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SQL Server Memory Nodes - NUMA - Lock pages allocation only allocated on 1 node???

  • February 21, 2014 at 8:12 am

    #282776

    Hello All

    Can someone explain why (using DBCC Memorystatus) I can see that all my locked pages allocation is allocated to Memory Node 1 and none is allocated to Memory Node 0?

    Will this affect performance with foreign page costs etc?

    See DBCC Memorystatus output below:

    Memory Manager

    VM Reserved280830968

    VM Committed3542648

    Locked Pages Allocated176826880

    Reserved Memory1024

    Reserved Memory In Use0

    Memory Node Id = 0

    VM Reserved14912

    VM Committed14472

    Locked Pages Allocated0

    MultiPage Allocator12872

    SinglePage Allocator12854120

    Memory Node Id = 1

    VM Reserved280812408

    VM Committed3524636

    Locked Pages Allocated176826880

    MultiPage Allocator1915904

    SinglePage Allocator12854304

  • February 21, 2014 at 9:08 am

    #1691191

    This link seems to answer the question

    http://blogs.msdn.com/b/psssql/archive/2009/05/15/how-it-works-dbcc-memorystatus-locked-pages-allocated-and-singlepageallocator-values.aspx

    .....The buffer pool has a single clerk to track BPool activity so all locked pages and reserved values are accounted for using a single clerk. The NUMA node where the BPool class is initialized will own the clerk and it appears that all the allocations took place on a single node.

    The output below appears to show that all the allocations are taking place on node id = 1. The SinglePage Allocator also shows the same value for all nodes. There is a single (SPA) single page allocator that works with the buffer pool so this value is reported the same across all nodes as well.

    ....

    There is nothing in the memory status to show the real breakdown of the BPool (hashed) pages and such for indicating the foreign aspect. This comes from the performance counters. The following query will show the Target Pages, Total pages and Foreign pages for each node. (Taken from my single NUMA system.)

    select * from sys.dm_os_performance_counters

    where object_name like '%Buffer Node%'

    Conclusion

    Use the SQL Server performance counters to determine the foreign and target memory distribution across NUMA nodes.

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