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

[Itaru Kitayama via Openmp-dev]

Alexey, I was saying that Initializing offloading rum time at runtime was
failing with NEST.

On Tue, Jan 7, 2020 at 1:47 Alexey Bataev <a.bataev at outlook.com> wrote:

> Hi Itaru, I tried to build the NEST with offloading support. It is built
> successfully. How can I see that it does not work?
>
> -------------
> Best regards,
> Alexey Bataev
>
> 05.01.2020 8:53 PM, Itaru Kitayama пишет:
>
> 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.
>>>>
>>>>
>>>> _______________________________________________
>>> Openmp-dev mailing list
>>> Openmp-dev at lists.llvm.org
>>> https://lists.llvm.org/cgi-bin/mailman/listinfo/openmp-dev
>>>
>>>
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