Results

**1 - 4**of**4**### A compiler framework for the reduction of worst-case execution times

- Real-Time Systems
, 2010

"... times ..."

(Show Context)
### 11th International Workshop on Software & Compilers for Embedded Systems (SCOPES) 2008 WCET-Driven, Code-Size Critical Procedure Cloning ∗†

"... In the domain of the worst-case execution time (WCET) analysis, loops are an inherent source of unpredictability and loss of precision since the determination of tight and safe information on the number of loop iterations is a difficult task. In particular, data-dependent loops whose iteration count ..."

Abstract
- Add to MetaCart

(Show Context)
In the domain of the worst-case execution time (WCET) analysis, loops are an inherent source of unpredictability and loss of precision since the determination of tight and safe information on the number of loop iterations is a difficult task. In particular, data-dependent loops whose iteration counts depend on function parameters can not be precisely handled by a timing analysis. Procedure Cloning can be exploited to make these loops explicit within the source code allowing a highly precise WCET analysis. In this paper we extend the standard Procedure Cloning optimization by WCET-aware concepts with the objective to improve the tightness of the WCET estimation. Our novel approach is driven by WCET information which successively eliminates code structures leading to overestimated timing results, thus making the code more suitable for the analysis. In addition, the code size increase during the optimization is monitored and large increases are avoided. The effectiveness of our optimization is shown by tests on real-world benchmarks. After performing our optimization, the estimated WCET is reduced by up to 64.2 % while the employed code transformations yield an additional code size increase of 22.6 % on average. In contrast, the averagecase performance being the original objective of Procedure Cloning showed a slight decrease. 1.

### Multi-Criteria Optimization of Hard Real-Time Systems

"... Modern embedded hard real-time systems often have to com-ply with several design constraints. On the one hand, the system’s execution time has to be provably less than or equal to a given deadline. On the other hand, further constraints may be given with regard to maximum code size and en-ergy consu ..."

Abstract
- Add to MetaCart

(Show Context)
Modern embedded hard real-time systems often have to com-ply with several design constraints. On the one hand, the system’s execution time has to be provably less than or equal to a given deadline. On the other hand, further constraints may be given with regard to maximum code size and en-ergy consumption due to limited resources. We propose an idea for a compiler-based approach to automatically opti-mize embedded hard real-time systems with regard to mul-tiple optimization criteria. 1.

### Computing Worst Case Execution Time by Symbolically Executing a Time-accurate Hardware Model

"... Abstract—To ensure that a program will respect all its timing constraints we must be able to compute a safe estimation of its worst case execution time (WCET). However with the increasing sophistication of the processors, computing a precise estimation of the WCET becomes very difficult. In this pap ..."

Abstract
- Add to MetaCart

(Show Context)
Abstract—To ensure that a program will respect all its timing constraints we must be able to compute a safe estimation of its worst case execution time (WCET). However with the increasing sophistication of the processors, computing a precise estimation of the WCET becomes very difficult. In this paper, we propose a novel formal method to compute a precise estimation of the WCET that can be easily parameterized by the hardware architecture. Assuming that there exists an executable timed model of the hardware, we first use symbolic execution to precisely infer the execution time for a given instruction flow. Then we merge the states relying on the loss of precision we are ready to accept. Index Terms—Static analysis, WCET, processor modelization, symbolic execution.