Thu Mar 24, 10:30-11:30, 4549 BH

Compiler technologies for efficiency and reliability in Embedded Systems

Rajeev Barua
University of Maryland, College Park

My talk will overview our recent work in embedded systems along
two directions.  The first part of the talk will focus on the problem
of out-of-memory errors.  Given the difficulty of estimating the memory
requirement of applications, out-of-memory errors are a serious source
of unreliability in safety-critical embedded systems. In embedded
systems, out-of-memory errors are common, since no swap space
is available; and are not detected, since virtual memory is usually
absent.  We propose a new software-only compiler-based method that
is guaranteed to detect all memory overflows at run-time at very
low run-time and energy overhead (about 1% for each).  By detecting
errors, system-specific remedial action becomes possible. Further,
we show ways by which the crash may be postponed or avoided by
automatically recovering previously un-used memory space.

The second part of the talk will overview our proposed methods
for allocating program data to scratch-pad memory in embedded systems.
A scratch-pad is a fast compiler-managed SRAM memory that replaces
the hardware-managed cache. It is motivated by its better real-time
guarantees versus cache and by its significantly lower overheads in
energy consumption, area and overall runtime, even with a simple
allocation scheme.  Two new scratch-pad allocation methods will be
reviewed.  The first method is the first to be able to
allocate a portion of the stack data in scratch-pad memory.  The
second method improves upon the first by being the first general
method that can move variables between SRAM and DRAM during the
execution of the program.  Large improvements in run-time and
energy consumption are demonstrated for both methods.

Biography:  Dr. Rajeev Barua is an Assistant Professor of Electrical
and Computer Engineering at the University of Maryland.  He received
his Ph.D in Computer Science and Electrical Engineering from the
Massachusetts Institute of Technology in 2000.  He is a recipient of
the NSF CAREER award in 2002, and of the UMD George Corcoran Award
for teaching excellence in 2003. His research interests are in the
areas of embedded systems, compilers and computer architecture.
Homepage URL:  http://www.ece.umd.edu/~barua

Host: Jens Palsberg