78 research outputs found
Memory built-in self-repair and correction for improving yield: a review
Nanometer memories are highly prone to defects due to dense structure, necessitating memory built-in self-repair as a must-have feature to improve yield. Today’s system-on-chips contain memories occupying an area as high as 90% of the chip area. Shrinking technology uses stricter design rules for memories, making them more prone to manufacturing defects. Further, using 3D-stacked memories makes the system vulnerable to newer defects such as those coming from through-silicon-vias (TSV) and micro bumps. The increased memory size is also resulting in an increase in soft errors during system operation. Multiple memory repair techniques based on redundancy and correction codes have been presented to recover from such defects and prevent system failures. This paper reviews recently published memory repair methodologies, including various built-in self-repair (BISR) architectures, repair analysis algorithms, in-system repair, and soft repair handling using error correcting codes (ECC). It provides a classification of these techniques based on method and usage. Finally, it reviews evaluation methods used to determine the effectiveness of the repair algorithms. The paper aims to present a survey of these methodologies and prepare a platform for developing repair methods for upcoming-generation memories
A machine learning-based approach to optimize repair and increase yield of embedded flash memories in automotive systems-on-chip
Nowadays, Embedded Flash Memory cores occupy a significant portion of Automotive Systems-on-Chip area, therefore strongly contributing to the final yield of the devices. Redundancy strategies play a key role in this context; in case of memory failures, a set of spare word- and bit-lines are allocated by a replacement algorithm that complements the memory testing procedure. In this work, we show that replacement algorithms, which are heavily constrained in terms of execution time, may be slightly inaccurate and lead to classify a repairable memory core as unrepairable. We denote this situation as Flash memory false fail. The proposed approach aims at identifying false fails by using a Machine Learning approach that exploits a feature extraction strategy based on shape recognition. Experimental results carried out on the manufacturing data show a high capability of predicting false fails
Fault and Defect Tolerant Computer Architectures: Reliable Computing With Unreliable Devices
This research addresses design of a reliable computer from unreliable device technologies. A system architecture is developed for a fault and defect tolerant (FDT) computer. Trade-offs between different techniques are studied and yield and hardware cost models are developed. Fault and defect tolerant designs are created for the processor and the cache memory. Simulation results for the content-addressable memory (CAM)-based cache show 90% yield with device failure probabilities of 3 x 10(-6), three orders of magnitude better than non fault tolerant caches of the same size. The entire processor achieves 70% yield with device failure probabilities exceeding 10(-6). The required hardware redundancy is approximately 15 times that of a non-fault tolerant design. While larger than current FT designs, this architecture allows the use of devices much more likely to fail than silicon CMOS. As part of model development, an improved model is derived for NAND Multiplexing. The model is the first accurate model for small and medium amounts of redundancy. Previous models are extended to account for dependence between the inputs and produce more accurate results
Conception et test des circuits et systèmes numériques à haute fiabilité et sécurité
Research activities I carried on after my nomination as Chargé de Recherche deal with the definition of methodologies and tools for the design, the test and the reliability of secure digital circuits and trustworthy manufacturing. More recently, we have started a new research activity on the test of 3D stacked Integrated CIrcuits, based on the use of Through Silicon Vias. Moreover, thanks to the relationships I have maintained after my post-doc in Italy, I have kept on cooperating with Politecnico di Torino on the topics related to test and reliability of memories and microprocessors.Secure and Trusted DevicesSecurity is a critical part of information and communication technologies and it is the necessary basis for obtaining confidentiality, authentication, and integrity of data. The importance of security is confirmed by the extremely high growth of the smart-card market in the last 20 years. It is reported in "Le monde Informatique" in the article "Computer Crime and Security Survey" in 2007 that financial losses due to attacks on "secure objects" in the digital world are greater than $11 Billions. Since the race among developers of these secure devices and attackers accelerates, also due to the heterogeneity of new systems and their number, the improvement of the resistance of such components becomes today’s major challenge.Concerning all the possible security threats, the vulnerability of electronic devices that implement cryptography functions (including smart cards, electronic passports) has become the Achille’s heel in the last decade. Indeed, even though recent crypto-algorithms have been proven resistant to cryptanalysis, certain fraudulent manipulations on the hardware implementing such algorithms can allow extracting confidential information. So-called Side-Channel Attacks have been the first type of attacks that target the physical device. They are based on information gathered from the physical implementation of a cryptosystem. For