Device agnostic testing

src/diffusers/utils/testing_utils.py

@@ -17,7 +17,7 @@
 from distutils.util import strtobool
 from io import BytesIO, StringIO
 from pathlib import Path
-from typing import List, Optional, Union
+from typing import Callable, Dict, List, Optional, Union
 
 import numpy as np
 import PIL.Image
@@ -58,6 +58,17 @@
 if is_torch_available():
     import torch
 
+    # Set a backend environment variable for any extra module import required for a custom accelerator
+    if "DIFFUSERS_TEST_BACKEND" in os.environ:
+        backend = os.environ["DIFFUSERS_TEST_BACKEND"]
+        try:
+            _ = importlib.import_module(backend)
+        except ModuleNotFoundError as e:
+            raise ModuleNotFoundError(
+                f"Failed to import `DIFFUSERS_TEST_BACKEND` '{backend}'! This should be the name of an installed module \
+                    to enable a specified backend.):\n{e}"
+            ) from e
+
     if "DIFFUSERS_TEST_DEVICE" in os.environ:
         torch_device = os.environ["DIFFUSERS_TEST_DEVICE"]
         try:
@@ -210,6 +221,36 @@ def require_torch_gpu(test_case):
     )
 
 
+# These decorators are for accelerator-specific behaviours that are not GPU-specific
+def require_torch_accelerator(test_case):
+    """Decorator marking a test that requires an accelerator backend and PyTorch."""
+    return unittest.skipUnless(is_torch_available() and torch_device != "cpu", "test requires accelerator+PyTorch")(
+        test_case
+    )
+
+
+def require_torch_accelerator_with_fp16(test_case):
+    """Decorator marking a test that requires an accelerator with support for the FP16 data type."""
+    return unittest.skipUnless(_is_torch_fp16_available(torch_device), "test requires accelerator with fp16 support")(
+        test_case
+    )
+
+
+def require_torch_accelerator_with_fp64(test_case):
+    """Decorator marking a test that requires an accelerator with support for the FP64 data type."""
+    return unittest.skipUnless(_is_torch_fp64_available(torch_device), "test requires accelerator with fp64 support")(
+        test_case
+    )
+
+
+def require_torch_accelerator_with_training(test_case):
+    """Decorator marking a test that requires an accelerator with support for training."""
+    return unittest.skipUnless(
+        is_torch_available() and backend_supports_training(torch_device),
+        "test requires accelerator with training support",
+    )(test_case)
+
+
 def skip_mps(test_case):
     """Decorator marking a test to skip if torch_device is 'mps'"""
     return unittest.skipUnless(torch_device != "mps", "test requires non 'mps' device")(test_case)
@@ -766,3 +807,139 @@ def disable_full_determinism():
     os.environ["CUDA_LAUNCH_BLOCKING"] = "0"
     os.environ["CUBLAS_WORKSPACE_CONFIG"] = ""
     torch.use_deterministic_algorithms(False)
+
+
+# Utils for custom and alternative accelerator devices
+def _is_torch_fp16_available(device):
+    if not is_torch_available():
+        return False
+
+    import torch
+
+    device = torch.device(device)
+
+    try:
+        x = torch.zeros((2, 2), dtype=torch.float16).to(device)
+        _ = x @ x
+    except Exception as e:
+        if device.type == "cuda":
+            raise ValueError(
+                f"You have passed a device of type 'cuda' which should work with 'fp16', but 'cuda' does not seem to be correctly installed on your machine: {e}"
+            )
+
+        return False
+
+
+def _is_torch_fp64_available(device):
+    if not is_torch_available():
+        return False
+
+    import torch
+
+    try:
+        x = torch.zeros((2, 2), dtype=torch.float64).to(device)
+        _ = x @ x
+    except Exception as e:
+        if device.type == "cuda":
+            raise ValueError(
+                f"You have passed a device of type 'cuda' which should work with 'fp64', but 'cuda' does not seem to be correctly installed on your machine: {e}"
+            )
+
+        return False
+
+
+# Guard these lookups for when Torch is not used - alternative accelerator support is for PyTorch
+if is_torch_available():
+    # Behaviour flags
