[Openmp-dev] Build is terribly slow on Arm

[Jonas Hahnfeld via Openmp-dev]

You wrote "They were both Debug build". Maybe I misunderstand?

Am Mittwoch, den 10.06.2020, 18:52 +0900 schrieb Itaru Kitayama:
> Why do you think I build in Debug? I try to
> avoid that all time.
> 
> On Wed, Jun 10, 2020 at 18:38 Jonas Hahnfeld <hahnjo at hahnjo.de> wrote:
> > You should not use Debug build to compare the performance of compilers.
> > As you're targeting different architectures, you might run into
> > different checks in the two backends. I believe it's possible this is
> > triggered by OpenMP code generation which might hit some corner cases.
> > This could also happen in Release builds, but might be less probable.
> > 
> > Also keep in mind that AArch64 (which you're probably talking about in
> > the context of HPC) now uses GlobalISel in some configurations. I don't
> > remember if it's with or without optimizations (or maybe even both
> > nowadays?), but you can try to deactivate this on the command line to
> > rule out this area.
> > 
> > Regards
> > Jonas
> > 
> > Am Dienstag, den 09.06.2020, 08:12 +0900 schrieb Itaru Kitayama via
> > Openmp-dev:
> > > They were both Debug build, but it took 20-25 minutes to finish on Arm.
> > > 
> > > On Tue, Jun 9, 2020 at 7:50 AM Itaru Kitayama <
> > > itaru.kitayama at gmail.com
> > > > wrote:
> > > > My OpenMP offloading app builds within a minute or so on
> > > > x86, but the same app takes longer than 5 minutes on Arm.
> > > > How do I investigate this further, supplying -v and post
> > > > the log here?
> 
> 
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