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8th International Workshop on
Software and Compilers for Embedded Systems
SCOPES 2004
Workshop Program - Presentation Abstract
| A Flexible Tradeoff between Code Size and WCET Using a Dual
Instruction Set Processor |
Sheayun Lee - Seoul National University
Jaejin Lee - Seoul National University
Chang Yun Park - Chungang University
Sang Lyul Min - Seoul National University
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| Embedded systems are often constrained in terms of both code size
and execution time, due to a limited amount of available memory and
real-time nature of applications. A dual instruction set processor,
which supports a reduced instruction set (16 bits/instruction) in
addition to a full instruction set (32 bits/instruction), allows an
opportunity for a tradeoff between these two performance criteria.
Specifically, while the reduced instruction set can be used to reduce
code size by providing smaller instructions, a program compiled into the
reduced instruction set typically runs slower than the same program
compiled into the full instruction set. Motivated by this observation,
we propose a code generation technique that exploits this tradeoff
relationship by selectively using the two instruction sets for different
sections in the program. The proposed technique not only provides a
mechanism to enable a flexible tradeoff between a program's code size
and its execution time, but also optimizes the program towards enhancing
its WCET (worst case execution time). The results from our experiments
show that our proposed technique can be effectively used to fine-tune an
application program on a spectrum of code size and worst case
performance, which in turn enables a system-wide optimization on memory
space and execution speed involving multiple applications. |
Presentation
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