Hi Chung-Lin!
On Tue, 25 Sep 2018 21:11:58 +0800, Chung-Lin Tang <chunglin_t...@mentor.com>
wrote:
> Hi Tom,
> this patch removes large portions of plugin/plugin-nvptx.c, since a lot of it
> is
> now in oacc-async.c now. The new code is essentially a NVPTX/CUDA-specific
> implementation
> of the new-style goacc_asyncqueues.
> --- a/libgomp/plugin/plugin-nvptx.c
> +++ b/libgomp/plugin/plugin-nvptx.c
> +struct goacc_asyncqueue *
> +GOMP_OFFLOAD_openacc_async_construct (void)
> +{
> + struct goacc_asyncqueue *aq
> + = GOMP_PLUGIN_malloc (sizeof (struct goacc_asyncqueue));
> + aq->cuda_stream = NULL;
> + CUDA_CALL_ASSERT (cuStreamCreate, &aq->cuda_stream, CU_STREAM_DEFAULT);
Curiously (this was the same in the code before): does this have to be
"CU_STREAM_DEFAULT" instead of "CU_STREAM_NON_BLOCKING", because we want
to block anything from running in parallel with "acc_async_sync" GPU
kernels, that use the "NULL" stream? (Not asking you to change this now,
but I wonder if this is overly strict?)
> + if (aq->cuda_stream == NULL)
> + GOMP_PLUGIN_fatal ("CUDA stream create NULL\n");
Can this actually happen, given the "CUDA_CALL_ASSERT" usage above?
> + CUDA_CALL_ASSERT (cuStreamSynchronize, aq->cuda_stream);
Why is the synchronization needed here?
> + return aq;
> +}
Grüße
Thomas
