Add AcceleratorRegistry

CHANGELOG.md

@@ -164,6 +164,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Added `Callback.state_dict()` and `Callback.load_state_dict()` methods ([#12232](https://github.com/PyTorchLightning/pytorch-lightning/pull/12232))
 
 
+- Added `AcceleratorRegistry` ([#12180](https://github.com/PyTorchLightning/pytorch-lightning/pull/12180))
+
+
 ### Changed
 
 - Drop PyTorch 1.7 support ([#12191](https://github.com/PyTorchLightning/pytorch-lightning/pull/12191))

pytorch_lightning/accelerators/__init__.py

@@ -14,4 +14,9 @@
 from pytorch_lightning.accelerators.cpu import CPUAccelerator  # noqa: F401
 from pytorch_lightning.accelerators.gpu import GPUAccelerator  # noqa: F401
 from pytorch_lightning.accelerators.ipu import IPUAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.registry import AcceleratorRegistry, call_register_accelerators  # noqa: F401
 from pytorch_lightning.accelerators.tpu import TPUAccelerator  # noqa: F401
+
+ACCELERATORS_BASE_MODULE = "pytorch_lightning.accelerators"
+
+call_register_accelerators(ACCELERATORS_BASE_MODULE)

pytorch_lightning/accelerators/accelerator.py

@@ -75,7 +75,6 @@ def auto_device_count() -> int:
     def is_available() -> bool:
         """Detect if the hardware is available."""
 
-    @staticmethod
-    @abstractmethod
-    def name() -> str:
-        """Name of the Accelerator."""
+    @classmethod
+    def register_accelerators(cls, accelerator_registry: Dict) -> None:
+        pass

pytorch_lightning/accelerators/cpu.py

@@ -63,7 +63,10 @@ def is_available() -> bool:
         """CPU is always available for execution."""
         return True
 
-    @staticmethod
-    def name() -> str:
-        """Name of the Accelerator."""
-        return "cpu"
+    @classmethod
+    def register_accelerators(cls, accelerator_registry: Dict) -> None:
+        accelerator_registry.register(
+            "cpu",
+            cls,
+            description=f"{cls.__class__.__name__}",
+        )

pytorch_lightning/accelerators/gpu.py

@@ -93,10 +93,13 @@ def auto_device_count() -> int:
     def is_available() -> bool:
         return torch.cuda.device_count() > 0
 
-    @staticmethod
-    def name() -> str:
-        """Name of the Accelerator."""
-        return "gpu"
+    @classmethod
+    def register_accelerators(cls, accelerator_registry: Dict) -> None:
+        accelerator_registry.register(
+            "gpu",
+            cls,
+            description=f"{cls.__class__.__name__}",
+        )
 
 
 def get_nvidia_gpu_stats(device: _DEVICE) -> Dict[str, float]:

pytorch_lightning/accelerators/ipu.py

@@ -47,7 +47,10 @@ def auto_device_count() -> int:
     def is_available() -> bool:
         return _IPU_AVAILABLE
 
-    @staticmethod
-    def name() -> str:
-        """Name of the Accelerator."""
-        return "ipu"
+    @classmethod
+    def register_accelerators(cls, accelerator_registry: Dict) -> None:
+        accelerator_registry.register(
+            "ipu",
+            cls,
+            description=f"{cls.__class__.__name__}",
+        )

