UnifiedMemoryStreams example get stuck

Greetings, I am running the ./UnifiedMemoryStreams example given by CUDA 7.0 and receive the following message

GPU Device 0: “GeForce GTX 980” with compute capability 5.2

and later nothing … e.g. it get stuck.

I have writen a small test:

...

int *ret;
cudaStream_t stream = NULL;
	
cudaStreamCreate(&stream);
	
if(!stream) {
	
	printf("failed to alloc a stream\n");
		return 0;
	
}

	
checkCuda(cudaMallocManaged(&ret, 1000000 * sizeof(int), cudaMemAttachHost))
	
checkCuda(cudaStreamCreate(&stream));

memset((void *)ret, 0xAA, 1000000 * sizeof(int));

printf("after ret setting we have ret[1] == %d\n", ret[1]);

...

And can see that memset get stuck.

The execution environment is a new system 76 running Ubuntu 15.04, and GeForce GTX 980.

P.S. the same test on a different machine (a mac book pro (dual boot)) running Ubuntu 14.04 with CUDA 7.0 and GeForce GT 750M runs this test without any issues.

Please help :-)

Thank you.

Ubuntu 15.04 is not an officially supported distro for CUDA 7.

You might want to switch to Ubuntu 14.04

Tx. I suspect that this is the issue…

This thread may be of interest:

https://devtalk.nvidia.com/default/topic/804316/cuda-programming-and-performance/is-unified-memory-broken-for-anyone-else-o_o/