Fundamental Results for a Generic Implementation of Barriers using Optical Interconnects

TL;DR

This paper establishes fundamental bounds and requirements for implementing barriers in on-chip optical and RF networks, highlighting the necessity of memory counts and broadcast messages, and showing how electing a coordinator can reduce messaging overhead.

Contribution

It provides theoretical bounds and fundamental results on message complexity and storage for barrier implementation using futuristic optical and RF interconnects.

Findings

Maintaining a count of at least N in memory is necessary.

Broadcasting the barrier ID at least once is required.

Electing a coordinator reduces message complexity by a factor of O(N).

Abstract

In this report, we report some fundamental results and bounds on the number of messages and storage required to implement barriers using futuristic on-chip optical and RF networks. We prove that it is necessary to maintain a count to at least N (number of threads) in memory, broadcast the barrier id at least once, and if we elect a co-ordinator, we can reduce the number of messages by a factor of O(N ).