Multi-Opt - Multi-criterial Code Optimization for Embedded Hard Real-Time Systems

Multi-Opt - 嵌入式硬实时系统的多标准代码优化

• 批准号: 380772147
• 负责人: Professor Dr. Heiko Falk
• 金额: --
• 依托单位: Institut für Eingebettete Systeme E-13
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/380772147?language=en
• 关键词: Multi; Opt; criterial; Code; Optimization

Key requirement of hard real-time systems is to meet timing constraints. However, embedded systems often have additional design constraints that are also not negligible due to technical limitations or financial budget. For example, program and data memories of real architectures are often very tight. Moreover, energy consumption is another important criterion for battery-powered, mobile embedded systems. Therefore, three critical design parameters, namely Worst-Case Execution Time (WCET), code size and energy consumption, have to be considered designing hard real-time systems.A properly designed system must comply with all resource constraints. If one or several design constraints are violated, the hardware platform can be modified in order to meet all resource constraints. Adapting hardware to achieve the necessary functionality of the system together with meeting all resource requirements usually leads to greatly increased costs. Furthermore, side effects of such hardware modifications are difficult to predict. Therefore, a more preferable approach is to optimize an embedded system’s software by a compiler trying to meet all design requirements.During the first funding period, the project focused on exploring compiler-based methods for optimizing WCET, code size and energy consumption. Considering them as optimization goals at compile-time leads to a multi-criterial optimization, since they cannot be perfectly optimized simultaneously. These criteria usually contradict each other, i.e., improving one of them can have a negative effect on others. It has been shown during the first funding period that population-based optimization heuristics are able to provide good results that successfully trade the different contradicting objectives. However, such multi-criterial optimizations are very time and memory consuming due to costly executions of required timing analyses in order to evaluate these objective functions. Instead of performing costly analyses each and every time that an optimization needs objectives' values, predicting the values of objective functions could help to improve the compiler's run-times.For these reasons, the present follow-up proposal aims to develop novel approaches based on a prediction of the objectives' values in order to support population-based optimizations at compile-time. The project will focus on the design of a framework allowing to predict objectives in order to decrease the run-times of multi-criterial optimizations relying on costly analyses. The aim is to design a framework based on mathematical prediction models that allows to optimize embedded software for multiple criteria simultaneously in both an effective and efficient manner.

硬实时系统的关键要求是满足正时限制。但是，嵌入式系统通常具有其他设计约束，由于技术限制或财务预算，这些限制也不可以忽略不计。例如，实际体系结构的程序和数据记忆通常非常紧密。此外，能源消耗是电池供电的移动嵌入式系统的另一个重要标准。因此，必须将三个关键的设计参数，即最差的执行时间（WCET），代码大小和能耗，必须被视为设计硬实时系统的设计。正确设计的系统必须符合所有资源约束。如果违反了一个或几个设计约束，则可以修改硬件平台以满足所有资源约束。调整硬件以实现系统的必要功能以及满足所有资源需求，通常会导致成本增加。此外，这种硬件修改的副作用很难预测。因此，一种更喜欢的方法是通过编译器来优化嵌入式系统的软件，试图满足所有设计要求。在第一个资助期间，该项目着重于探索基于编译器的方法，以优化WCET，代码尺寸和能源消耗。将它们视为编译时的优化目标会导致多标准优化，因为它们不能简单地进行完美优化。这些标准通常相互矛盾，即改善其中一个标准可能对他人产生负面影响。在第一个资助期间，已经显示出基于人群的优化启发式方法能够提供良好的结果，以成功地交易不同的矛盾目标。但是，这种多标准优化是由于代价昂贵所需的计时分析以评估这些目标功能而导致的时间和内存消耗。与其进行昂贵的分析，每当优化需要目标值的值时，预测目标函数的值就可以帮助改善编译器的运行时间。出于这些原因，目前的后续提案旨在基于对目标值的预测来开发新的方法，以支持基于基于人群的优化时间。该项目将着重于设计框架的设计，以预测目标，以减少依靠昂贵分析的多标准优化的运行时间。目的是设计一个基于数学预测模型的框架，该框架允许仅以有效和有效的方式优化多个标准的嵌入式软件。

项目成果

Compiler-Based Code Compression for Hard Real-Time Systems

用于硬实时系统的基于编译器的代码压缩

• DOI: 10.1145/3323439.3323976
• 发表时间: 2019
• 期刊: Proceedings of the 22nd International Workshop on Software and Compilers for Embedded Systems
• 作者: Kateryna Muts;Arno Luppold;Heiko Falk
• 通讯作者: Heiko Falk

Multi-Criteria Compiler-Based Optimization of Hard Real-Time Systems

• DOI: 10.1145/3207719.3207730
• 发表时间: 2018-05
• 期刊: Proceedings of the 21st International Workshop on Software and Compilers for Embedded Systems
• 作者: Kateryna Muts;Arno Luppold;H. Falk

Predicting Objectives on a Reduced Search Space of Multiobjective Function Inlining

• DOI: 10.1145/3493229.3493303
• 发表时间: 2021-11
• 期刊: Proceedings of the 24th International Workshop on Software and Compilers for Embedded Systems
• 作者: Kateryna Muts;H. Falk

Multi-Criteria Function Inlining for Hard Real-Time Systems

• DOI: 10.1145/3394810.3394819
• 发表时间: 2020-06
• 期刊: Proceedings of the 28th International Conference on Real-Time Networks and Systems
• 作者: Kateryna Muts;H. Falk

Compiler-based WCET prediction performing function specialization

• DOI: 10.1145/3378678.3391879
• 发表时间: 2020-05
• 期刊: Proceedings of the 23th International Workshop on Software and Compilers for Embedded Systems
• 作者: Kateryna Muts;H. Falk