Implementation Issues of Loop-Level Speculative Run-Time Parallelization [chapter]

Devang Patel, Lawrence Rauchwerger
1999 Lecture Notes in Computer Science  
Current parallelizing compilers cannot identify a significant fraction of parallelizable loops because they have complex or statically insufficiently defined access patterns. We advocate a novel framework for the identification of parallel loops. It speculatively executes a loop as a doall and applies a fully parallel data dependence test to check for any unsatisfied data dependencies; if the test fails, then the loop is re-executed serially. We will present the principles of the design and
more » ... ementation of a compiler that employs both run-time and static techniques to parallelize dynamic applications. Run-time optimizations always represent a tradeoff between a speculated potential benefit and a certain (sure) overhead that must be paid. We will introduce techniques that take advantage of classic compiler methods to reduce the cost of run-time optimization thus tilting the outcome of speculation in favor of significant performance gains. Experimental results from the PERFECT, SPEC and NCSA Benchmark suites show that these techniques yield speedups not obtainable by any other known method.
doi:10.1007/978-3-540-49051-7_13 fatcat:x3wlmc6nbrb3dogno7e4ri6cri