instance, by correlating the power consumed and the data manipulated by the device, it is possible to discover the secret encryption key. Nevertheless, this point is widely addressed and integrated circuit (IC) manufacturers have already developed different kinds of countermeasures.More recently, new threats have menaced secure devices and the security of the manufacturing process. A first issue is the trustworthiness of the manufacturing process. From one side, secure devices must assure a very high production quality in order not to leak confidential information due to a malfunctioning of the device. Therefore, possible defects due to manufacturing imperfections must be detected. This requires high-quality test procedures that rely on the use of test features that increases the controllability and the observability of inner points of the circuit. Unfortunately, this is harmful from a security point of view, and therefore the access to these test features must be protected from unauthorized users. Another harm is related to the possibility for an untrusted manufacturer to do malicious alterations to the design (for instance to bypass or to disable the security fence of the system). Nowadays, many steps of the production cycle of a circuit are outsourced. For economic reasons, the manufacturing process is often carried out by foundries located in foreign countries. The threat brought by so-called Hardware Trojan Horses, which was long considered theoretical, begins to materialize.A second issue is the hazard of faults that can appear during the circuit’s lifetime and that may affect the circuit behavior by way of soft errors or deliberate manipulations, called Fault Attacks. They can be based on the intentional modification of the circuit’s environment (e.g., applying extreme temperature, exposing the IC to radiation, X-rays, ultra-violet or visible light, or tampering with clock frequency) in such a way that the function implemented by the device generates an erroneous result. The attacker can discover secret information by comparing the erroneous result with the correct one. In-the-field detection of any failing behavior is therefore of prime interest for taking further action, such as discontinuing operation or triggering an alarm. In addition, today’s smart cards use 90nm technology and according to the various suppliers of chip, 65nm technology will be effective on the horizon 2013-2014. Since the energy required to force a transistor to switch is reduced for these new technologies, next-generation secure systems will become even more sensitive to various classes of fault attacks.Based on these considerations, within the group I work with, we have proposed new methods, architectures and tools to solve the following problems:• Test of secure devices: unfortunately, classical techniques for digital circuit testing cannot be easily used in this context. Indeed, classical testing solutions are based on the use of Design-For-Testability techniques that add hardware components to the circuit, aiming to provide full controllability and observability of internal states. Because crypto‐ processors and others cores in a secure system must pass through high‐quality test procedures to ensure that data are correctly processed, testing of crypto chips faces a dilemma. In fact design‐for‐testability schemes want to provide high controllability and observability of the device while security wants minimal controllability and observability in order to hide the secret. We have therefore proposed, form one side, the use of enhanced scan-based test techniques that exploit compaction schemes to reduce the observability of internal information while preserving the high level of testability. From the other side, we have proposed the use of Built-In Self-Test for such devices in order to avoid scan chain based test.• Reliability of secure devices: we proposed an on-line self-test architecture for hardware implementation of the Advanced Encryption Standard (AES). The solution exploits the inherent spatial replications of a parallel architecture for implementing functional redundancy at low cost.• Fault Attacks: one of the most powerful types of attack for secure devices is based on the intentional injection of faults (for instance by using a laser beam) into the system while an encryption occurs. By comparing the outputs of the circuits with and without the injection of the fault, it is possible to identify the secret key. To face this problem we have analyzed how to use error detection and correction codes as counter measure against this type of attack, and we have proposed a new code-based architecture. Moreover, we have proposed a bulk built-in current-sensor that allows detecting the presence of undesired current in the substrate of the CMOS device.• Fault simulation: to evaluate the effectiveness of countermeasures against fault attacks, we developed an open source fault simulator able to perform fault simulation for the most classical fault models as well as user-defined electrical level fault models, to accurately model the effect of laser injections on CMOS circuits.