Providing time- and space- efficient procedure calls for asynchronous software thread integration

  • Authors:

  • Vasanth Asokan;Alexander G. Dean

  • Affiliations:

  • North Carolina State University, Raleigh, NC;North Carolina State University, Raleigh, NC

  • Venue:
  • Proceedings of the 2004 international conference on Compilers, architecture, and synthesis for embedded systems
  • Year:
  • 2004

Quantified Score

Hi-index 0.00

Visualization

Abstract

Asynchronous Software Thread Integration (ASTI) provides fine-grain concurrency in real-time threads by statically scheduling (integrating) code from primary threads into secondary threads, reducing the context switching needed and allowing recovery of fine-grain idle time. Unlike STI, ASTI allows asynchronous thread progress.Current ASTI techniques do not support procedure calls in the secondary thread because they lead to timing conflicts during static scheduling. ASTI requires knowing the secondary thread's instruction execution schedule to guide placement of real-time instructions from the primary thread. A secondary thread procedure called from multiple sites will have ambiguous timing at compile time.In this paper we remove this constraint using both procedure inlining and cloning. We present a formal approach to choosing a subset of calls to inline and to remove the timing conflicts in the remaining call sites in an efficient fashion. Excessive inlining and cloning both lead to code size explosion, while poor choices in timing conflict elimination slow program execution. The cloned threads show a significant speedup when compared to non-cloned versions yet have low code expansion. The techniques presented here have been implemented in our post-pass compiler Thrint and demonstrated on a benchmark suite of secondary threads representative of low-end embedded systems.