Reference Work Entry

Encyclopedia of Algorithms

pp 1784-1788


Rate-Monotonic Scheduling

  • Nathan FisherAffiliated withDepartment of Computer Science, Wayne State University Email author 
  • , SanjoyK. BaruahAffiliated withDepartment of Computer Science, The University of North Carolina


Fixed-priority scheduling Rate-monotonic analysis Real-time systems Static-priority scheduling

Years and Authors of Summarized Original Work

  • 1973; Liu, Layland

Problem Definition

Liu and Layland [11] introduced rate-monotonic scheduling in the context of the scheduling of recurrent real-time processes upon a computing platform comprising a single preemptive processor.

The Periodic Task Model

The periodic task abstraction models real-time processes that make repeated requests for computation. As defined by Liu and Layland [11], each periodic task τi is characterized by an ordered pair of positive real-valued parameters (Ci, Ti), where Ci is the worst-case execution requirement and Ti the period of the task. The requests for computation that are made by task τi (subsequently referred to as jobs that are generated by τi) satisfy the following assumptions:

  1. A1:

    τi’s first job arrives at system start time (assumed to equal time zero), and subsequent jobs arrive every Ti time units, i.e., one job arrives at time instant k × Ti for all integer k ≥ 0.

  2. A2:

    Each job needs to execute for at most C ...

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