• Side-Channel attacks: they exploit physical data-related information leaking from the device (e.g. current consumption or electro-magnetic emission). One of the most intensively studied attacks is the Differential Power Analysis (DPA) that relies on the observation of the chip power fluctuations during data processing. I studied this type of attack in order to evaluate the influence of the countermeasures against fault attack on the power consumption of the device. Indeed, the introduction of countermeasures for one type of attack could lead to the insertion of some circuitry whose power consumption is related to the secret key, thus allowing another type of attack more easily. We have developed a flexible integrated simulation-based environment that allows validating a digital circuit when the device is attacked by means of this attack. All architectures we designed have been validated through this tool. Moreover, we developed a methodology that allows to drastically reduce the time required to validate countermeasures against this type of attack.TSV- based 3D Stacked Integrated Circuits TestThe stacking process of integrated circuits using TSVs (Through Silicon Via) is a promising technology that keeps the development of the integration more than Moore’s law, where TSVs enable to tightly integrate various dies in a 3D fashion. Nevertheless, 3D integrated circuits present many test challenges including the test at different levels of the 3D fabrication process: pre-, mid-, and post- bond tests. Pre-bond test targets the individual dies at wafer level, by testing not only classical logic (digital logic, IOs, RAM, etc) but also unbounded TSVs. Mid-bond test targets the test of partially assembled 3D stacks, whereas finally post-bond test targets the final circuit.The activities carried out within this topic cover 2 main issues:• Pre-bond test of TSVs: the electrical model of a TSV buried within the substrate of a CMOS circuit is a capacitance connected to ground (when the substrate is connected to ground). The main assumption is that a defect may affect the value of that capacitance. By measuring the variation of the capacitance’s value it is possible to check whether the TSV is correctly fabricated or not. We have proposed a method to measure the value of the capacitance based on the charge/ discharge delay of the RC network containing the TSV.• Test infrastructures for 3D stacked Integrated Circuits: testing a die before stacking to another die introduces the problem of a dynamic test infrastructure, where test data must be routed to a specific die based on the reached fabrication step. New solutions are proposed in literature that allow reconfiguring the test paths within the circuit, based on on-the-fly requirements. We have started working on an extension of the IEEE P1687 test standard that makes use of an automatic die-detection based on pull-up resistors.Memory and Microprocessor Test and ReliabilityThanks to device shrinking and miniaturization of fabrication technology, performances of microprocessors and of memories have grown of more than 5 magnitude order in the last 30 years. With this technology trend, it is necessary to face new problems and challenges, such as reliability, transient errors, variability and aging.In the last five years I’ve worked in cooperation with the Testgroup of Politecnico di Torino (Italy) to propose a new method to on-line validate the correctness of the program execution of a microprocessor. The main idea is to monitor a small set of control signals of the processors in order to identify incorrect activation sequences. This approach can detect both permanent and transient errors of the internal logic of the processor.Concerning the test of memories, we have proposed a new approach to automatically generate test programs starting from a functional description of the possible faults in the memory.Moreover, we proposed a new methodology, based on microprocessor error probability profiling, that aims at estimating fault injection results without the need of a typical fault injection setup. The proposed methodology is based on two main ideas: a one-time fault-injection analysis of the microprocessor architecture to characterize the probability of successful execution of each of its instructions in presence of a soft-error, and a static and very fast analysis of the control and data flow of the target software application to compute its probability of success
Balancing reliability, cost, and performance tradeoffs with FreeFault
Abstract—Memory errors have been a major source of system failures and fault rates may rise even further as memory continues to scale. This increasing fault rate, especially when combined with advent of integrated on-package memories, may exceed the capabilities of traditional fault tolerance mecha-nisms or significantly increase their overhead. In this paper, we present FreeFault as a hardware-only, transparent, and nearly-free resilience mechanism that is implemented entirely within a processor and can tolerate the majority of DRAM faults. FreeFault repurposes portions of the last-level cache for storing retired memory regions and augments a hardware memory scrubber to monitor memory health and aid retirement decisions. Because it relies on existing structures (cache associativity) for retirement/remapping type repair, FreeFault has essentially no hardware overhead. Because it requires a very modest portion of the cache (as small as 8KB) to cover a large fraction of DRAM faults, FreeFault has almost no impact on performance. We explain how FreeFault adds an attractive layer in an overall resilience scheme of highly-reliable and highly-available systems by delaying, and even entirely avoiding, calling upon software to make tradeoff decisions between memory capacity, performance, and reliability. I
Tecniche di Test Innovative per la Caratterizzazione di Memorie a Gate Flottante
L\u2019affidabilit\ue0 nella ritenzione dei dati memorizzati \ue8 una delle problematiche fondamentali delle memorie flash; esse vengono normalmente testate, in produzione con procedure specifiche implementate su ATE (Automated Test Equipments), per rilevare problemi di lettura, programmazione e cancellazione; vengono inoltre provate altre procedure per identificare possibili faults e per il corretto trimming dei parametri interni.