pytorch_lightning/accelerators/registry.py

@@ -0,0 +1,122 @@
+# Copyright The PyTorch Lightning team.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import importlib
+from inspect import getmembers, isclass
+from typing import Any, Callable, Dict, List, Optional
+
+from pytorch_lightning.accelerators.accelerator import Accelerator
+from pytorch_lightning.utilities.exceptions import MisconfigurationException
+from pytorch_lightning.utilities.registry import _is_register_method_overridden
+
+
+class _AcceleratorRegistry(dict):
+    """This class is a Registry that stores information about the Accelerators.
+
+    The Accelerators are mapped to strings. These strings are names that identify
+    an accelerator, e.g., "gpu". It also returns Optional description and
+    parameters to initialize the Accelerator, which were defined during the
+    registration.
+
+    The motivation for having a AcceleratorRegistry is to make it convenient
+    for the Users to try different accelerators by passing mapped aliases
+    to the accelerator flag to the Trainer.
+
+    Example::
+
+        @AcceleratorRegistry.register("sota", description="Custom sota accelerator", a=1, b=True)
+        class SOTAAccelerator(Accelerator):
+            def __init__(self, a, b):
+                ...
+
+        or
+
+        AcceleratorRegistry.register("sota", SOTAAccelerator, description="Custom sota accelerator", a=1, b=True)
+    """
+
+    def register(
+        self,
+        name: str,
+        accelerator: Optional[Callable] = None,
+        description: str = "",
+        override: bool = False,
+        **init_params: Any,
+    ) -> Callable:
+        """Registers a accelerator mapped to a name and with required metadata.
+
+        Args:
+            name : the name that identifies a accelerator, e.g. "gpu"
+            accelerator : accelerator class
+            description : accelerator description
+            override : overrides the registered accelerator, if True
+            init_params: parameters to initialize the accelerator
+        """
+        if not (name is None or isinstance(name, str)):
+            raise TypeError(f"`name` must be a str, found {name}")
+
+        if name in self and not override:
+            raise MisconfigurationException(f"'{name}' is already present in the registry. HINT: Use `override=True`.")
+
+        data: Dict[str, Any] = {}
+
+        data["description"] = description
+        data["init_params"] = init_params
+
+        def do_register(name: str, accelerator: Callable) -> Callable:
+            data["accelerator"] = accelerator
+            data["accelerator_name"] = name
+            self[name] = data
+            return accelerator
+
+        if accelerator is not None:
+            return do_register(name, accelerator)
+
+        return do_register
+
+    def get(self, name: str, default: Optional[Any] = None) -> Any:
+        """Calls the registered accelerator with the required parameters and returns the accelerator object.
+
+        Args:
+            name (str): the name that identifies a accelerator, e.g. "gpu"
+        """
+        if name in self:
+            data = self[name]
+            return data["accelerator"](**data["init_params"])
+
+        if default is not None:
+            return default
+
+        err_msg = "'{}' not found in registry. Available names: {}"
+        available_names = self.available_accelerators()
+        raise KeyError(err_msg.format(name, available_names))
+
+    def remove(self, name: str) -> None:
+        """Removes the registered accelerator by name."""
+        self.pop(name)
+
+    def available_accelerators(self) -> List[str]:
+        """Returns a list of registered accelerators."""
+        return list(self.keys())
+
+    def __str__(self) -> str:
+        return "Registered Accelerators: {}".format(", ".join(self.available_accelerators()))
+
+
+AcceleratorRegistry = _AcceleratorRegistry()
+
+
+def call_register_accelerators(base_module: str) -> None:
+    module = importlib.import_module(base_module)
+    for _, mod in getmembers(module, isclass):
+        if issubclass(mod, Accelerator) and _is_register_method_overridden(mod, Accelerator, "register_accelerators"):
+            mod.register_accelerators(AcceleratorRegistry)

pytorch_lightning/accelerators/tpu.py

@@ -65,7 +65,10 @@ def auto_device_count() -> int:
     def is_available() -> bool:
         return _TPU_AVAILABLE
 
-    @staticmethod
-    def name() -> str:
-        """Name of the Accelerator."""
-        return "tpu"
+    @classmethod
+    def register_accelerators(cls, accelerator_registry: Dict) -> None:
+        accelerator_registry.register(
+            "tpu",
+            cls,
+            description=f"{cls.__class__.__name__}",
+        )

pytorch_lightning/strategies/__init__.py

@@ -11,8 +11,6 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from pathlib import Path
-
 from pytorch_lightning.strategies.bagua import BaguaStrategy  # noqa: F401
 from pytorch_lightning.strategies.ddp import DDPStrategy  # noqa: F401
 from pytorch_lightning.strategies.ddp2 import DDP2Strategy  # noqa: F401
@@ -31,7 +29,6 @@
 from pytorch_lightning.strategies.strategy_registry import call_register_strategies, StrategyRegistry  # noqa: F401
 from pytorch_lightning.strategies.tpu_spawn import TPUSpawnStrategy  # noqa: F401
 
-FILE_ROOT = Path(__file__).parent
 STRATEGIES_BASE_MODULE = "pytorch_lightning.strategies"
 
-call_register_strategies(FILE_ROOT, STRATEGIES_BASE_MODULE)
+call_register_strategies(STRATEGIES_BASE_MODULE)

pytorch_lightning/strategies/strategy_registry.py

@@ -12,13 +12,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import importlib
-import inspect
 from inspect import getmembers, isclass
-from pathlib import Path
 from typing import Any, Callable, Dict, List, Optional
 
 from pytorch_lightning.strategies.strategy import Strategy
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
+from pytorch_lightning.utilities.registry import _is_register_method_overridden
 
 
 class _StrategyRegistry(dict):
@@ -116,22 +115,8 @@ def __str__(self) -> str:
 StrategyRegistry = _StrategyRegistry()
 
