A Multilevel Introspective Dynamic Optimization System For Holistic Power-Aware Computing

Power consumption is rapidly becoming the dominant limiting factor for further improvements in computer design. Curiously, this applies both at the "high end" of workstations and servers and the "low end" of handheld devices and embedded computers. At the high-end, the challenge lies in dealing with exponentially growing power densities. At the low-end, there is a demand to make mobile devices more powerful and longer lasting, but battery technology is not improving at the same rate that power consumption is rising. Traditional power-management research is fragmented; techniques are being developed at specific levels, without fully exploring their synergy with other levels. Most software techniques target either operating systems or compilers but do not explore the interaction between the two layers. These techniques also have not fully explored the potential of virtual machines for power management. In contrast, we are developing a system that integrates information from multiple levels of software and hardware, connecting these levels through a communication channel. At the heart of this system are a virtual machine that compiles and dynamically profiles code, and an optimizer that reoptimizes all code, including that of applications and the virtual machine itself. We believe this introspective, holistic approach enables more informed power-management decisions

Eine Methode der effizienten und verifizierbaren Programmannotation für den Transport von Escape-Informationen

JIT compilation is frequently employed in order to speedup the execution of platform-independent and dynamically extensible mobile code applications. Since the time required for dynamic compilation directly influences a program's execution time, JIT compilers usually utilize only simple and fast techniques for program analysis and optimization. Program annotations can be used to improve the analysis and optimizitation process of a JIT compiler. Program annotations allow a mobile code system derive information about a program, on the producer side, and transmit that information along with the program to the consumer side. In this work, we present an inherently safe annotation technique for the safe transmission of escape information. The annotation technique described in this work is built on the SafeTSA mobile code format and is implemented as a simple extension of SafeTSA's type system. The space required for these annotations is minimal, and measurements of compilation time show that using information from an offline escape analysis in form of program annotations is evident faster than performing the escape analysis at runtime