A Standard Debug Interface for OpenMP Target Regions
Authors: Andreas Erik Hindborg (Technical University of Denmark), Ignacio Laguna (Lawrence Livermore National Laboratory), Sven Karlsson (Technical University of Denmark), Dong H. Ahn (Lawrence Livermore National Laboratory)
Abstract: As OpenMP covers more on-node parallelism, debugging OpenMP
programs is becoming challenging. Debuggers often debug OpenMP at a
system-thread level, leaving programmers with limited state
information on OpenMP threads. The OpenMP debugging interface, OMPD,
has been proposed as a standard interface to overcome these
limitations. However, the current specification works only for OpenMP
3.1 -- it cannot handle OpenMP 4.0 programs because it does not
consider OpenMP target constructs. In this work, we study how to
extend OMPD to OpenMP 4.0 and propose a set of OMPD extensions. We
identify crucial scalability issues with the way OMPD currently
represents threads and propose a new representation, Construction of
Online Lightweight Thread handle, COLT, as a scalable solution. Our
evaluation shows that our scheme is feasible as far as basic OMPD
support is provided for OpenMP 4 runtime component and can also
significantly reduce the memory and performance overheads of the
debuggers.
Poster: pdf
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