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Efficient Error Detection Mechanism for 3D-OASIS-Network-on-Chip System
3D-OASIS-NoC flit format
Contents:
Background†
During the past decade, 3D-Network-on-Chips (3D-NoCs) have been showing their advantages against 2D-NoC systems. At the same time, concerns about their reliability have grown as well due to the different kinds of faults that these systems may encounter. Therefore, 3D-NoC must be fault-tolerant to any kind of permanent failure or run-time malfunction. To achieve this goal, a fault-detection scheme is necessary to discover the presence of fault before the propagation of the fault into the entire system and cause the its collapse.
Previously, 3D-Fault-Tolerant-OASIS (3D-FTO) has been designed. 3D-FTO is able to recover from a large number of faults that can occur at links, input-buffers, and crossbar. However in this system, a fault detection mechanism is absent and the diagnosis of faults rely on assuming the presence of faults at a certain period of time. This make the fault recovery less efficient and diminish the reliability of the system.
Problems and Motivation†
In our previous research, a Network Interface (NI) to enhance the reliability of 3D-FTO system was presented. In the
proposed NI, an End-to-End error-detection mechanism based on Cyclic Redundancy Check (CRC) was implemented. However, this mechanism suffers from several problems:
- When using End-to-End detection, the fault occurrence can be detected; however, it cannot be localized. Therefore, the fault diagnosis phase cannot be achieved.
- At the detection of fault, the transmitter NI resends the flits along the same path already detected faulty. Consequently, the resent flit follows the same faulty path; thus, creating a significant latency and power overheads. Furthermore, the flit might not reach its destination, especially when the detected fault is permanent and cannot be recovered.
- In case where a fault occurs at the first hops, it is only detected at the receiving NI. This results in an increasing end-to-end latency since the flit has to travel many hops to the destination and then resent again, even when the fault is in the first hop.
- The previously proposed scheme can detect the presence of fault; but, it cannot recover from it.
- The verification was made using test-benches with small Random-Number-Generator application without using real processors running real applications.
Research goal†
The main goal of this research is to design and implement a fault detection and correction scheme for 3D-Fault-Tolerant-OASIS (3D-FTO). The scheme is based on Error-Detection-Codes (EDC) and Error-Correction-Codes (ECC). It should detect the presence of any kind of errors or malfunction and make the necessary communications with the different modules of 3D-FTO to perform the quick recovery ensuring a graceful performance degradation as less as possible. In addition, the proposed scheme is implemented and tested on a 2x2x2 network using MIPS cores attached to 3D-FTO and running real applications.
Research plan†
Step 1:†
- Understand and run Mr. Ishi's system.
- Read the Multicore book
- Understand 3D-FTO architecture.
Step 2†
- Run on your won machine these 2 tutorials (IN ORDER):
- Akram Ben Ahmed, Abderazek Ben Abdallah, OASIS 3D Router Design Tutorial, Technical Report, Adaptive Systems Laboratory, Division of Computer Engineering, School of Computer Science and Engineering, University of Aizu, July 8, 2014.
- Akram Ben Ahmed, Mitsuhiro Nakamura, Abderazek Ben Abdallah, OASIS 3D Fault Tolerant Router Hardware Physical Design with TSV, Technical Report, Adaptive Systems Laboratory, Division of Computer Engineering, School of Computer Science and Engineering, University of Aizu, May 28, 2015.
Step 3†
- Investigate about the different approaches for fault detection in NoC systems
- Modify the flit format to host the additional code portion for fault detection and correction.
- Make the necessary modification for the remaining modules of the router.
- Evaluate the performance of the scheme (Area, power, latency, ...)
To be continued
References†
- Mitsunari Ishii, Design and Evaluation of Efficient Error Detection Mechanism for OASIS 3D-NoC, Bachelor Thesis, School of Computer Science and Engineering, The University of Aizu, March 2015. slides.pdf, Thesis.pdf, Technical Report.pdf,
- Run this Tutorial on your machine.
OASIS 3D-Router Hardware Physical Design, Technical Report, Adaptive Systems Laboratory, Division of Computer Engineering, School of Computer Science and Engineering, University of Aizu, July 8, 2014.
- Akram Ben Ahmed, Mitsuhiro Nakamura, Abderazek Ben Abdallah, OASIS 3D Fault Tolerant Router Hardware Physical Design with TSV, Technical Report, Adaptive Systems Laboratory, Division of Computer Engineering, School of Computer Science and Engineering, University of Aizu, May 28, 2015.
- Akram Ben Ahmed, Abderazek Ben Abdallah, OASIS 3D Router Design Tutorial, Technical Report, Adaptive Systems Laboratory, Division of Computer Engineering, School of Computer Science and Engineering, University of Aizu, July 8, 2014.
OASIS NoC†
Backup†
Others†
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