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Efficient Synchronization on Multiprocessors with Shared Memory
 ACM Transactions on Programming Languages and Systems
, 1986
"... A new formalism is given for readmodifywrite (RMW) synchronization operations. This formalism is used to extend the memory reference combining mechanism, introduced in the NYU Ultracomputer, to arbitrary RMW operations. A formal correctness proof of this combining mechanism is given. General requi ..."
Abstract

Cited by 84 (2 self)
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A new formalism is given for readmodifywrite (RMW) synchronization operations. This formalism is used to extend the memory reference combining mechanism, introduced in the NYU Ultracomputer, to arbitrary RMW operations. A formal correctness proof of this combining mechanism is given. General requirements for the practicality of combining are discussed. Combining is shown to be practical for many useful memory access operations. This includes memory updates of the form mem_val := mem_val op val, where op need not be associative, and a variety of synchronization primitives. The computation involved is shown to be closely related to parallel prefix evaluation. 1. INTRODUCTION Shared memory provides convenient communication between processes in a tightly coupled multiprocessing system. Shared variables can be used for data sharing, information transfer between processes, and, in particular, for coordination and synchronization. Constructs such as the semaphore introduced by Dijkstra in ...
Combining effects: sum and tensor
"... We seek a unified account of modularity for computational effects. We begin by reformulating Moggi’s monadic paradigm for modelling computational effects using the notion of enriched Lawvere theory, together with its relationship with strong monads; this emphasises the importance of the operations ..."
Abstract

Cited by 30 (4 self)
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We seek a unified account of modularity for computational effects. We begin by reformulating Moggi’s monadic paradigm for modelling computational effects using the notion of enriched Lawvere theory, together with its relationship with strong monads; this emphasises the importance of the operations that produce the effects. Effects qua theories are then combined by appropriate bifunctors on the category of theories. We give a theory for the sum of computational effects, which in particular yields Moggi’s exceptions monad transformer and an interactive input/output monad transformer. We further give a theory of the commutative combination of effects, their tensor, which yields Moggi’s sideeffects monad transformer. Finally we give a theory of operation transformers, for redefining operations when adding new effects; we derive explicit forms for the operation transformers associated to the above monad transformers.