[Openmp-dev] Enabling OMPT by default
Joachim Protze via Openmp-dev
openmp-dev at lists.llvm.org
Mon Dec 18 03:58:12 PST 2017
Dear all,
OpenMP 5.0 will introduce OMPT, the OpenMP tools interface. The current
implementation in the LLVM/OpenMP runtime is at the level of OpenMP TR6,
as published in November (with some known issues, were we have patches
under review).
Currently, this feature is deactivated by default (LIBOMP_OMPT_SUPPORT).
According to overhead measurements performed by Intel and on some of our
machines, this feature introduces a worst case runtime overhead of ~4%,
but for most cases basically no overhead.
As I understood, some of the build-bots run the tests when the feature
is enabled. We locally test the changes continuously with different
compiler versions (icc/gcc/clang), but only on x86_64 architecture.
Further, this feature was tested on ppc64.
How should we proceed to enable this feature by default, and get it
tested on other architectures?
For the 6.0 release, I would like to enable OMPT at least for the
supported platforms x86/x86_64 and ppc64.
We would also appreciate collaboration with vendors/users of other
platforms, to ensure the code is running there.
Typically, only the architecture specific offset needs to be added:
https://github.com/llvm-mirror/openmp/blob/master/runtime/test/ompt/callback.h#L95
Looking forward to your feedback,
Joachim
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