Hitachi 1000 manual Full interleave mode and non-interleave mode

•Full interleave mode (or SMP mode) — Intended for use with an OS without support for the NUMA architecture or with inadequate support for NUMA. In full interleave mode, main memory is interleaved between CPU modules in units. Since memory accesses do not concentrate on one CPU module in full interleave mode, memory bus bottlenecks are less likely and latency is averaged across CPUs.

•Non-interleave mode — This mode specifies the ratio of local memory at a constant rate. Use non- interleave mode with an OS that supports NUMA. In non-interleave mode, memory is not interleaved between CPU modules. An OS supporting NUMA performs process scheduling and memory allocation so that memory accesses by processors only take place within the subject node (CPU module). An OS with APIs for NUMA also allows applications running on it to perform optimization, taking advantage of node-localized memory accesses and enabling higher system performance.

Figure 8. Full interleave mode and non-interleave mode

•Mixture mode — This mode specifies the ratio of a local memory at a constant rate. There can be some restrictions on the ratio of local memory, according to the NUMA function support level of operating system in use. Figure 9 shows examples of all three types of modes.

4GB

CPU Module CPU Module CPU Module CPU Module

#0	#1	#2	#3
Memory	Memory	Memory	Memory
8GB	8GB	8GB	8GB
			Interleave boundary local memory 100.0%
0-1	1-1	2-1	3-1
			Interleave boundary local memory 50.0%
0-0	1-0	2-0	3-0
			Interleave boundary local memory0%
Shows segment of memory

Interleave boundary local memory0%

Interleave boundary local memory Interleave boundary local memory 100.0%

0-0	1-0 2-0	3-0
		4 node
		interleave

	3-1
	2-1	no interleaved
	1-1
		(local
	0-1
0-0	1-0 2-0	3-0
		4 node
		interleave

3-1
2-1	no interleaved
	(local memory)
1-1
0-1

Figure 9. Examples of interleaving

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