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Abstract
Single-core processor architectures
which are widely-used in safety-critical
avionics applications are now becoming
scarce due to the migration of semi-
conductor manufacturers to multi-core
processor architectures. In this article,
the suitability of commercial-off-the-
shelf (COTS) multi-core processor
architectures for safety-critical avionics
applications will be considered, and
the challenges of undertaking avionics
safety-certification will be discussed.
The Challenge of Multi-
core Processor Selection
Over the last decade, in order to
meet the demands of ever increasing
performance from the commercial
market, and faced with the fundamental
performance limit which could be
achieved on a single-core processor
due to clock speed ceiling, semi-
conductor manufacturers transitioned
to multi-core processor architectures
to achieve performance gains.
The introduction ofmulti-core processor
architectures has provided performance
gains for enterprise general purpose
applications; it has also presented
some unique challenges for their use
in safety-critical avionics systems. This
is because avionics applications have
specific requirements, including (but
not limited to) application isolation
and determinism, and these are
not the primary considerations of
semiconductor manufacturers when
designing multi-core processors for the
commercial market.
The avionics industry, academia and
certification authorities have research
projects into the use of multi-core
processor architectures in avionics
applications. A number of researchers
have found that there is variation
between multi-core processor designs
in terms of their suitability for use in
avionics applications, due to the impact
of architectural design features on
application isolation and determinism
[1]. These relate to factors arising
from shared resources on the device,
which include use of a single memory
controller or shared bus is used by
multiple cores (providing a risk of
resource contention), and similarly use
of separate or shared Level 2 caches
per core.
This uncertainty about the selection
of multi-core processors for avionics
programmes, has been compounded
by the following factors:
i)
Although the avionics safety
certification agencies EASA and FAA
have published the MULCORS research
report and the CAST-32 position paper
respectively, on the use of multi-core
processors in avionics, this does not
constitute formal policy or guidance.
ii)
Single-core processors which
have been used in safety-critical
avionics applications are now nearing
the end of silicon availability or are no
longer available [2].
Towards avionics safety certification on multi-
core processor architectures
Paul Parkinson, Wind River
48 l New-Tech Magazine Europe