Adding and Configuring Components

For best performance, partitions should be either single cell or greater powers of 2: 2, 4, 8, and 16 cells.
Memory interleaving is performed by taking either four or six physical address bits and using them to index into a cell
mapping table entry consisting of 16 or 64 sub-entries. For a single cell partition, each sub-entry is loaded with only one
cell. A two-cell partition alternates between the two cells. There is one 64 sub-entry cell map entry and a 48-16 sub-entry
cell entry.
Partitions that are not powers of two will undergo revisiting. Consecutive accesses will go through all the cell boards and
come back through revisiting as many cells as necessary until all memory is utilized and the 64-entry table is filled.
Table 1, SD 64 Way Partition Configurations, shows configurations that yield the best performance. However, memory
may be left over. This memory is interleaved in the 16-entry tables and does not always yield the best performance.
Depending on the memory configuration and the partition size the memory system performance will always increase,
although not always linearly.
Use the following guidelines when building partitions:
Build the largest partition first.
●
Keep partitions with four cells or less on the same quad. (Slots 0-3, 4-7, 8-11, and 12-15) ●
Keep the amount of memory on each cell in a partition as equal as possible. ●
Fill empty cabinets before adding to a partially populated cabinet. ●
For best performance, partitions should be either single cell or greater powers of 2: 2, 4, 8, and 16 cells. ●
Always check a new partition for bottlenecks with the formula Qx*Qy/Qt/I. See XBC-XBC Link Load Equation
for more information.
●
The partitions in the following table provide good but not always optimum link loading while allowing for growth.
Table 1 SD 64 Way Partition Configurations
#Cells per
partition
Cabinet 0 -Cell Slots Cabinet 1 - Cell Slots
#Cells per
partition
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1 A I E M C K G O B J F N D L H P 16
2 A E A E C G C G B F B F D H D H 8
3 A A A C C C B B B D D D 4
4 A A A A C C C C B B B B D D D D 4
5 A A A A A B B B B B 2
6 A A A A A A B B B B B B 2
7 A A A A A B A B B B B A B B 2
8 A A A A B A B A B B B B A B A B 2
9 A A A A A A A A A 1
10 A A A A A A A A A A 1
11 A A A A A A A A A A A 1
Superdome Configuration
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