Lec04 - Multiprocessor Scheduling Will consider only shared...

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Computer Science Lecture 4, page CS677: Distributed OS Multiprocessor Scheduling Will consider only shared memory multiprocessor or multi-core CPU Salient features: One or more caches: cache affinity is important Semaphores/locks typically implemented as spin-locks: preemption during critical sections Multi-core systems: some caches shared (L2,L3); others are not 1 Computer Science Lecture 4, page CS677: Distributed OS Multiprocessor Scheduling Central queue – queue can be a bottleneck Distributed queue – load balancing between queue 2
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Lecture 4, page CS677: Distributed OS Scheduling Common mechanisms combine central queue with per processor queue (SGI IRIX) Exploit cache affinity – try to schedule on the same processor that a process/thread executed last Context switch overhead Quantum sizes larger on multiprocessors than uniprocessors 3 Computer Science Lecture 4, page CS677: Distributed OS Distributed Scheduling: Motivation Distributed system with N workstations Model each w/s as identical, independent M/M/1 systems Utilization u , P(system idle)=1- u What is the probability that at least one system is idle and one job is waiting? 4
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This note was uploaded on 11/22/2011 for the course COMPSCI 677 taught by Professor Shenoy during the Spring '08 term at UMass (Amherst).

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Lec04 - Multiprocessor Scheduling Will consider only shared...

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