[Starpu-devel] STARPU_ENABLE_CUDA_GPU_GPU_DIRECT doesn't work

[Hush Zhou <hush.zhou@gmail.com>]

Hi,
I'm trying to run the cholesky_implicit example with

STARPU_NCPU=2 STARPU_NCUDA=2 STARPU_ENABLE_CUDA_GPU_GPU_DIRECT=1
./cholesky_implicit

My machine is configured with:

Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz
GeForce GT 620
GeForce GTX 660

And the starpu was configured with:
--enable-verbose --enable-stats --enable-perf-debug --enabl
e-model-debug --enable-memory-stats --enable-sc-hypervisor

the STARPU_ENABLE_CUDA_GPU_GPU_DIRECT was enabled by default.


But the data transfer stats shows as following:

#---------------------
Data transfer stats:
TOTAL transfers 221.000000 MB
    1 <-> 0 98.250000 MB
        1 -> 0  46.000000 MB
        0 -> 1  52.250000 MB
    2 <-> 0 12.250000 MB
        2 -> 0  3.750000 MB
        0 -> 2  8.500000 MB
#---------------------

It seems that data didn't transfer directly from GPU to GPU. Is it
normal? How could I solve this problem?



Best,
Husheng