Oggi, il testing classico con ATE \ue8 supportato dalle tecniche BIST (Built-In-Self-Test), tramite le quali si prevede in progetto, all\u2019interno dei circuiti integrati, una parte di hardware e software supplementari per permettere l\u2019auto-test (funzionale e/o parametrico), cos\uec da ridurre la dipendenza da apparecchiature ATE esterne e quindi riducendo sensibilmente il tempo di esecuzione del test completo e permettendo la realizzazione di test del circuito integrato in qualsiasi istante e condizione di funzionamento (in-field test).
Un ulteriore passo avanti nel testing in-field \ue8 stato effettuato con lo sviluppo delle tecniche SBST (Software-Based Self Test), che si basano sull\u2019uso del microprocessore interno alla memoria per effettuare i test necessari via software, senza avere cos\uec la necessit\ue0 di progettare e realizzare nel chip hardware aggiuntivo, cos\uec come accade nel caso di presenza di strutture BIST all\u2019interno del circuito.
Rispetto allo stato dell\u2019arte delle tecniche di testing si \ue8 approfondito lo studio, la progettazione e la realizzazione di una soluzione circuitale innovativa denominata Portable-ATE per il testing dei Memory Test Chip.
La scheda Portable-ATE \ue8 stata sviluppata partendo da una demo-board STM32-Nucleo (STM32F072RB) ed aggiungendo una scheda custom che permette di gestire il sistema di alimentazione, la corretta comunicazione con il memory test chip e l\u2019alloggiamento del test chip stesso. Essa \ue8 in grado di valutare le perfomances di un singolo memory test-chip mantenendo gli stessi standard di affidabilit\ue0 e riproducibilit\ue0 di un ATE classico, aggiungendo portabilit\ue0, flessibilit\ue0, configurabilit\ue0 e la possibilit\ue0 di sviluppo e debug di algoritmi di gestione e software-based self test (SBST) con logging in tempo reale.
Con l\u2019utilizzo del Portable-ATE \ue8 stata effettuata la caratterizzazione di alcuni memory test chip di STMicroelectronics con particolare attenzione alle analisi di stress, quale gate e drain stress e successivamente sono stati effettuati test di ciclatura per verificare la ritenzione dei dati; per valutare i test effettuati sono state estratte le distribuzioni di soglia.
Infine, grazie all\u2019utilizzo del Portable ATE \ue8 stato possibile sviluppare, testare e ottimizzare gli algoritmi di gestione della memoria, program con verify, erase con verify e refresh senza avere all\u2019interno della memoria nessun PEC (Program/Erase Controller) o microprocessore interno per la gestione degli stessi e con la possibilit\ue0, totalmente innovativa, di avere un logging in tempo reale delle operazioni in esecuzione
DRAM Bender: An Extensible and Versatile FPGA-based Infrastructure to Easily Test State-of-the-art DRAM Chips
To understand and improve DRAM performance, reliability, security and energy
efficiency, prior works study characteristics of commodity DRAM chips.
Unfortunately, state-of-the-art open source infrastructures capable of
conducting such studies are obsolete, poorly supported, or difficult to use, or
their inflexibility limit the types of studies they can conduct.
We propose DRAM Bender, a new FPGA-based infrastructure that enables
experimental studies on state-of-the-art DRAM chips. DRAM Bender offers three
key features at the same time. First, DRAM Bender enables directly interfacing
with a DRAM chip through its low-level interface. This allows users to issue
DRAM commands in arbitrary order and with finer-grained time intervals compared
to other open source infrastructures. Second, DRAM Bender exposes easy-to-use
C++ and Python programming interfaces, allowing users to quickly and easily
develop different types of DRAM experiments. Third, DRAM Bender is easily
extensible. The modular design of DRAM Bender allows extending it to (i)
support existing and emerging DRAM interfaces, and (ii) run on new commercial
or custom FPGA boards with little effort.
To demonstrate that DRAM Bender is a versatile infrastructure, we conduct
three case studies, two of which lead to new observations about the DRAM
RowHammer vulnerability. In particular, we show that data patterns supported by
DRAM Bender uncovers a larger set of bit-flips on a victim row compared to the
data patterns commonly used by prior work. We demonstrate the extensibility of
DRAM Bender by implementing it on five different FPGAs with DDR4 and DDR3
support. DRAM Bender is freely and openly available at
https://github.com/CMU-SAFARI/DRAM-Bender.Comment: To appear in TCAD 202
Dynamic partial reconfiguration management for high performance and reliability in FPGAs
Modern Field-Programmable Gate Arrays (FPGAs) are no longer used to implement
small “glue logic” circuitries. The high-density of reconfigurable logic resources in
today’s FPGAs enable the implementation of large systems in a single chip. FPGAs
are highly flexible devices; their functionality can be altered by simply loading a new
binary file in their configuration memory. While the flexibility of FPGAs is
comparable to General-Purpose Processors (GPPs), in the sense that different
functions can be performed using the same hardware, the performance gain that can
be achieved using FPGAs can be orders of magnitudes higher as FPGAs offer the
ability for customisation of parallel computational architectures.
