3 research outputs found
Architectures for dependable modern microprocessors
Η εξέλιξη των ολοκληρωμένων κυκλωμάτων σε συνδυασμό με τους αυστηρούς χρονικούς
περιορισμούς καθιστούν την επαλήθευση της ορθής λειτουργίας των επεξεργαστών
μία εξαιρετικά απαιτητική διαδικασία. Με κριτήριο το στάδιο του κύκλου ζωής
ενός επεξεργαστή, από την στιγμή κατασκευής των πρωτοτύπων και έπειτα, οι
τεχνικές ελέγχου ορθής λειτουργίας διακρίνονται στις ακόλουθες κατηγορίες: (1)
Silicon Debug: Τα πρωτότυπα ολοκληρωμένα κυκλώματα ελέγχονται εξονυχιστικά, (2)
Manufacturing Testing: ο τελικό ποιοτικός έλεγχος και (3) In-field
verification: Περιλαμβάνει τεχνικές, οι οποίες διασφαλίζουν την λειτουργία του
επεξεργαστή σύμφωνα με τις προδιαγραφές του. Η διδακτορική διατριβή προτείνει
τα ακόλουθα: (1) Silicon Debug: Η εργασία αποσκοπεί στην επιτάχυνση της
διαδικασίας ανίχνευσης σφαλμάτων και στον αυτόματο εντοπισμό τυχαίων
προγραμμάτων που δεν περιέχουν νέα -χρήσιμη- πληροφορία σχετικά με την αίτια
ενός σφάλματος. Η κεντρική ιδέα αυτής της μεθόδου έγκειται στην αξιοποίηση της
έμφυτης ποικιλομορφίας των αρχιτεκτονικών συνόλου εντολών και στην δυνατότητα
από-διαμόρφωσης τμημάτων του κυκλώματος, (2) Manufacturing Testing: προτείνεται
μία μέθοδο για την βελτιστοποίηση του έλεγχου ορθής λειτουργίας των
πολυνηματικών και πολυπύρηνων επεξεργαστών μέσω της χρήση λογισμικού
αυτοδοκιμής, (3) Ιn-field verification: Αναλύθηκε σε βάθος η επίδραση που έχουν
τα μόνιμα σφάλματα σε μηχανισμούς αύξησης της απόδοσης. Επιπρόσθετα, προτάθηκαν
τεχνικές για την ανίχνευση και ανοχή μόνιμων σφαλμάτων υλικού σε μηχανισμούς
πρόβλεψης διακλάδωσης.Technology scaling, extreme chip integration and the compelling requirement to
diminish the time-to-market window, has rendered microprocessors more prone to
design bugs and hardware faults. Microprocessor validation is grouped into the
following categories, based on where they intervene in a microprocessor’s
lifecycle: (a) Silicon debug: the first hardware prototypes are exhaustively
validated, (b) Μanufacturing testing: the final quality control during massive
production, and (c) In-field verification: runtime error detection techniques
to guarantee correct operation. The contributions of this thesis are the
following: (1) Silicon debug: We propose the employment of deconfigurable
microprocessor architectures along with a technique to generate self-checking
random test programs to avoid the simulation step and triage the redundant
debug sessions, (2) Manufacturing testing: We propose a self-test optimization
strategy for multithreaded, multicore microprocessors to speedup test program
execution time and enhance the fault coverage of hard errors; and (3) In-field
verification: We measure the effect of permanent faults performance components.
Then, we propose a set of low-cost mechanisms for the detection, diagnosis and
performance recovery in the front-end speculative structures. This thesis
introduces various novel methodologies to address the validation challenges
posed throughout the life-cycle of a chip
Nova combinação de hardware e de software para veículos de desporto automóvel baseada no processamento directo de funções gráficas
Doutoramento em Engenharia EletrónicaThe main motivation for the work presented here began with previously
conducted experiments with a programming concept at the time named
"Macro". These experiments led to the conviction that it would be possible to
build a system of engine control from scratch, which could eliminate many of
the current problems of engine management systems in a direct and intrinsic
way. It was also hoped that it would minimize the full range of software and
hardware needed to make a final and fully functional system.
Initially, this paper proposes to make a comprehensive survey of the state of
the art in the specific area of software and corresponding hardware of
automotive tools and automotive ECUs. Problems arising from such software
will be identified, and it will be clear that practically all of these problems stem
directly or indirectly from the fact that we continue to make comprehensive use
of extremely long and complex "tool chains". Similarly, in the hardware, it will
be argued that the problems stem from the extreme complexity and
inter-dependency inside processor architectures. The conclusions are
presented through an extensive list of "pitfalls" which will be thoroughly
enumerated, identified and characterized.
