[cfe-dev] openmp 4.5 and cuda streams

[GMail via cfe-dev]

I don't think it will be very easy. It requires some additional work in
libomptarget + some fixes in the clang itself. Otherwise there might be
some race conditions.

-------------
Best regards,
Alexey Bataev

30.10.2019 2:40 PM, Finkel, Hal J. via cfe-dev пишет:
> [+Ye, Johannes]
>
> I recall that we've also observed this behavior. Ye, Johannes, we had a 
> work-around and a patch, correct?
>
>   -Hal
>
> On 10/30/19 12:28 PM, Alessandro Gabbana via cfe-dev wrote:
>> Dear All,
>>
>> I'm using clang 9.0.0 to compile a code which offloads sections of a 
>> code on a GPU using the openmp target construct.
>> I also use the nowait clause to overlap the execution of certain 
>> kernels and/or host<->device memory transfers.
>> However, using the nvidia profiler I've noticed that when I compile 
>> the code with clang only one cuda stream is active,
>> and therefore the execution gets serialized. On the other hand, when 
>> compiling with XLC I see that kernels are executed
>> on different streams. I could not understand if this is the expected 
>> behavior (e.g. the nowait clause is currently not supported),
>> or if I'm missing something. I'm using a NVIDIA Tesla P100 GPU and 
>> compiling with the following options:
>>
>> -target x86_64-pc-linux-gnu -fopenmp 
>> -fopenmp-targets=nvptx64-nvidia-cuda 
>> -Xopenmp-target=nvptx64-nvidia-cuda -march=sm_60
>>
>> best wishes
>>
>> Alessandro
>>
>> _______________________________________________
>> cfe-dev mailing list
>> cfe-dev at lists.llvm.org
>> https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
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