Dynamic Partial Reconfiguration (DPR) allows for changing the functionality of
certain blocks on the chip while the rest of the FPGA is operational. DPR has
sparked the interest of researchers to explore new computational platforms where
computational tasks are off-loaded from a main CPU to be executed using dedicated
reconfigurable hardware accelerators configured on demand at run-time. By having a
battery of custom accelerators which can be swapped in and out of the FPGA at runtime,
a higher computational density can be achieved compared to static systems
where the accelerators are bound to fixed locations within the chip. Furthermore, the
ability of relocating these accelerators across several locations on the chip allows for
the implementation of adaptive systems which can mitigate emerging faults in the
FPGA chip when operating in harsh environments. By porting the appropriate fault
mitigation techniques in such computational platforms, the advantages of FPGAs can
be harnessed in different applications in space and military electronics where FPGAs
are usually seen as unreliable devices due to their sensitivity to radiation and extreme
environmental conditions.
In light of the above, this thesis investigates the deployment of DPR as: 1) a method
for enhancing performance by efficient exploitation of the FPGA resources, and 2) a
method for enhancing the reliability of systems intended to operate in harsh
environments. Achieving optimal performance in such systems requires an efficient
internal configuration management system to manage the reconfiguration and
execution of the reconfigurable modules in the FPGA. In addition, the system needs
to support “fault-resilience” features by integrating parameterisable fault detection
and recovery capabilities to meet the reliability standard of fault-tolerant
applications. This thesis addresses all the design and implementation aspects of an
Internal Configuration Manger (ICM) which supports a novel bitstream relocation
model to enable the placement of relocatable accelerators across several locations on
the FPGA chip. In addition to supporting all the configuration capabilities required to
implement a Reconfigurable Operating System (ROS), the proposed ICM also
supports the novel multiple-clone configuration technique which allows for cloning
several instances of the same hardware accelerator at the same time resulting in much
shorter configuration time compared to traditional configuration techniques. A faulttolerant
(FT) version of the proposed ICM which supports a comprehensive faultrecovery
scheme is also introduced in this thesis. The proposed FT-ICM is designed
with a much smaller area footprint compared to Triple Modular Redundancy (TMR)
hardening techniques while keeping a comparable level of fault-resilience.
The capabilities of the proposed ICM system are demonstrated with two novel
applications. The first application demonstrates a proof-of-concept reliable FPGA
server solution used for executing encryption/decryption queries. The proposed
server deploys bitstream relocation and modular redundancy to mitigate both
permanent and transient faults in the device. It also deploys a novel Built-In Self-
Test (BIST) diagnosis scheme, specifically designed to detect emerging permanent
faults in the system at run-time. The second application is a data mining application
where DPR is used to increase the computational density of a system used to
implement the Frequent Itemset Mining (FIM) problem
Methodology and Ecosystem for the Design of a Complex Network ASIC
Performance of HPC systems has risen steadily. While the 10 Petaflop/s barrier has been breached in the year 2011 the next large step into the exascale era is expected sometime between the years 2018 and 2020. The EXTOLL project will be an integral part in this venture. Originally designed as a research project on FPGA basis it will make the transition to an ASIC to improve its already excelling performance even further. This transition poses many challenges that will be presented in this thesis. Nowadays, it is not enough to look only at single components in a system. EXTOLL is part of complex ecosystem which must be optimized overall since everything is tightly interwoven and disregarding some aspects can cause the whole system either to work with limited performance or even to fail.
