[Openmp-commits] [PATCH] D77609: [OpenMP] Added the support for hidden helper task in RTL

Joachim Protze via Phabricator via Openmp-commits openmp-commits at lists.llvm.org
Wed Mar 17 09:07:24 PDT 2021

protze.joachim added a comment.

In D77609#2631784 <https://reviews.llvm.org/D77609#2631784>, @ronlieb wrote:

> i tried using 
> export LIBOMP_USE_HIDDEN_HELPER_TASK=0 and rebuilding/rerunning spec cpu2017 fpspeed base.
> and still see the performance issues in 619.lbm and all the other fpspeed benchmarks.
> The GeoMean dropped aprox 30%

Wasn't spec cpu meant to measure single-core performance? I can see how -fopenmp or -fopenmp-simd might help to turn on vectorization. But none of these flags should turn on OpenMP directives present in the code and make the code multi-threaded (in spec cpu 2006 there were actually `#if !defined(SPEC_CPU)` arround all OpenMP directives and includes). Are the resulting binaries really linked against libomp? Without any OpenMP symbols in the application, the linker should just drop libomp.

  rG LLVM Github Monorepo



More information about the Openmp-commits mailing list