OperatingSystemsCh6Process Scheduling1
Operating Systems Ch6 Process Scheduling 1
OutlineUserSpaceProcessProcessProcessKernelSpaceSchedulingAlgProcessSchedulellifecycle11ProcessCommunication&ProcessSchedulingSynchronizationntelContext-Core"i7switching
Outline 2 Process Communication & Synchronization Process Scheduling Scheduler Contextswitching Process Process Process Kernel Space User Space P P P Scheduling Alg Process lifecycle
Whyschedulingis needed· Process execution-Consistsof acycleof CPUexecutionand I/OwaitCPU burst +I/o burst160140120CPUburstdurationKouenbauy100806040200164082432burstduration (milliseconds)3
Why scheduling is needed • Process execution – Consists of a cycle of CPU execution and I/O wait – CPU burst + I/O burst 3 CPU burst duration
Why scheduling is neededQuestion.Howto improveCPUMultiprogrammingutilization(CPUismuchfasterthanI/O)?MultitaskingQuestion.Howtoimprovesystemresponsiveness (interactiveapplications)?A system may contain many processes which are at differentstates (ready for running, waiting for I/O)Scheduling is required because the number of computingresource-the CPU-islimited4
Why scheduling is needed 4 A system may contain many processes which are at different states (ready for running, waiting for I/O) Multiprogramming Question. How to improve CPU utilization (CPU is much faster than I/O)? Question. How to improve system responsiveness (interactive applications)? Multitasking Scheduling is required because the number of computing resource – the CPU – is limited
Topics- Process lifecycle- Process scheduling- Context switching- Scheduling criteria- Scheduling algorithms: Applications/Scenarios(intel)Core"i75
5 Topics - Process lifecycle - Process scheduling - Context switching - Scheduling criteria - Scheduling algorithms - Applications/Scenarios