test_cuda.py 文件源码

def test_caching_pinned_memory_multi_gpu(self):
        # checks that the events preventing pinned memory from being re-used
        # too early are recorded on the correct GPU
        cycles_per_ms = get_cycles_per_ms()

        t = torch.FloatTensor([1]).pin_memory()
        ptr = t.data_ptr()
        gpu_tensor0 = torch.cuda.FloatTensor([0], device=0)
        gpu_tensor1 = torch.cuda.FloatTensor([0], device=1)

        with torch.cuda.device(1):
            torch.cuda._sleep(int(50 * cycles_per_ms))  # delay the copy
            gpu_tensor1.copy_(t, async=True)

        del t
        t = torch.FloatTensor([2]).pin_memory()
        self.assertNotEqual(t.data_ptr(), ptr, 'allocation re-used too soon')

        with torch.cuda.device(0):
            gpu_tensor0.copy_(t, async=True)

        self.assertEqual(gpu_tensor1[0], 1)
        self.assertEqual(gpu_tensor0[0], 2)