现代操作系统全套配套课件4eTanenbaumPPT及教学资料Chapter02-Processes and Threads.ppt

The Producer-Consumer Problem with Message Passing (2) Figure 2-36. The producer-consumer problem with N messages. Tanenbaum Bo,Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, Inc. All rights reserved. Barriers Figure 2-37. Use of a barrier. (a) Processes approaching a barrier. (b) All processes but one blocked at the barrier. (c) When the last process arrives at the barrier, all of them are let through. Tanenbaum Bo,Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, Inc. All rights reserved. Avoiding Locks: Read-Copy-Update (1) Figure 2-38. Read-Copy-Update: inserting a node in the tree and then removing a branch—all without locks Tanenbaum Bo,Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, Inc. All rights reserved. Avoiding Locks: Read-Copy-Update (2) Figure 2-38. Read-Copy-Update: inserting a node in the tree and then removing a branch—all without locks Tanenbaum Bo,Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, Inc. All rights reserved. Introduction to SchedulingProcess Behavior Figure 2-39. Bursts of CPU usage alternate with periods of waiting for I/O. (a) A CPU-bound process. (b) An I/O-bound process. Tanenbaum Bo,Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, Inc. All rights reserved. Categories of Scheduling Algorithms Batch. Interactive. Real time. Tanenbaum Bo,Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, Inc. All rights reserved. Scheduling Algorithm Goals Figure 2-40. Some goals of the scheduling algorithm under different circumstances. Tanenbaum Bo,Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, Inc. All rights reserved. Scheduling in Batch Systems First-Come First-Served Shortest Job First Shortest Remaining Time Next Tanenbaum Bo,Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, Inc. All rights reserved. Shortest Job First Figure 2-41. An example of shortest job first scheduling. (a) Running four jobs in the original order. (b) Running them in sh