This directory contains CSRI technical report #294 entitled:


	Optimizing IPC Performance for Shared-Memory Multiprocessors

	Benjamin Gamsa, Orran Krieger, and Michael Stumm


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     stumm@csri.toronto.edu
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Abstract:

	We assert that in order to perform well, a shared-memory
	multiprocessor inter-process communication (IPC) facility must avoid
	a) accessing any shared data, and b) acquiring any locks.  In
	addition, such a multiprocessor IPC facility must preserve the
	locality and concurrency of the applications themselves so that the
	high performance of the IPC facility can be fully exploited.
	
	In this paper we describe the design and implementation of a new
	shared-memory multiprocessor IPC facility that in the common case
	internally requires no accesses to shared data and no locking.  In
	addition, the model of IPC we support and our implementation ensure
	that local resources are made available to the server to allow it to
	exploit any locality and concurrency available in the service.  To
	the best of our knowledge, this is the first IPC subsystem with
	these attributes.
	
	The performance data we present demonstrates that i) the
	end-to-end performance of our multiprocessor IPC facility is
	competitive with the fastest uniprocessor IPC times, and ii) that
	our implementation can sustain this performance with perfect speedup
	regardless of the degree of concurrency, even if all requests are
	directed to the same server.