Note : Question one is compulsory. Answer any three from
the rest.
1. (i) Consider the execution of the following code
segment. Use Bernstein's condition to detect the maximum
parallelism embedded in this code. Justify the portion
that can be executed is parallel and the remaining portion
that must be executed sequentially.
S1 : A = B + C
S2 : C = D + E
S3 : F = G + E
S4 : C = A + F
S5 : M = G + G
S6 : A = L + C
S7 : A = E + A
(ii) Draw a dependence graph to show all the dependences
for the above code segment.
(iii) Answer the following questions:
(a) Distinguish between single threaded and multithreaded
processor architecture.
(b) What difficulties will arise when a computer is
scaled to become a-massively parallel processing (MPP)
system.
(c) Explain the differences between superscalar and
very large instruction word (VLIW) architectures in
terms of hardware and s/w requirements.
(d) Describe the advantages and short-comings of daisy-chaining
scheme for bus arbitration in a multiprocessor system.
(e) Plot the graph showing the speedup factors and
optimal number of pipeline stages for a linear pipeline
unit. What are the pros and cons?
2 Explain the following terms:
(a) Private cache vs Shared cache
(b) Ring and chordal rings
(c) Hardwired vs Microcoded control.
(d) Network partitioning for multicasting communication.
(e) HIT ratio.
3. (i) What are the two approaches to interleaved memory
organization? What is its significance? Draw a complete
eight-way high order interleaving diagram. Also explain
what are the major and minor cycles for pipelined access
and how these two are related?
(ii) What is the architectural distinction between
RISC and CISC processors? Explain the concept of overlapping
register windows in the SPARC architecture diagrammatically?
4. Distinguish among the following:
(i) Data flow and reduction computers
(ii) Coarse grain and medium grain level parallelism
(iii) Numeric processing and symbolic processing computers
in terms of common operations, memory requirements and
processor architecture.
5. Answer the following questions as applied to multiprocessors
and multicomputers: [15]
(a) Buffering flow control using virtual cut through
routing
(b) Blocking flow control in wormhole routing
(c) Virtual networks and sub networks
6. Answer the following questions:
(i) What is the purpose of prefetch buffers in instruction
pipelining?
(ii) What is the cache coherence problem? What are
the cache inconsistencies resulting from it? Give a
solution to this problem?
(iii) What are the tradeoffs in scalability analysis?
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