Sun Netra 1280 Server
 
Sun Fire V1280 Server
 

PLA-Support>Sun Systems>SPARC>Enterprise>SN-SPARC: Exx00
 
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Applies to:

Goal

Solution

Physical bank 0 of each board is composed of 4 1GB dimms (total of 8 1GB dimms). The remaining banks of each board contain 256MB dimms (total of 28 256MB dimms). Total memory: 22 GB.

Here's the Memory Configuration section of the prtdiag output from this configuration:

============================ Memory Configuration ============================

Segment Table:

-----------------------------------------------------------------------
Base Address       Size       Interleave Factor  Contains
-----------------------------------------------------------------------

0x0                8GB               16          BankIDs 0,1,2,3,4,5,8,9,12,13
0x200000000        2GB               4           BankIDs 6,7,10,14
0x280000000        1GB               2           BankIDs 11,15
0x2000000000       8GB               16          BankIDs 32,33,34,35,36,37,40,41,44,45
0x2200000000       2GB               4           BankIDs 38,39,42,46
0x2280000000       1GB               2           BankIDs 43,47

Bank Table:

-----------------------------------------------------------

           Physical Location

ID       ControllerID  GroupID   Size       Interleave Way
-----------------------------------------------------------

0        0             0         2GB             0,4,8,12
1        0             1         512MB           13
2        0             0         2GB             2,6,10,14
3        0             1         512MB           15
4        1             0         512MB           1
5        1             1         512MB           3
8        2             0         512MB           5
9        2             1         512MB           7
12       3             0         512MB           9
13       3             1         512MB           11
6        1             0         512MB           0
7        1             1         512MB           3
10       2             0         512MB           1
14       3             0         512MB           2
11       2             1         512MB           0
15       3             1         512MB           1
32       8             0         2GB             0,4,8,12
33       8             1         512MB           13
34       8             0         2GB             2,6,10,14
35       8             1         512MB           15
36       9             0         512MB           1
37       9             1         512MB           3
40       10            0         512MB           5
41       10            1         512MB           7
44       11            0         512MB           9
45       11            1         512MB           11
38       9             0         512MB           0
39       9             1         512MB           3
42       10            0         512MB           1
46       11            0         512MB           2
43       10            1         512MB           0
47       11            1         512MB           1

Notice that the minimum size an individual logical bank is 512 MB (a logical bank is formed by one side of the double-sided dimms of each physical bank), interleaving will be configured using a memory chunk of 512 MB. Max interleave is 16-way therefore, 8GB is the maximum size of a memory interleave.

Starting from base-address 0x0, first 8 GB 16 way interleaved are achieved using a total of 16 chunks from logical banks IDs 0,1,2,3,4,5,8,9,12,13 (as shown in the segment table section, 4^th column) as follows:

- first 512MB chunk on logical bank 0 of memory-controller 0

     (that is, Bank ID 0 from above)

The order is readable from the column interleave way (5^th colum of the bank table)

- second chunk on logical bank 0 of memory-controller 1

    (that is, Bank ID 4 at prtdiag)

- third chunk on logical bank 1 on memory-controller 0

    (that is, Bank ID 2 at prtdiag)

- fourth chunk on logical bank 1 on memory-controller 1

    (that is, Bank ID 3 at prtdiag)

- fifth chunk again on logical bank 0 of memory-controller 0

    (that is Bank ID 0 at prtdiag)

That happens because logical bank 0 is 2 GB in size (and contains enough space for four 512MB chunks), so it is 4 times bigger than the other logical banks, and therefore there are still free chunks to map.

This explains why the Interleave Way field in the Bank Table for Bank ID 0 contains 4 chunk numbers the logical bank is mapped into four 512MB chunks during interleave mapping.

Mapping continues in this fashion until the segment reaches 16 chunks, and, in this case, a size of 8GB.

At this point, we must start a new interleave (remember, 16-way is the largest interleave we can create), and a new segment, base-address 0x200000000. On SB0, we still have 6 512MB chunks left to work with (Bank IDs 6, 7, 10, 11, 14, and 15). Interleaves must be constructed in numbers of chunks that are powers of 2, so the remaining chunks are automatically configured into 2 interleaves and segments: one a 4-way interleave and the other a 2-way interleave.

4way:

- first 512MB chunk on Bank ID 6

- second 512MB chunk on Bank ID 7

- third 512MB chunk on Bank ID 10

- fourth 512MB chunk on Bank ID 14

2 way:

- first 512MB chunk on Bank ID 11

- second 512MB chunk on Bank ID 15

That's how interleaving is configured on SB0 in this example, and how to read it from prtdiag. The same process occurs for SB2, and is read in the same fashion.

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