Multiprocessor scheduling
Encyclopedia
In computer science
, multiprocessor scheduling is an NP-complete
optimization problem. The problem statement is: "Given a set J of jobs where job ji has length li and a number of processors mi, what is the minimum possible time required to schedule all jobs in J on m processors such that none overlap?" The applications of this problem are numerous, but are, as suggested by the name of the problem, most strongly associated with the scheduling
of computational tasks in a multiprocessor
environment.
Computer science
Computer science or computing science is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems...
, multiprocessor scheduling is an NP-complete
NP-complete
In computational complexity theory, the complexity class NP-complete is a class of decision problems. A decision problem L is NP-complete if it is in the set of NP problems so that any given solution to the decision problem can be verified in polynomial time, and also in the set of NP-hard...
optimization problem. The problem statement is: "Given a set J of jobs where job ji has length li and a number of processors mi, what is the minimum possible time required to schedule all jobs in J on m processors such that none overlap?" The applications of this problem are numerous, but are, as suggested by the name of the problem, most strongly associated with the scheduling
Scheduling (computing)
In computer science, a scheduling is the method by which threads, processes or data flows are given access to system resources . This is usually done to load balance a system effectively or achieve a target quality of service...
of computational tasks in a multiprocessor
Multiprocessor
Computer system having two or more processing units each sharing main memory and peripherals, in order to simultaneously process programs.Sometimes the term Multiprocessor is confused with the term Multiprocessing....
environment.
Algorithms
A simple, often-used algorithm is the LPT algorithm (Longest Processing Time) which sorts the jobs by its processing time and then assigns them to the machine with the earliest end time so far. This algorithm achieves an upper bound of 4/3 - 1/(3m) OPT.See also
- Job shop schedulingJob Shop SchedulingJob shop scheduling is an optimization problem in computer science in which ideal jobs are assigned to resources at particular times. The most basic version is as follows:...
, a similar problem for scheduling jobs on machines. Some variants of multiprocessor scheduling and job shop scheduling are equivalent problems.