LogP machine

The LogP machine is a model for parallel computation.^[1] It aims at being more practical than the PRAM model while still allowing for easy analysis of computation. The name is not related to the mathematical logarithmic function: Instead, the machine is described by the four parameters $L$ , $o$ , $g$ and $P$ .

The LogP machine consists of arbitrarily many processing units with distributed memory. The processing units are connected through an abstract communication medium which allows point-to-point communication. This model is pair-wise synchronous and overall asynchronous.

The machine is described by the four parameters:

$L$ , the latency of the communication medium.
$o$ , the overhead of sending and receiving a message.
$g$ , the gap required between two send/receive operations. A more common interpretation of this quantity is as the inverse of the bandwidth of a processor-processor communication channel.
$P$ , the number of processing units. Each local operation on each machine takes the same time ('unit time'). This time is called a processor cycle.

The units of the parameters $L$ , $o$ and $g$ are measured in multiples of processor cycles.

Notes

↑ Culler et al. 1993

References

Culler, David; Karp, Richard; Patterson, David; Sahay, Abhijit; Schauser, Klaus Erik; Santos, Eunice; Subramonian, Ramesh; Von Eicken, Thorsten (July 1993), "LogP: Towards a realistic model of parallel computation" (PDF), ACM SIGPLAN Notices, 28 (7): 1–12, doi:10.1145/173284.155333

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LogP machine

See also

Notes

References