Interconnect architectures for dynamically partially reconfigurable systems
Date
2017
Authors
Bui, Thanh Thi Thanh
Editors
Advisors
Phillips, Braden Jace
Liebelt, Michael J.
Liebelt, Michael J.
Journal Title
Journal ISSN
Volume Title
Type:
Theses
Citation
Statement of Responsibility
Conference Name
Abstract
Dynamically partially reconfigurable FPGAs (Field-Programmable Gate Arrays) allow
hardware modules to be placed and removed at runtime while other parts of the system
keep working. With their potential benefits, they have been the topic of a great
deal of research over the last decade. To exploit the partial reconfiguration capability of
FPGAs, there is a need for efficient, dynamically adaptive communication infrastructure
that automatically adapts as modules are added to and removed from the system.
Many bus and network-on-chip (NoC) architectures have been proposed to exploit this
capability on FPGA technology. However, few realizations have been reported in the
public literature to demonstrate or compare their performance in real world applications.
While partial reconfiguration can offer many benefits, it is still rarely exploited in practical
applications. Few full realizations of partially reconfigurable systems in current
FPGA technologies have been published. More application experiments are required to
understand the benefits and limitations of implementing partially reconfigurable systems
and to guide their further development. The motivation of this thesis is to fill this
research gap by providing empirical evidence of the cost and benefits of different interconnect
architectures. The results will provide a baseline for future research and will
be directly useful for circuit designers who must make a well-reasoned choice between
the alternatives.
This thesis contains the results of experiments to compare different NoC and bus interconnect
architectures for FPGA-based designs in general and dynamically partially
reconfigurable systems. These two interconnect schemes are implemented and evaluated
in terms of performance, area and power consumption using FFT (Fast Fourier
Transform) andANN(Artificial Neural Network) systems as benchmarks. Conclusions
drawn from these results include recommendations concerning the interconnect approach
for different kinds of applications. It is found that a NoC provides much better
performance than a single channel bus and similar performance to a multi-channel bus
in both parallel and parallel-pipelined FFT systems. This suggests that a NoC is a better choice for systems with multiple simultaneous communications like the FFT. Bus-based
interconnect achieves better performance and consume less area and power than NoCbased
scheme for the fully-connected feed-forward NN system. This suggests buses
are a better choice for systems that do not require many simultaneous communications
or systems with broadcast communications like a fully-connected feed-forward NN.
Results from the experiments with dynamic partial reconfiguration demonstrate that
buses have the advantages of better resource utilization and smaller reconfiguration
time and memory than NoCs. However, NoCs are more flexible and expansible. They
have the advantage of placing almost all of the communication infrastructure in the
dynamic reconfiguration region. This means that different applications running on the
FPGA can use different interconnection strategies without the overhead of fixed bus
resources in the static region.
Another objective of the research is to examine the partial reconfiguration process and
reconfiguration overhead with current FPGA technologies. Partial reconfiguration allows
users to efficiently change the number of running PEs to choose an optimal powerperformance
operating point at the minimum cost of reconfiguration. However, this
brings drawbacks including resource utilization inefficiency, power consumption overhead
and decrease in system operating frequency. The experimental results report a
50% of resource utilization inefficiency with a power consumption overhead of less
than 5% and a decrease in frequency of up to 32% compared to a static implementation.
The results also show that most of the drawbacks of partial reconfiguration implementation
come from the restrictions and limitations of partial reconfiguration design flow.
If these limitations can be addressed, partial reconfiguration should still be considered
with its potential benefits.
School/Discipline
School of Electrical and Electronic Engineering
Dissertation Note
Thesis (Ph.D.) -- University of Adelaide, School of Electrical and Electronic Engineering, 2018
Provenance
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