Sun Microsystems Sun Fire V480, Руководство администратора

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34 Sun Fire V480 Server Administration Guide • February 2002
Memory Interleaving
You can maximize the system’s memory bandwidth by taking advantage of its
memory interleaving capabilities. Sun Fire V480 systems support two-way, four-way,
and eight-way memory interleaving. In most cases, higher interleaving factors result
in greater system performance. However, actual performance results may vary
depending on the system application.
The system’s interleaving capabilities are summarized as follows:
■
Memory interleaving is limited to memory within the same CPU/Memory board.
Memory is not interleaved across CPU/Memory boards.
■
Eight-way interleaving occurs automatically when all 16 DIMM slots in a
CPU/Memory board are filled with identical capacity DIMMs (16 identical
DIMMs).
■
Four-way interleaving occurs automatically between any two DIMM groups that
are configured identically (eight identical capacity DIMMs).
■
Two-way interleaving occurs automatically in any DIMM group where the DIMM
capacities do not match the capacities used in any other group.
Independent Memory Subsystems
Each Sun Fire V480 CPU/Memory board contains two independent memory
subsystems (one per UltraSPARC III CPU). Memory controller logic incorporated
into the UltraSPARC III CPU allows each CPU to control its own memory
subsystem. One CPU controls DIMM groups A0 and A1, while the other CPU
controls DIMM groups B0 and B1.
The Sun Fire V480 system uses a shared memory architecture. During normal system
operations, the total system memory is shared by all CPUs in the system. However,
in the event of a CPU failure, the two DIMM groups associated with the failed CPU
become unavailable to the other CPUs in the system.
TABLE 3-1
shows the association between the CPUs and their corresponding DIMM
groups.
TABLE 3-1
Association Between CPUs and DIMM Groups
CPU Number CPU/Memory Slot
Associated Local DIMM
Groups
CPU 0 Slot A A0, A1