+    BACKEND_SUPPORTS_TRAINING = {"cuda": True, "cpu": True, "mps": False, "default": True}
+
+    # Function definitions
+    BACKEND_EMPTY_CACHE = {"cuda": torch.cuda.empty_cache, "cpu": None, "mps": None, "default": None}
+    BACKEND_DEVICE_COUNT = {"cuda": torch.cuda.device_count, "cpu": lambda: 0, "mps": lambda: 0, "default": 0}
+    BACKEND_MANUAL_SEED = {"cuda": torch.cuda.manual_seed, "cpu": torch.manual_seed, "default": torch.manual_seed}
+
+
+# This dispatches a defined function according to the accelerator from the function definitions.
+def _device_agnostic_dispatch(device: str, dispatch_table: Dict[str, Callable], *args, **kwargs):
+    if device not in dispatch_table:
+        return dispatch_table["default"](*args, **kwargs)
+
+    fn = dispatch_table[device]
+
+    # Some device agnostic functions return values. Need to guard against 'None' instead at
+    # user level
+    if fn is None:
+        return None
+
+    return fn(*args, **kwargs)
+
+
+# These are callables which automatically dispatch the function specific to the accelerator
+def backend_manual_seed(device: str, seed: int):
+    return _device_agnostic_dispatch(device, BACKEND_MANUAL_SEED, seed)
+
+
+def backend_empty_cache(device: str):
+    return _device_agnostic_dispatch(device, BACKEND_EMPTY_CACHE)
+
+
+def backend_device_count(device: str):
+    return _device_agnostic_dispatch(device, BACKEND_DEVICE_COUNT)
+
+
+# These are callables which return boolean behaviour flags and can be used to specify some
+# device agnostic alternative where the feature is unsupported.
+def backend_supports_training(device: str):
+    if not is_torch_available():
+        return False
+
+    if device not in BACKEND_SUPPORTS_TRAINING:
+        device = "default"
+
+    return BACKEND_SUPPORTS_TRAINING[device]
+
+
+# Guard for when Torch is not available
+if is_torch_available():
+    # Update device function dict mapping
+    def update_mapping_from_spec(device_fn_dict: Dict[str, Callable], attribute_name: str):
+        try:
+            # Try to import the function directly
+            spec_fn = getattr(device_spec_module, attribute_name)
+            device_fn_dict[torch_device] = spec_fn
+        except AttributeError as e:
+            # If the function doesn't exist, and there is no default, throw an error
+            if "default" not in device_fn_dict:
+                raise AttributeError(
+                    f"`{attribute_name}` not found in '{device_spec_path}' and no default fallback function found."
+                ) from e
+
+    if "DIFFUSERS_TEST_DEVICE_SPEC" in os.environ:
+        device_spec_path = os.environ["DIFFUSERS_TEST_DEVICE_SPEC"]
+        if not Path(device_spec_path).is_file():
+            raise ValueError(f"Specified path to device specification file is not found. Received {device_spec_path}")
+
+        try:
+            import_name = device_spec_path[: device_spec_path.index(".py")]
+        except ValueError as e:
+            raise ValueError(f"Provided device spec file is not a Python file! Received {device_spec_path}") from e
+
+        device_spec_module = importlib.import_module(import_name)
+
+        try:
+            device_name = device_spec_module.DEVICE_NAME
+        except AttributeError:
+            raise AttributeError("Device spec file did not contain `DEVICE_NAME`")
+
+        if "DIFFUSERS_TEST_DEVICE" in os.environ and torch_device != device_name:
+            msg = f"Mismatch between environment variable `DIFFUSERS_TEST_DEVICE` '{torch_device}' and device found in spec '{device_name}'\n"
+            msg += "Either unset `DIFFUSERS_TEST_DEVICE` or ensure it matches device spec name."
+            raise ValueError(msg)
+
+        torch_device = device_name
+
+        # Add one entry here for each `BACKEND_*` dictionary.
+        update_mapping_from_spec(BACKEND_MANUAL_SEED, "MANUAL_SEED_FN")
+        update_mapping_from_spec(BACKEND_EMPTY_CACHE, "EMPTY_CACHE_FN")
+        update_mapping_from_spec(BACKEND_DEVICE_COUNT, "DEVICE_COUNT_FN")
+        update_mapping_from_spec(BACKEND_SUPPORTS_TRAINING, "SUPPORTS_TRAINING")

