Worst-Case Flit and Packet Delay Bounds in Wormhole Networks on Chip

Zhonghai LU
Wenhua DOU

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E92-A    No.12    pp.3211-3220
Publication Date: 2009/12/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E92.A.3211
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on VLSI Design and CAD Algorithms)
Category: Embedded, Real-Time and Reconfigurable Systems
delay bounds,  performance analysis,  network calculus,  network-on-chip,  

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We investigate per-flow flit and packet worst-case delay bounds in on-chip wormhole networks. Such investigation is essential in order to provide guarantees under worst-case conditions in cost-constrained systems, as required by many hard real-time embedded applications. We first propose analysis models for flow control, link and buffer sharing. Based on these analysis models, we obtain an open-ended service analysis model capturing the combined effect of flow control, link and buffer sharing. With the service analysis model, we compute equivalent service curves for individual flows, and then derive their flit and packet delay bounds. Our experimental results verify that our analytical bounds are correct and tight.