This thesis examines four different aspects in the design hierarchy and proposes efficient solutions or improvements for each of them. At first it takes a look at the design implementation and the differences between FPGA and ASIC design. It introduces a methodology to equip all on-chip memory with ECC logic automatically without the user’s input and in a transparent way so that the underlying code that uses the memory does not have to be changed. In the next step the floorplanning process is analyzed and an iterative solution is worked out based on physical and logical constraints of the EXTOLL design. Besides, a work flow for collaborative design is presented that allows multiple users to work on the design concurrently. The third part concentrates on the high-speed signal path from the chip to the connector and how it is affected by technological limitations. All constraints are analyzed and a package layout for the EXTOLL chip is proposed that is seen as the optimal solution. The last part develops a cost model for wafer and package level test and raises technological concerns that will affect the testing methodology. In order to run testing internally it proposes the development of a stand-alone test platform that is able to test packaged EXTOLL chips in every aspect
Innovative Techniques for Testing and Diagnosing SoCs
We rely upon the continued functioning of many electronic devices for our everyday welfare,
usually embedding integrated circuits that are becoming even cheaper and smaller
with improved features. Nowadays, microelectronics can integrate a working computer
with CPU, memories, and even GPUs on a single die, namely System-On-Chip (SoC).
SoCs are also employed on automotive safety-critical applications, but need to be tested
thoroughly to comply with reliability standards, in particular the ISO26262 functional
safety for road vehicles.
The goal of this PhD. thesis is to improve SoC reliability by proposing innovative
techniques for testing and diagnosing its internal modules: CPUs, memories, peripherals,
and GPUs. The proposed approaches in the sequence appearing in this thesis are described
as follows:
1. Embedded Memory Diagnosis: Memories are dense and complex circuits which
are susceptible to design and manufacturing errors. Hence, it is important to understand
the fault occurrence in the memory array. In practice, the logical and physical
array representation differs due to an optimized design which adds enhancements to
the device, namely scrambling. This part proposes an accurate memory diagnosis
by showing the efforts of a software tool able to analyze test results, unscramble
the memory array, map failing syndromes to cell locations, elaborate cumulative
analysis, and elaborate a final fault model hypothesis. Several SRAM memory failing
syndromes were analyzed as case studies gathered on an industrial automotive
32-bit SoC developed by STMicroelectronics. The tool displayed defects virtually,
and results were confirmed by real photos taken from a microscope.
2. Functional Test Pattern Generation: The key for a successful test is the pattern applied
to the device. They can be structural or functional; the former usually benefits
from embedded test modules targeting manufacturing errors and is only effective
before shipping the component to the client. The latter, on the other hand, can be
applied during mission minimally impacting on performance but is penalized due
to high generation time. However, functional test patterns may benefit for having
different goals in functional mission mode. Part III of this PhD thesis proposes
three different functional test pattern generation methods for CPU cores embedded
in SoCs, targeting different test purposes, described as follows:
a. Functional Stress Patterns: Are suitable for optimizing functional stress during
I
Operational-life Tests and Burn-in Screening for an optimal device reliability
characterization
b. Functional Power Hungry Patterns: Are suitable for determining functional
peak power for strictly limiting the power of structural patterns during manufacturing
tests, thus reducing premature device over-kill while delivering high test
coverage
c. Software-Based Self-Test Patterns: Combines the potentiality of structural patterns
with functional ones, allowing its execution periodically during mission.
In addition, an external hardware communicating with a devised SBST was proposed.
It helps increasing in 3% the fault coverage by testing critical Hardly
Functionally Testable Faults not covered by conventional SBST patterns.
An automatic functional test pattern generation exploiting an evolutionary algorithm
maximizing metrics related to stress, power, and fault coverage was employed
in the above-mentioned approaches to quickly generate the desired patterns. The
approaches were evaluated on two industrial cases developed by STMicroelectronics;
8051-based and a 32-bit Power Architecture SoCs. Results show that generation
time was reduced upto 75% in comparison to older methodologies while
increasing significantly the desired metrics.
3. Fault Injection in GPGPU: Fault injection mechanisms in semiconductor devices
are suitable for generating structural patterns, testing and activating mitigation techniques,
and validating robust hardware and software applications. GPGPUs are
known for fast parallel computation used in high performance computing and advanced
driver assistance where reliability is the key point. Moreover, GPGPU manufacturers
do not provide design description code due to content secrecy. Therefore,
commercial fault injectors using the GPGPU model is unfeasible, making radiation
tests the only resource available, but are costly. In the last part of this thesis, we
propose a software implemented fault injector able to inject bit-flip in memory elements
of a real GPGPU. It exploits a software debugger tool and combines the
C-CUDA grammar to wisely determine fault spots and apply bit-flip operations in
program variables. The goal is to validate robust parallel algorithms by studying
fault propagation or activating redundancy mechanisms they possibly embed. The
effectiveness of the tool was evaluated on two robust applications: redundant parallel
matrix multiplication and floating point Fast Fourier Transform
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