tests/models/test_layers_utils.py

@@ -25,7 +25,11 @@
 from diffusers.models.lora import LoRACompatibleLinear
 from diffusers.models.resnet import Downsample2D, ResnetBlock2D, Upsample2D
 from diffusers.models.transformer_2d import Transformer2DModel
-from diffusers.utils.testing_utils import torch_device
+from diffusers.utils.testing_utils import (
+    backend_manual_seed,
+    require_torch_accelerator_with_fp64,
+    torch_device,
+)
 
 
 class EmbeddingsTests(unittest.TestCase):
@@ -315,8 +319,7 @@ def test_restnet_with_kernel_sde_vp(self):
 class Transformer2DModelTests(unittest.TestCase):
     def test_spatial_transformer_default(self):
         torch.manual_seed(0)
-        if torch.cuda.is_available():
-            torch.cuda.manual_seed_all(0)
+        backend_manual_seed(torch_device, 0)
 
         sample = torch.randn(1, 32, 64, 64).to(torch_device)
         spatial_transformer_block = Transformer2DModel(
@@ -339,8 +342,7 @@ def test_spatial_transformer_default(self):
 
     def test_spatial_transformer_cross_attention_dim(self):
         torch.manual_seed(0)
-        if torch.cuda.is_available():
-            torch.cuda.manual_seed_all(0)
+        backend_manual_seed(torch_device, 0)
 
         sample = torch.randn(1, 64, 64, 64).to(torch_device)
         spatial_transformer_block = Transformer2DModel(
@@ -363,8 +365,7 @@ def test_spatial_transformer_cross_attention_dim(self):
 
     def test_spatial_transformer_timestep(self):
         torch.manual_seed(0)
-        if torch.cuda.is_available():
-            torch.cuda.manual_seed_all(0)
+        backend_manual_seed(torch_device, 0)
 
         num_embeds_ada_norm = 5
 
@@ -401,8 +402,7 @@ def test_spatial_transformer_timestep(self):
 
     def test_spatial_transformer_dropout(self):
         torch.manual_seed(0)
-        if torch.cuda.is_available():
-            torch.cuda.manual_seed_all(0)
+        backend_manual_seed(torch_device, 0)
 
         sample = torch.randn(1, 32, 64, 64).to(torch_device)
         spatial_transformer_block = (
@@ -427,11 +427,10 @@ def test_spatial_transformer_dropout(self):
         )
         assert torch.allclose(output_slice.flatten(), expected_slice, atol=1e-3)
 
-    @unittest.skipIf(torch_device == "mps", "MPS does not support float64")
+    @require_torch_accelerator_with_fp64
     def test_spatial_transformer_discrete(self):
         torch.manual_seed(0)
-        if torch.cuda.is_available():
-            torch.cuda.manual_seed_all(0)
+        backend_manual_seed(torch_device, 0)
 
         num_embed = 5
 

tests/models/test_modeling_common.py

@@ -35,6 +35,7 @@
     CaptureLogger,
     require_python39_or_higher,
     require_torch_2,
+    require_torch_accelerator_with_training,
     require_torch_gpu,
     run_test_in_subprocess,
     torch_device,
@@ -481,7 +482,7 @@ def test_model_from_pretrained(self):
 
         self.assertEqual(output_1.shape, output_2.shape)
 
-    @unittest.skipIf(torch_device == "mps", "Training is not supported in mps")
+    @require_torch_accelerator_with_training
     def test_training(self):
         init_dict, inputs_dict = self.prepare_init_args_and_inputs_for_common()
 
@@ -498,7 +499,7 @@ def test_training(self):
         loss = torch.nn.functional.mse_loss(output, noise)
         loss.backward()
 
