Contributions

1
A Cross-Layer, Error-Aware Methodology for
Reliable Design of Resource Constrained Embedded
Systems
Cross-Layer Error-Aware Approaches
PPC (Partially Protected Cache)
CC-PROTECT (Cooperative Cross-layer Protection)

• Soft error rate is increasing exponentially as
  technology scales
• Redundancy-based techniques (e.g., Error
  Correction Codes) are effective but expensive in
  terms of power and performance
• Propose a PPC architecture to provide an unequal
  data protection for maximal reliability with
  minimal overheads

• Cooperative error-aware methods across
  abstraction layers

• Our approach exploits error-tolerance and error
  control schemes across layers
• Our approach coordinates and optimizes mobile
  embedded systems for maximal reliability with
  minimal overheads of power and performance

Mobile Video Application

• PPC Unequal protection at hardware exploiting
  error-tolerance at application
• CC-PROTECT Middleware-driven cooperative
  exploitation of errors and error control schemes
  across layers

CC-PROTECT
Intentional or Soft-Error Induced Frame Drop
Error-Aware Video Encoder (EAVE)
Error- Aware Video
Original Video
Error-Resilient Encoder (e.g., PBPAIR)
Error-Controller (e.g., frame dropping)
Error- Injected Video

• Not all data is equally failure critical

(2) Vulnerable time closely estimates failure rate
Error Injection Rate Frame Loss Rate
Drop Forward Recovery (DFR)
PPC
Feedback

• Failure non-critical data (e.g., multimedia data)
• Failure critical data (e.g., program variables)

• Pages causing high vulnerable time are failure
  critical data

Monitor Translate SER
Trigger Selective DFR
Support EAVE PPC
Parameter
frame K
frame K1
Middleware/OS
invulnerable
Incoming
Eviction
Read
Write
data
Error detection
Unprotected Cache
Protected Cache
EDC

• Compiler and OS help to partition data into a PPC

(Error Detection Codes)
t0
t1
t2
t3
PPC
Vulnerable
Publications
Contributions
Future Directions
1 K. Lee, M. Kim, N. Dutt, and N.
Venkatasubramanian. Error exploiting video
encoder to extend energy/qos tradeoffs for mobile
embedded systems. In 6th IFIP Working Conference
on Distributed and Parallel Embedded Systems
(DIPES), Sep. 2008 2 K. Lee, A. Shrivastava, N.
Dutt, and N. Venkatasubramanian. Data
partitioning techniques for partially protected
caches to reduce soft error induced failures. In
6th IFIP Working Conference on Distributed and
Parallel Embedded Systems (DIPES), Sep. 2008 3
K. Lee, A. Shrivastava, I. Issenin, N. Dutt, and
N. Venkatasubramanian. Mitigating soft error
failures for multimedia applications by selective
data protection. In Int. Conference on
Compilers, Architecture, Synthesis for Embedded
Systems (CASES), Oct. 2006. 4 S. Mohapatra, R.
Cornea, H. Oh, K. Lee, M. Kim, N. Dutt, R. Gupta,
A. Nicolau, S. Shukla, and N. Venkatasubramanian.
A cross-layer approach for power-performance
optimization in distributed mobile systems. In
Next Generation Software Program in conjunction
with IEEE International Parallel and Distributed
Processing Symposium (IPDPS), April 2005. 5 K.
Lee, A. Shrivastava, M. Kim, N. Dutt, and N.
Venkatasubramanian. Cross-layer interactions of
error control schemes for mobile multimedia
systems. In Technical Report, University of
California at Irvine, Apr. 2008.

• Improve energy consumption and performance
  without losing reliability at the cost of QoS
• Open opportunity to explore the expanded design
  space by exploiting error-awareness
  (error-tolerance and error-resilience) across
  system layers

• Combine approaches across layers for further
  improvements
• Develop middleware approaches to coordinate
  multiple system parameters across layers in
  distributed embedded systems

• Cooperate approaches to maximize the reliability
  with minimal loss in terms of power, performance,
  and QoS

Kyoungwoo Lee (kyoungwl_at_ics.uci.edu) Donald Bren
School of Information and Computer Sciences,
University of California at Irvine, CA 92697,
USA Co-advisors Nikil Dutt and Nalini
Venkatasubramanian