[Openmp-dev] Offloading application build with a Trunk Debug Clang is so slow

[Itaru Kitayama via Openmp-dev]

Hi all,
>From discussions I had in the llvm-dev mailing list, I realized thjat I
really should not have used a Debug Clang at all for my
app build. Although at this moment, trunk is broken for my application of
interest, I can go back to mid October of trunk and
I can build my app with the Clang which is a Release build, but also
configured to print informative messages from libomptarget.


On Mon, Dec 23, 2019 at 12:47 PM Itaru Kitayama <itaru.kitayama at gmail.com>
wrote:

> I've collected Clang build performance data with the -ftime-trace like
> below
>
> clang++ -ftime-trace -g -fopenmp -fopenmp-targets=nvptx64 mini.cpp
>
> . I'm uploading corresponding .json files for your review as to why the
> latest Clang is slow.
>
> On Sun, Dec 22, 2019 at 10:23 AM Alexey Bataev <a.bataev at hotmail.com>
> wrote:
>
>> Check-libomptarget and check-libomptarget-nvptx  do.
>>
>> Best regards,
>> Alexey Bataev
>>
>> 21 дек. 2019 г., в 20:13, Itaru Kitayama via Openmp-dev <
>> openmp-dev at lists.llvm.org> написал(а):
>>
>> 
>> On x86 I see the same significant slowdown when building an app with
>> Debug Clang.
>>
>> Does make check-openmp exercise any part of the offloading features?
>>
>> On Fri, Dec 20, 2019 at 8:35 AM Doerfert, Johannes <jdoerfert at anl.gov>
>> wrote:
>>
>>> On 12/19, Itaru Kitayama wrote:
>>> > On POWER8, my app builds 40 minutes with the Debug Clang (40 times
>>> increase
>>> > of time, when
>>> > it is built with Release Clang), but on an x86 host, it just takes
>>> about 10
>>> > minutes and it is bearable.
>>> >
>>> > Could this be PowerPC specific, is it why most people aren't aware of
>>> the
>>> > slowness?
>>>
>>> That could most certainly be. Alexey should build on Power regularly
>>> though.
>>>
>>>
>>> _______________________________________________
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>> Openmp-dev at lists.llvm.org
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>>
>>
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