 4 Cores showing 8 logical processors, so , i am not sure how many CPUs for this box, 2 or 8 ?

Post #1350095
Posted Sunday, August 26, 2012 4:38 AM



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8. It's the number visible in task manager in Windows (unless you've configured SQL to use fewer processors)

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

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Post #1350101
Posted Thursday, August 30, 2012 2:51 PM



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2 physical, 8 logical. We can tell the # of each from SQL...

-- cpu overview
SELECT osi.cpu_count AS LogicalCpuCount,
osi.hyperthread_ratio AS HyperthreadCoreRatio,
osi.cpu_count / osi.hyperthread_ratio AS PhysicalCpuCount,
FROM sys.dm_os_schedulers
WHERE scheduler_id < osi.cpu_count
AND is_online = 1
) AS LogicalCpuOnline
FROM sys.dm_os_sys_info osi;

...however not whether the logical CPUs are from multiple cores or from Hyperthreading. In your case you have 2 physical CPUs with 4 cores each and all SQL Server cares about is the logical CPUs when it comes to parallelizing queries, i.e. 8.

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Post #1352505
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