Multiprocessor

What does Multiprocessor mean?

A multiprocessor is a computer system with two or more central processing units (CPUs), with each one sharing the common main memory as well as the peripherals. This helps in simultaneous processing of programs.

The key objective of using a multiprocessor is to boost the system’s execution speed, with other objectives being fault tolerance and application matching.

A good illustration of a multiprocessor is a single central tower attached to two computer systems. A multiprocessor is regarded as a means to improve computing speeds, performance and cost-effectiveness, as well as to provide enhanced availability and reliability.

Techopedia explains Multiprocessor

In multiprocessing, all CPUs may have equal functions or some may be reserved for specific functions.

Different ways of using a multiprocessor include:

• As a uniprocessor, such as single instruction, single data (SISD)
• Inside a single system for executing multiple, individual series of instructions in multiple perspectives, such as multiple instruction, multiple data (MIMD)
• A single series of instructions in various perspectives, such as single instruction, multiple data (SIMD), which is usually used for vector processing
• Multiple series of instructions in a single perspective, such as multiple instruction, single data (MISD), which is used for redundancy in failsafe systems and, occasionally, for describing hyper-threading or pipelined processors

Benefits of using a multiprocessor include:

• Enhanced performance
• Multiple applications
• Multiple users
• Multi-tasking inside an application
• High throughput and/or responsiveness
• Hardware sharing among CPUs

Communication architecture of a multiprocessor:

• Message Passing
• Independent address space for every processor
• Processor communication by means of message passing
• Processors include private memories
• Concentrates attention on high-priced, non-local operations


• Shared Memory
• Processor communication is done by means of a shared address space
• Processor communication is done by means of shared memory read/write
• Convenient on small-scale devices
• Lower latency
• Non-uniform memory access (NUMA) or symmetric multiprocessing (SMP)