Modular Approach to Multi-resource Arbiter Design

2014 20th IEEE International Symposium on Asynchronous Circuits and Systems

Garside

et al. 2014

Abstract-Asynchronous circuits have been used to implement Networks-on-Chip (NoCs), resulting in asynchronous NoCs where the links are usually implemented as quasi-delay-insensitive (QDI) pipelines to tolerate delay variations. With the ageing process of circuits, permanent faults may happen on links at runtime, causing both data errors and deadlocks of the network. This paper presents an asynchronous Spatial Division Multiplexing (SDM) NoC which tolerates permanent faults on the QDI links. Using a time-out mechanism, a general fault-detection technique can locate the permanent fault in the deadlocked NoC. To recover the network, a Drain&Release technique releases faultfree network resources on the deadlocked path. The SDM NoC physically divides every link and buffer into multiple independent virtual circuits. By configuring the switch allocator, the faulty virtual circuit is blocked so that it will not be allocated to any packets. The succeeding traffic requesting the same link will go through other fault-free virtual circuits and the network function is recovered. With regard to intermittent faults, the previously blocked virtual circuit can be resumed when the fault disappears. Experimental results show the asynchronous SDM NoC can detect and recover from permanent faults with reasonable overhead.

Section: A Time-out Mechanism Detecting the Permanent Faultmentioning

confidence: 99%

“…Fig. 12 shows a multi-resource arbiter [9], [18] used to implement the switch allocator where two requests compete for one of the two resources (i.e. output virtual circuits).…”

Section: Blocking the Faulty Virtual Circuitmentioning

confidence: 99%

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An Asynchronous SDM Network-on-Chip Tolerating Permanent Faults

Zhang

2014 20th IEEE International Symposium on Asynchronous Circuits and Systems

Garside

et al. 2014

“…Traditional asynchronous arbiters, such as the MUTEX-NET arbiter [25,22], the tree arbiter [26] and the ring arbiter [27], are capable of allocating only one resource to multiple clients. The only two allocators that allocate multiple resources to multiple clients are the virtual channel admission controller (VAVC) presented in QNoC [22] and the multi-resource arbiter [28,29,30]. The VAVC allocator treats all clients fairly but resources are selected by an unbalanced static priority arbiter (SPA) [31].…”

Section: Switch Allocatormentioning

confidence: 99%

Asynchronous spatial division multiplexing router

Microprocessors and Microsystems

Edwards

2011

Asynchronous quasi-delay-insensitive (QDI) NoCs have several advantages over their clocked counterparts.Virtual channel (VC) is the most utilized flow control method in asynchronous routers but spatial division multiplexing (SDM) achieves better throughput performance for best effort traffic than VC. A novel asynchronous SDM router architecture is presented. Area and latency models are provided to analyse the network performance of all router architectures including wormhole, virtual channel and SDM. Performance comparisons have been made with different configurations of payload size, communication distance, buffer size, port bandwidth, network size and number of VCs/virtual circuits. Compared with VC, SDM achieves higher throughput with lower area overhead.

“…channel admission control presented in QNoC [20] and the multi-resource arbiter [25]- [27]. The virtual channel admission control treats all clients fairly but resources are selected by an unbalanced static priority arbiter [28].…”

Section: Fig 13: Stg Of a 2x2 M-n Match Allocatormentioning

confidence: 99%

Routing of asynchronous Clos networks

IET Comput. Digit. Tech.

Edwards

Zuo

et al. 2011

Abstract-Clos networks provide the theoretically optimal solution to build high-radix switches. Dynamically reconfiguring a three-stage Clos network is more difficult in asynchronous circuits than in synchronous circuits. This paper proposes a novel asynchronous dispatching (AD) algorithm for general three-stage Clos networks. It is compared with the classic synchronous concurrent round-robin dispatching (CRRD) algorithm in unbuffered Clos networks. The AD algorithm avoids the contention in central modules (CMs) using a state feedback scheme and outperforms the throughput of CRRD in behavioural simulations.Two asynchronous Clos networks using the AD algorithm are implemented and compared with a synchronous Clos network using the CRRD algorithm. The asynchronous Clos scheduler is smaller than its synchronous counterpart. Synchronous Clos networks achieve higher throughput than asynchronous Clos networks because asynchronous Clos networks cannot hide the arbitration latency and their data paths are slow. The asynchronous Clos scheduler consumes significantly lower power than the synchronous scheduler and the asynchronous Clos network using bundled-data data switches shows the best power efficiency in all implementations.