Other Memory Functions; Memory Interleave - NEC Express 5800 User Manual

Other Memory Functions

The server memory has the interleaving function in addition to the above RAS functions.

Memory Interleave

The memory interleaving function is one of technologies that speed up data transfer of memory,
and is an approach to speed up by reading and writing from/into multiple memory banks
simultaneously.
The server can always perform memory interleaving in each memory controller. In addition, it can
perform among multiple memory controllers or among multiple processors.
Set Memory Interleave from "Memory Interleave" in Web Console when using memory
interleaving among multiple memory controllers or among multiple processors.
Settings
Disable
Intra
Inter(4way)
Inte(Max)
Refer to "2.5.5 Mode Settings" of "Server Web Console" section for details on the settings.
When using memory interleaving among multiple processors, the memory accesses to the
consecutive area may become faster because multiple processors can access to those areas
parallelly. However, the performance does not simply improve in proportion to the number of
processors due to the controller overhead and discontinuous access to the address.
If there are many memory accesses via different processor, the performance may become lower.
When using the memory interleaving among multiple processors, the performance may become
lower if the NUMA,Non Uniform Memory Access, is set to "enable" on BIOS setup. So, it is
recommended that NUMA is set to "disable" on BIOS when using the memory interleaving
among multiple processors. Refer to the "Chipset" of "BIOS Setup" section for details on NUMA.
Restrictions for each model
 In A1080a-S/A1080a-D/A1040a it is recommended that memory capacity between memory
controllers that interleaves are the same.
In each memory
Controller
Interleaving
Interleaving
Interleaving
Interleaving
Among multiple memory
Controllers
NOT Interleaving
Interleaving
Interleaving
Interleaving
99
Hardware
Among multiple
Processors
NOT Interleaving
NOT Interleaving
Interleaving(max 4ways)
Interleaving(full ways)