Summary: Object Sharing in Pfair­scheduled Multiprocessor
Systems #
Philip Holman and James H. Anderson
Department of Computer Science
University of North Carolina
Chapel Hill, NC 27599­3175
Phone: (919) 962­1757
Fax: (919) 962­1799
E­mail: {holman, anderson}@cs.unc.edu
December 2001
Abstract
We consider various techniques for implementing shared objects and for accounting for object­
sharing overheads in Pfair­scheduled multiprocessor systems. We primarily focus on the use of lock­free
objects, though some lock­based alternatives are briefly considered as well. Lock­free objects are more
economical for implementing relatively simple objects such as bu#ers, stacks, queues, and lists; locking
techniques are preferable for more complicated objects and for sychronizing accesses to physical devices.
We present schedulability conditions for Pfair­scheduled systems in which lock­free objects are used.
In addition, using shared queues as an example, we show how one can exploit the tight synchrony that
exists in Pfair­scheduled systems to optimize lock­free implementations. We also show that lock­free
object­sharing overheads can be reduced by combining tasks into supertasks; this is because, within a

Source: Anderson, James - Department of Computer Science, University of North Carolina at Chapel Hill

Collections: Computer Technologies and Information Sciences