LogP machine explained

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

, , and .

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:

, the latency of the communication medium. , the overhead of sending and receiving a message. , 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. , 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

, and are measured in multiples of processor cycles.

See also

• Bulk synchronous parallel
• Parallel programming model

Notes and References

1. Culler et al. 1993