Algorithm Engineering And Experimentation: International Workshop Alenex'99 Baltimore, Md, Usa, January 15-16, 1999, Selected Papers (lecture Notes In Computer Science)
by Catherine C. McGeoch /
1999 / English / PDF
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Symmetric multiprocessors (SMPs) dominate the high-end server
market and are currently the primary candidate for constructing
large scale multiprocessor systems. Yet, the design of e cient
parallel algorithms for this platform c- rently poses several
challenges. The reason for this is that the rapid progress in
microprocessor speed has left main memory access as the primary
limitation to SMP performance. Since memory is the bottleneck,
simply increasing the n- ber of processors will not necessarily
yield better performance. Indeed, memory bus limitations typically
limit the size of SMPs to 16 processors. This has at least
twoimplicationsfor the algorithmdesigner. First, since there are
relatively few processors availableon an SMP, any parallel
algorithm must be competitive with its sequential counterpart with
as little as one processor in order to be r- evant. Second, for the
parallel algorithm to scale with the number of processors, it must
be designed with careful attention to minimizing the number and
type of main memory accesses. In this paper, we present a
computational model for designing e cient al- rithms for symmetric
multiprocessors. We then use this model to create e cient solutions
to two widely di erent types of problems - linked list pre x com-
tations and generalized sorting. Both problems are memory
intensive, but in die rent ways. Whereas generalized sorting
algorithms typically require a large numberofmemoryaccesses, they
areusuallytocontiguousmemorylocations. By contrast, prex
computation algorithms typically require a more modest qu- tity of
memory accesses, but they are are usually to non-contiguous memory
locations.
Symmetric multiprocessors (SMPs) dominate the high-end server
market and are currently the primary candidate for constructing
large scale multiprocessor systems. Yet, the design of e cient
parallel algorithms for this platform c- rently poses several
challenges. The reason for this is that the rapid progress in
microprocessor speed has left main memory access as the primary
limitation to SMP performance. Since memory is the bottleneck,
simply increasing the n- ber of processors will not necessarily
yield better performance. Indeed, memory bus limitations typically
limit the size of SMPs to 16 processors. This has at least
twoimplicationsfor the algorithmdesigner. First, since there are
relatively few processors availableon an SMP, any parallel
algorithm must be competitive with its sequential counterpart with
as little as one processor in order to be r- evant. Second, for the
parallel algorithm to scale with the number of processors, it must
be designed with careful attention to minimizing the number and
type of main memory accesses. In this paper, we present a
computational model for designing e cient al- rithms for symmetric
multiprocessors. We then use this model to create e cient solutions
to two widely di erent types of problems - linked list pre x com-
tations and generalized sorting. Both problems are memory
intensive, but in die rent ways. Whereas generalized sorting
algorithms typically require a large numberofmemoryaccesses, they
areusuallytocontiguousmemorylocations. By contrast, prex
computation algorithms typically require a more modest qu- tity of
memory accesses, but they are are usually to non-contiguous memory
locations.