COP 4600 Operating Systems Fall 2010 Dan C. Marinescu Office: HEC 304 Office hours: Tu-Th 3:30-4:30 PM

Lecture 25 – Tuesday November 16, 2010 Last time: Presentation of the paper “Commodity OS on scalable multiprocessors” by E. Bugnion Today: Thread coordination: multiple senders – multiple receivers Scheduling Scheduling Algorithms Next Time Performance Lecture 25

Single sender and single receiver Lecture 25

Multiple sender –multiple receiver Lecture 25

Lecture 25

Scheduling algorithms Scheduling  assigning jobs to machines. A schedule S  a plan on how to process N jobs using one or machines. Scheduling in the general case in a NP complete problem. A job 1 <= j <- N is characterized by Ci S  completion time of job j under schedule S pi  processing time ri  release time; the time when the job is available for processing di  due time ; the time when the job should be completed. ui =0 if Ci S <= di and ui =1 otherwise Lj = Ci S - di  lateness A schedule S is characterized by The makespan Cmax = max Ci S Average completion time Lecture 25

General description of a scheduling algorithm Lecture 25