[mvapich-discuss] MVAPICH 2-GDR Issue with MPI_Allreduce

[Herten, Andreas]

Dear MV2 Support,

We see an issue when calling MPI_Allreduce on GPU memory buffers. The reduction produces wrong results or the program even seg faults.
I wrote up a more detailed description including a minimal reproducing example and some of our experiments here:
	https://urldefense.com/v3/__https://gist.github.com/AndiH/b929b50b4c8d25137e0bfee25db63791__;!!KGKeukY!mzGbEBbFzC6husDgfEvXunnb3UPLwL594G78RXrsJVo4LO7VTQv4egSuOcAN5Ckv8tRa5OTWYyKLHsI$ 

Is this a bug?

New year’s greetings,

-Andreas
—
NVIDIA Application Lab
Jülich Supercomputing Centre
Forschungszentrum Jülich, Germany
+49 2461 61 1825

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