Facilitating Bug Detection for OpenMP Offloading Applications

Abstract

The paper introduces ARBALEST-VEC, a redesigned dynamic analysis tool for detecting data inconsistencies in OpenMP offloading applications, specifically targeting GPU environments. Building upon the shortcomings of its predecessor, ARBALEST, the new tool incorporates several improvements. ARBALEST-VEC is implemented on a more recent version of LLVM, addressing issues such as inaccurate data movement modeling and insufficient debugging information in ARBALEST. It introduces a new OpenMP Tool interface (OMPT) event, device_mem, to accurately capture data movements, thus reducing runtime overhead and enhancing debugging accuracy. The tool also leverages additional debug information available in the LLVM toolchain to generate more detailed and user-friendly bug reports. Furthermore, ARBALEST-VEC employs a dedicated shadow memory and vectorized dynamic analysis using SIMD instructions to improve the performance and precision of data inconsistency detection. Evaluations demonstrate that ARBALEST-VEC offers improved accuracy, usability, and performance over ARBALEST, with lower time overhead and more predictable memory usage, making it more suitable for real-world OpenMP programs.