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From: calton@cs.columbia.edu (Calton Pu)
Newsgroups: comp.os.research
Subject: TR available (Fine-Grain Scheduling)
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Date: 31 Oct 88 22:57:21 GMT
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[ TR -- not to me!  --DL                                                    ]

Technical Report No. CUCS-381-88 

Title:          Fine-Grain Scheduling

                        Abstract

We introduce the concept of fine-grain scheduling.  Conventional
scheduling makes job assignment an exclusive function of time.  We
broaden the meaning of the term ``scheduling'' to include job
assignment as a function of any stream of interrupts as a reference
frame, not just timer interrupts.  By fine-grain we mean frequent
checking and scheduling actions (e.g. at sub-millisecond
intervals), introducing new flexibility into scheduling.  We have
implemented fine-grain scheduling in the Synthesis operating system
based on a software mechanism similar to phase locked loop.  Very low
overhead context switches and scheduling cost (a few microseconds on a
68020-based machine) makes Synthesis fine-grain scheduling practical.
Interesting applications of fine-grain scheduling include I/O device
management, real-time scheduling, highly sensitive adaptive
scheduling, and distributed adaptive scheduling.


by:             Henry Massalin and Calton Pu

                Department of Computer Science 
                Columbia University
                New York, NY 10027


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