Characteristics of multiprocessors - Computer Science Engineering (CSE) PDF Download

Characteristics of multiprocessors

• A multiprocessor system is an interconnection of two or more CPUs with memory and input-output equipment.
• The term “processor” in multiprocessor can mean either a central processing unit (CPU) or an input-output processor (IOP).
• Multiprocessors are classified as multiple instruction stream, multiple data stream (MIMD) systems
• The similarity and distinction between multiprocessor and multicomputer are
  • Similarity
    • Both support concurrent operations
  • Distinction
    • The network consists of several autonomous computers that may or may not communicate with each other.
    • A multiprocessor system is controlled by one operating system that provides interaction between processors and all the components of the system cooperate in the solution of a problem.

• Multiprocessing improves the reliability of the system.
• The benefit derived from a multiprocessor organization is an improved system performance.
  • Multiple independent jobs can be made to operate in parallel.
  •  A single job can be partitioned into multiple parallel tasks.
• Multiprocessing can improve performance by decomposing a program into parallel executable tasks.
  • The user can explicitly declare that certain tasks of the program be executed in parallel.
    • This must be done prior to loading the program by specifying the parallel executable segments.
  • The other is to provide a compiler with multiprocessor software that can automatically detect parallelism in a user’s program.
• Multiprocessor are classified by the way their memory is organized.
  • A multiprocessor system with common shared memory is classified as a shared-memory or tightly coupled multiprocessor.
    • Tolerate a higher degree of interaction between tasks.
  • Each processor element with its own private local memory is classified as a distributed-memory or loosely coupled system. 
    • Are most efficient when the interaction between tasks is minimal