Browsing by Author "Li, Jianjun"

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Dynamic Register Promotion of Stack Variables
(2011)
Li, Jianjun
;
Wu, Chenggang
;
Hsu, Wei-Chung
;
資訊工程學系
;
Department of Computer Science
Dynamic Binary Translation (DBT) has been widely used in various applications. Although new architectures and micro-architectures often create performance opportunities for programmers and compilers, such performance opportunities may not be exploited by legacy executables. For example, the additional general-purpose and XMM registers in the Intel64 architecture do not benefit the IA-32 binaries. In this paper, we designed and developed a DBT system to dynamically promote stack variables in the source binaries to the additional registers of the target architecture. One of the most challenging problems is how to deal with the possible but rare memory aliases between promoted stack variables and other implicit memory references. We devised a runtime alias detection approach based on the page protection mechanism in Linux and a novel stack switching method to catch memory aliases at run-time. This approach is much less expensive than traditional approaches like inserting address checking instructions. On an Intel64 platform, our DBT system with speculative stack variable promotion has sped up several SPEC CPU2006 benchmarks in IA-32 code, with the largest performance gain over 45%.
Efficient and Effective Misaligned Data Access Handling in a Dynamic Binary Translation System
(2011-07-01)
Li, Jianjun
;
Wu, Chenggang
;
Hsu, Wei-Chung
;
資訊工程學系
;
Department of Computer Science
Binary Translation (BT) has been commonly used to migrate application software across Instruction Set Architectures (ISAs). Some architectures, such as X86, allow Misaligned Data Accesses (MDAs), while most modern architectures require natural data alignments. In a binary translation system, where the source ISA allows MDA and the target ISA does not, memory operations must be carefully translated. Naive translation may cause frequent misaligned data access traps to occur at runtime on the target machine and severely slow down the migrated application. This article evaluates different approaches in handling MDA in a binary translation system including how to identify MDA candidates and how to translate such memory instructions. This article also proposes some new mechanisms to more effectively deal with MDAs. Extensive measurements based on SPEC CPU2000 and CPU2006 benchmarks show that the proposed approaches are more effective than existing methods and getting close to the performance upper bound of MDA handling.