-    @unittest.skipIf(torch_device == "mps", "Training is not supported in mps")
+    @require_torch_accelerator_with_training
     def test_ema_training(self):
         init_dict, inputs_dict = self.prepare_init_args_and_inputs_for_common()
 
@@ -562,7 +563,7 @@ def recursive_check(tuple_object, dict_object):
 
         recursive_check(outputs_tuple, outputs_dict)
 
-    @unittest.skipIf(torch_device == "mps", "Gradient checkpointing skipped on MPS")
+    @require_torch_accelerator_with_training
     def test_enable_disable_gradient_checkpointing(self):
         if not self.model_class._supports_gradient_checkpointing:
             return  # Skip test if model does not support gradient checkpointing

tests/models/test_models_prior.py

@@ -21,7 +21,14 @@
 from parameterized import parameterized
 
 from diffusers import PriorTransformer
-from diffusers.utils.testing_utils import enable_full_determinism, floats_tensor, slow, torch_all_close, torch_device
+from diffusers.utils.testing_utils import (
+    backend_empty_cache,
+    enable_full_determinism,
+    floats_tensor,
+    slow,
+    torch_all_close,
+    torch_device,
+)
 
 from .test_modeling_common import ModelTesterMixin
 
@@ -157,7 +164,7 @@ def tearDown(self):
         # clean up the VRAM after each test
         super().tearDown()
         gc.collect()
-        torch.cuda.empty_cache()
+        backend_empty_cache()
 
     @parameterized.expand(
         [

tests/models/test_models_unet_1d.py

@@ -18,7 +18,12 @@
 import torch
 
 from diffusers import UNet1DModel
-from diffusers.utils.testing_utils import floats_tensor, slow, torch_device
+from diffusers.utils.testing_utils import (
+    backend_manual_seed,
+    floats_tensor,
+    slow,
+    torch_device,
+)
 
 from .test_modeling_common import ModelTesterMixin, UNetTesterMixin
 
@@ -103,8 +108,7 @@ def test_from_pretrained_hub(self):
     def test_output_pretrained(self):
         model = UNet1DModel.from_pretrained("bglick13/hopper-medium-v2-value-function-hor32", subfolder="unet")
         torch.manual_seed(0)
-        if torch.cuda.is_available():
-            torch.cuda.manual_seed_all(0)
+        backend_manual_seed(torch_device, 0)
 
         num_features = model.config.in_channels
         seq_len = 16
@@ -244,8 +248,7 @@ def test_output_pretrained(self):
             "bglick13/hopper-medium-v2-value-function-hor32", output_loading_info=True, subfolder="value_function"
         )
         torch.manual_seed(0)
-        if torch.cuda.is_available():
-            torch.cuda.manual_seed_all(0)
+        backend_manual_seed(torch_device, 0)
 
         num_features = value_function.config.in_channels
         seq_len = 14

tests/models/test_models_unet_2d.py

@@ -24,6 +24,7 @@
 from diffusers.utils.testing_utils import (
     enable_full_determinism,
     floats_tensor,
+    require_torch_accelerator,
     slow,
     torch_all_close,
     torch_device,
@@ -153,15 +154,15 @@ def test_from_pretrained_hub(self):
 
         assert image is not None, "Make sure output is not None"
 
-    @unittest.skipIf(torch_device != "cuda", "This test is supposed to run on GPU")
+    @require_torch_accelerator
     def test_from_pretrained_accelerate(self):
         model, _ = UNet2DModel.from_pretrained("fusing/unet-ldm-dummy-update", output_loading_info=True)
         model.to(torch_device)
         image = model(**self.dummy_input).sample
 
         assert image is not None, "Make sure output is not None"
 
-    @unittest.skipIf(torch_device != "cuda", "This test is supposed to run on GPU")
+    @require_torch_accelerator
     def test_from_pretrained_accelerate_wont_change_results(self):
         # by defautl model loading will use accelerate as `low_cpu_mem_usage=True`
         model_accelerate, _ = UNet2DModel.from_pretrained("fusing/unet-ldm-dummy-update", output_loading_info=True)