Solutions will also be proposed for the various current issues and for the
implementation of these same solutions. All this final work will be part of a
"proof-of-concept" system called "ECU2010". The central element of this
system is the before mentioned "Macro" concept, which is an graphical block
representing one of many operations required in a automotive system having
arithmetic, logic, filtering, integration, multiplexing functions among others. The
end result of the proposed work is a single tool, fully integrated, enabling the
development and management of the entire system in one simple visual
interface. Part of the presented result relies on a hardware platform fully
adapted to the software, as well as enabling high flexibility and scalability in
addition to using exactly the same technology for ECU, data logger and
peripherals alike.
Current systems rely on a mostly evolutionary path, only allowing online
calibration of parameters, but never the online alteration of their own
automotive functionality algorithms. By contrast, the system developed and
described in this thesis had the advantage of following a "clean-slate"
approach, whereby everything could be rethought globally. In the end, out of all
the system characteristics, "LIVE-Prototyping" is the most relevant feature,
allowing the adjustment of automotive algorithms (eg. Injection, ignition,
lambda control, etc.) 100% online, keeping the engine constantly working,
without ever having to stop or reboot to make such changes. This consequently
eliminates any "turnaround delay" typically present in current automotive
systems, thereby enhancing the efficiency and handling of such systems.A principal motivação para o trabalho que conduziu a esta tese residiu na
constatação de que os actuais métodos de modelação de centralinas
automóveis conduzem a significativos problemas de desenvolvimento e
manutenção. Como resultado dessa constatação, o objectivo deste trabalho
centrou-se no desenvolvimento de um conceito de arquitectura que rompe
radicalmente com os modelos state-of-the-art e que assenta num conjunto de
conceitos que vieram a ser designados de "Macro" e "Celular ECU". Com este
modelo pretendeu-se simultaneamente minimizar a panóplia de software e de
hardware necessários à obtenção de uma sistema funcional final.
Inicialmente, esta tese propõem-se fazer um levantamento exaustivo do
estado da arte na área específica do software e correspondente hardware das
ferramentas e centralinas automóveis. Os problemas decorrentes de tal
software serão identificados e, dessa identificação deverá ficar claro, que
praticamente todos esses problemas têm origem directa ou indirecta no facto
de se continuar a fazer um uso exaustivo de "tool chains" extremamente
compridas e complexas. De forma semelhante, no hardware, os problemas
têm origem na extrema complexidade e inter-dependência das arquitecturas
dos processadores. As consequências distribuem-se por uma extensa lista de
"pitfalls" que também serão exaustivamente enumeradas, identificadas e
caracterizadas.
São ainda propostas soluções para os diversos problemas actuais e
correspondentes implementações dessas mesmas soluções. Todo este
trabalho final faz parte de um sistema "proof-of-concept" designado
"ECU2010". O elemento central deste sistema é o já referido conceito de
“Macro”, que consiste num bloco gráfico que representa uma de muitas
operações necessárias num sistema automóvel, como sejam funções
aritméticas, lógicas, de filtragem, de integração, de multiplexagem, entre
outras. O resultado final do trabalho proposto assenta numa única ferramenta,
totalmente integrada que permite o desenvolvimento e gestão de todo o
sistema de forma simples numa única interface visual. Parte do resultado
apresentado assenta numa plataforma hardware totalmente adaptada ao
software, bem como na elevada flexibilidade e escalabilidade, para além de
permitir a utilização de exactamente a mesma tecnologia quer para a
centralina, como para o datalogger e para os periféricos.
Os sistemas actuais assentam num percurso maioritariamente evolutivo,
apenas permitindo a calibração online de parâmetros, mas nunca a alteração
online dos próprios algoritmos das funcionalidades automóveis. Pelo contrário,
o sistema desenvolvido e descrito nesta tese apresenta a vantagem de seguir
um "clean-slate approach", pelo que tudo pode ser globalmente repensado. No
final e para além de todas as restantes características, o
“LIVE-PROTOTYPING” é a funcionalidade mais relevante, ao permitir alterar
algoritmos automóveis (ex: injecção, ignição, controlo lambda, etc.) de forma
100% online, mantendo o motor constantemente a trabalhar e sem nunca ter
de o parar ou re-arrancar para efectuar tais alterações. Isto elimina
consequentemente qualquer "turnaround delay" tipicamente presente em
qualquer sistema automóvel actual, aumentando de forma significativa a
eficiência global do sistema e da sua utilização