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

2. 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

3. Single sender and single receiver
Lecture 25

4. Multiple sender –multiple receiver
Lecture 25

5. Lecture 25

6. 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

7. General description of a scheduling algorithm
Lecture 25