D02.06. FMS NUMAParameter NUMAFX

FMS NUMA Parameter NUMAFX

Data Type

Integer

Default Value

48, Compaq GS series

11, SGI Origin series.

DESCRIPTION:

This parameter specifies how the compute and I/O threads are bound to processors. The options are:

0
Do not bind threads.
+1
Bind compute threads to individual processors.
+2
Bind I/O threads to individual processors.
+4
Place the parent on the target processor before starting the thread. On some systems, this is required to locate the stack and data segments of the new thread on the target CPU.
+8
Request is mandatory (SGI only).
+16
Bind the compute threads to their appropriate node.
+32
Bind the I/O threads to their appropriate node.

These options provide an essential part of the NUMA technology. They provide the link between what memory is addressed by each thread and where the memory is located.

Two choices are available for binding threads. One choice binds the threads to specific CPU's. This has the advantage of assuring that maximum reuse of the cache will occur, even if a thread is interrupted by an I/O process.

The second choice binds the threads to the node. This allows the threads to be scheduled on any processor on the node. This allows the I/O and CPU threads to make maximum use of the compute resources on the node. However, if the thread looses it's affinity for the processor and is rescheduled on another processor, additional cache loads will result.

FMS distributes the I/O threads uniformly among the nodes.