4 research outputs found
Driving the Network-on-Chip Revolution to Remove the Interconnect Bottleneck in Nanoscale Multi-Processor Systems-on-Chip
The sustained demand for faster, more powerful chips has been met by the
availability of chip manufacturing processes allowing for the integration of increasing
numbers of computation units onto a single die. The resulting outcome,
especially in the embedded domain, has often been called SYSTEM-ON-CHIP
(SoC) or MULTI-PROCESSOR SYSTEM-ON-CHIP (MP-SoC).
MPSoC design brings to the foreground a large number of challenges, one of
the most prominent of which is the design of the chip interconnection. With a
number of on-chip blocks presently ranging in the tens, and quickly approaching
the hundreds, the novel issue of how to best provide on-chip communication
resources is clearly felt.
NETWORKS-ON-CHIPS (NoCs) are the most comprehensive and scalable
answer to this design concern. By bringing large-scale networking concepts to
the on-chip domain, they guarantee a structured answer to present and future
communication requirements. The point-to-point connection and packet switching
paradigms they involve are also of great help in minimizing wiring overhead
and physical routing issues. However, as with any technology of recent inception,
NoC design is still an evolving discipline. Several main areas of interest
require deep investigation for NoCs to become viable solutions:
• The design of the NoC architecture needs to strike the best tradeoff among
performance, features and the tight area and power constraints of the onchip
domain.
• Simulation and verification infrastructure must be put in place to explore,
validate and optimize the NoC performance.
• NoCs offer a huge design space, thanks to their extreme customizability in
terms of topology and architectural parameters. Design tools are needed
to prune this space and pick the best solutions.
• Even more so given their global, distributed nature, it is essential to evaluate
the physical implementation of NoCs to evaluate their suitability for
next-generation designs and their area and power costs.
This dissertation performs a design space exploration of network-on-chip architectures,
in order to point-out the trade-offs associated with the design of
each individual network building blocks and with the design of network topology
overall. The design space exploration is preceded by a comparative analysis
of state-of-the-art interconnect fabrics with themselves and with early networkon-
chip prototypes. The ultimate objective is to point out the key advantages
that NoC realizations provide with respect to state-of-the-art communication
infrastructures and to point out the challenges that lie ahead in order to make
this new interconnect technology come true. Among these latter, technologyrelated
challenges are emerging that call for dedicated design techniques at all
levels of the design hierarchy. In particular, leakage power dissipation, containment
of process variations and of their effects. The achievement of the above
objectives was enabled by means of a NoC simulation environment for cycleaccurate
modelling and simulation and by means of a back-end facility for the
study of NoC physical implementation effects. Overall, all the results provided
by this work have been validated on actual silicon layout
Communication centric platforms for future high data intensive applications
The notion of platform based design is considered as a viable solution to boost the
design productivity by favouring reuse design methodology. With the scaling down of
device feature size and scaling up of design complexity, throughput limitations, signal
integrity and signal latency are becoming a bottleneck in future communication centric
System-on-Chip (SoC) design. This has given birth to communication centric platform
based designs.
Development of heterogeneous multi-core architectures has caused the on-chip
communication medium tailored for a specific application domain to deal with multidomain
traffic patterns. This makes the current application specific communication centric
platforms unsuitable for future SoC architectures.
The work presented in this thesis, endeavours to explore the current
communication media to establish the expectations from future on-chip interconnects. A
novel communication centric platform based design flow is proposed, which consists of
four communication centric platforms that are based on shared global bus, hierarchical
bus, crossbars and a novel hybrid communication medium. Developed with a smart
platform controller, the platforms support Open Core Protocol (OCP) socket standard,
allowing cores to integrate in a plug and play fashion without the need to reprogram the
pre-verified platforms. This drastically reduces the design time of SoC architectures. Each
communication centric platform has different throughput, area and power characteristics,
thus, depending on the design constraints, processing cores can be integrated to the most
appropriate communication platform to realise the desired SoC architecture.
A novel hybrid communication medium is also developed in this thesis, which
combines the advantages of two different types of communication media in a single SoC
architecture. The hybrid communication medium consists of crossbar matrix and shared
bus medium . Simulation results and implementation of WiMAX receiver as a real-life
example shows a 65% increase in data throughput than shared bus based communication
medium, 13% decrease in area and 11% decrease in power than crossbar based
communication medium.
In order to automate the generation of SoC architectures with optimised
communication architectures, a tool called SOCCAD (SoC Communication architecture
development) is developed. Components needed for the realisation of the given application
can be selected from the tool’s in-built library. Offering an optimised communication
centric placement, the tool generates the complete SystemC code for the system with
different interconnect architectures, along with its power and area characteristics. The
generated SystemC code can be used for quick simulation and coupled with efficient test
benches can be used for quick verification.
Network-on-Chip (NoC) is considered as a solution to the communication
bottleneck in future SoC architectures with data throughput requirements of over 10GB/s.
It aims to provide low power, efficient link utilisation, reduced data contention and
reduced area on silicon. Current on-chip networks, developed with fixed architectural
parameters, do not utilise the available resources efficiently. To increase this efficiency, a
novel dynamically reconfigurable NoC (drNoC) is developed in this thesis. The proposed
drNoC reconfigures itself in terms of switching, routing and packet size with the changing
communication requirements of the system at run time, thus utilising the maximum
available channel bandwidth. In order to increase the applicability of drNoC, the network
interface is designed to support OCP socket standard. This makes drNoC a highly reuseable
communication framework, qualifying it as a communication centric platform for
high data intensive SoC architectures. Simulation results show a 32% increase in data
throughput and 22-35% decrease in network delay when compared with a traditional NoC
with fixed parameters
Energy-Reliability trade-Off for NoCs
Solutions for combined energy minimization and communication reliability control have to be developed for SoC networks. Redundant encodings and error-resilient protocols create new degrees of freedom for trading off energy against realiability and viceversa. In this chapter, the theoretical framework for energy and reliability analysis is introduced and several error control and recovery strategies are investigated in a realistic SoC setting. Furthermore, the chapter provides guidelines and methods to select the most appropriate error control scheme for a given reliability and/or energy efficiency constraint
Energy-Reliability Trade-Off for NoCs
Networks on Chip presents a variety of topics, problems and approaches with the common theme to systematically organize the on-chip communication in the form of a regular, shared communication network on chip, an NoC for short. As the number of processor cores and IP blocks integrated on a single chip is steadily growing, a systematic approach to design the communication infrastructure becomes necessary. Different variants of packed switched on-chip networks have been proposed by several groups during the past two years. This book summarizes the state of the art of these efforts and discusses the major issues from the physical integration to architecture to operating systems and application interfaces. It also provides a guideline and vision about the direction this field is moving to. Moreover, the book outlines the consequences of adopting design platforms based on packet switched network. The consequences may in fact be far reaching because many of the topics of distributed systems, distributed real-time systems, fault tolerant systems, parallel computer architecture, parallel programming as well as traditional system-on-chip issues will appear relevant but within the constraints of a single chip VLSI implementation. The book is organized in three parts. The first deals with system design and methodology issues. The second presents problems and solutions concerning the hardware and the basic communication infrastructure. Finally, the third part covers operating system, embedded software and application. However, communication from the physical to the application level is a central theme throughout the book. The book serves as an excellent reference source and may be used as a textfor advanced courses on the subject