Question # 1 (Marks 30)
a) Give the routing algorithm for a ring
b) Use part (a) as a subroutine & hence give the routing algorithm for k-
d mesh (with wrap around)
c) For a 3-D (no wrap) mesh (row x column x depth )= p x q r & p>q>r;
Find the link cost, diameter & bisection width of this mesh
Question # 2 (Marks 30)
A 3 processor (P1, P2, P3) SMP system has implemented MESI cache
coherent protocol. Give operation, state and cache block contents in each
processor cache memory and main memory. Use dirty bit and least recently
used block replacement policy for main memory write back. Main memory
has 4 cache blocks and processor cache memory has two cache blocks.
Initial contents of the main memory
Processor P2 reads Q.
Processor P3 reads R.
Processor P1 reads L.
Processor P3 reads U.
Processor P2 writes 9 in Q.
Processor P1 writes 10 in L.
Processor P3 writes 7 in U.
Processor P3 writes 8 in R.
Processor P3 reads P.
S
4
L
U
6
5
P
1
R
Q
3
2
Cache block 1
Cache block 2
Cache block 3
Cache block 4
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