Low-cost error detection through high-level synthesis

System-on-chip design is becoming increasingly complex as technology scaling enables more and more functionality on a chip. This scaling and complexity has resulted in a variety of reliability and validation challenges including logic bugs, hot spots, wear-out, and soft errors. To make matters worse, as we reach the limits of Dennard scaling, efforts to improve system performance and energy efficiency have resulted in the integration of a wide variety of complex hardware accelerators in SoCs. Thus the challenge is to design complex, custom hardware that is efficient, but also correct and reliable. High-level synthesis shows promise to address the problem of complex hardware design by providing a bridge from the high-productivity software domain to the hardware design process. Much research has been done on high-level synthesis efficiency optimizations. This thesis shows that high-level synthesis also has the power to address validation and reliability challenges through two solutions. One solution for circuit reliability is modulo-3 shadow datapaths: performing lightweight shadow computations in modulo-3 space for each main computation. We leverage the binding and scheduling flexibility of high-level synthesis to detect control errors through diverse binding and minimize area cost through intelligent checkpoint scheduling and modulo-3 reducer sharing. We introduce logic and dataflow optimizations to further reduce cost. We evaluated our technique with 12 high-level synthesis benchmarks from the arithmetic-oriented PolyBench benchmark suite using FPGA emulated netlist-level error injection. We observe coverages of 99.1% for stuck-at faults, 99.5% for soft errors, and 99.6% for timing errors with a 25.7% area cost and negligible performance impact. Leveraging a mean error detection latency of 12.75 cycles (4150x faster than end result check) for soft errors, we also explore a rollback recovery method with an additional area cost of 28.0%, observing a 175x increase in reliability against soft errors. Another solution for rapid post-silicon validation of accelerator designs is Hybrid Quick Error Detection (H-QED): inserting signature generation logic in a hardware design to create a heavily compressed signature stream that captures the internal behavior of the design at a fine temporal and spatial granularity for comparison with a reference set of signatures generated by high-level simulation to detect bugs. Using H-QED, we demonstrate an improvement in error detection latency (time elapsed from when a bug is activated to when it manifests as an observable failure) of two orders of magnitude and a threefold improvement in bug coverage compared to traditional post-silicon validation techniques. H-QED also uncovered previously unknown bugs in the CHStone benchmark suite, which is widely used by the HLS community. H-QED incurs less than 10% area overhead for the accelerator it validates with negligible performance impact, and we also introduce techniques to minimize any possible intrusiveness introduced by H-QED.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Electrical & Computer Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2016

Author dc:creator

• Campbell, Keith A

Contributors dc:contributor

• Chen, Deming

• low cost
• high performance
• High-level synthesis
• Automation
• error detection
• scheduling
• binding
• compiler transformation
• compiler optimization
• pipelining
• modulo arithmetic
• logic optimization
• state machine
• datapath, control logic
• shadow logic
• electrical bugs
• Aliasing
• stuck-at faults
• soft errors
• timing errors
• checkpointing
• rollback
• recovery
• post-silicon validation
• Accelerators
• system on a chip
• signature generation
• execution signatures
• execution hashing
• logic bugs
• nondeterministic bugs
• masked errors
• circuit reliability
• hot spots
• wear out
• silent data corruption
• observability
• detection latency
• mixed datapath
• diversity
• checkpoint corruption
• error injection
• error removal
• Quick Error Detection (QED)
• Hybrid Quick Error Detection (H-QED)
• hybrid hardware/software
• execution tracing
• address conversion
• undefined behavior
• High-Level Synthesis (HLS) engine bugs
• detection coverage

Statement dc:rights

• Copyright 2015 Keith A. Campbell

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/89068

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/89068