 
-def is_register_strategies_overridden(strategy: type) -> bool:
-
-    method_name = "register_strategies"
-    strategy_attr = getattr(strategy, method_name)
-    previous_super_cls = inspect.getmro(strategy)[1]
-
-    if issubclass(previous_super_cls, Strategy):
-        super_attr = getattr(previous_super_cls, method_name)
-    else:
-        return False
-
-    return strategy_attr.__code__ is not super_attr.__code__
-
-
-def call_register_strategies(root: Path, base_module: str) -> None:
+def call_register_strategies(base_module: str) -> None:
     module = importlib.import_module(base_module)
     for _, mod in getmembers(module, isclass):
-        if issubclass(mod, Strategy) and is_register_strategies_overridden(mod):
+        if issubclass(mod, Strategy) and _is_register_method_overridden(mod, Strategy, "register_strategies"):
             mod.register_strategies(StrategyRegistry)

pytorch_lightning/trainer/connectors/accelerator_connector.py

@@ -23,6 +23,7 @@
 from pytorch_lightning.accelerators.cpu import CPUAccelerator
 from pytorch_lightning.accelerators.gpu import GPUAccelerator
 from pytorch_lightning.accelerators.ipu import IPUAccelerator
+from pytorch_lightning.accelerators.registry import AcceleratorRegistry
 from pytorch_lightning.accelerators.tpu import TPUAccelerator
 from pytorch_lightning.plugins import (
     ApexMixedPrecisionPlugin,
@@ -157,7 +158,7 @@ def __init__(
         # 1. Parsing flags
         # Get registered strategies, built-in accelerators and precision plugins
         self._registered_strategies = StrategyRegistry.available_strategies()
-        self._accelerator_types = ("tpu", "ipu", "gpu", "cpu")
+        self._accelerator_types = AcceleratorRegistry.available_accelerators()
         self._precision_types = ("16", "32", "64", "bf16", "mixed")
 
         # Raise an exception if there are conflicts between flags
@@ -486,32 +487,27 @@ def _choose_accelerator(self) -> str:
         return "cpu"
 
     def _set_parallel_devices_and_init_accelerator(self) -> None:
-        ACCELERATORS = {
-            "cpu": CPUAccelerator,
-            "gpu": GPUAccelerator,
-            "tpu": TPUAccelerator,
-            "ipu": IPUAccelerator,
-        }
         if isinstance(self._accelerator_flag, Accelerator):
             self.accelerator: Accelerator = self._accelerator_flag
         else:
             assert self._accelerator_flag is not None
             self._accelerator_flag = self._accelerator_flag.lower()
-            if self._accelerator_flag not in ACCELERATORS:
+            if self._accelerator_flag not in AcceleratorRegistry:
                 raise MisconfigurationException(
                     "When passing string value for the `accelerator` argument of `Trainer`,"
-                    f" it can only be one of {list(ACCELERATORS)}."
+                    f" it can only be one of {self._accelerator_types}."
                 )
-            accelerator_class = ACCELERATORS[self._accelerator_flag]
-            self.accelerator = accelerator_class()  # type: ignore[abstract]
+            self.accelerator = AcceleratorRegistry.get(self._accelerator_flag)
 
         if not self.accelerator.is_available():
-            available_accelerator = [acc_str for acc_str in list(ACCELERATORS) if ACCELERATORS[acc_str].is_available()]
+            available_accelerator = [
+                acc_str for acc_str in self._accelerator_types if AcceleratorRegistry.get(acc_str).is_available()
+            ]
             raise MisconfigurationException(
                 f"{self.accelerator.__class__.__qualname__} can not run on your system"
-                f" since {self.accelerator.name().upper()}s are not available."
-                " The following accelerator(s) is available and can be passed into"
-                f" `accelerator` argument of `Trainer`: {available_accelerator}."
+                " since the accelerator is not available. The following accelerator(s)"
+                " is available and can be passed into `accelerator` argument of"
+                f" `Trainer`: {available_accelerator}."
             )
 
         self._set_devices_flag_if_auto_passed()

pytorch_lightning/utilities/registry.py

@@ -0,0 +1,27 @@
+# Copyright The PyTorch Lightning team.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import inspect
+from typing import Any
+
+
+def _is_register_method_overridden(mod: type, base_cls: Any, method: str) -> bool:
+    mod_attr = getattr(mod, method)
+    previous_super_cls = inspect.getmro(mod)[1]
+
+    if issubclass(previous_super_cls, base_cls):
+        super_attr = getattr(previous_super_cls, method)
+    else:
+        return False
+
+    return mod_attr.__code__ is not super_attr.__code__

tests/accelerators/test_accelerator_connector.py

@@ -498,7 +498,8 @@ def test_accelerator_cpu(_):
     with pytest.raises(MisconfigurationException, match="You requested gpu:"):
         trainer = Trainer(gpus=1)
     with pytest.raises(
-        MisconfigurationException, match="GPUAccelerator can not run on your system since GPUs are not available."
+        MisconfigurationException,
+        match="GPUAccelerator can not run on your system since the accelerator is not available.",
     ):
         trainer = Trainer(accelerator="gpu")
     with pytest.raises(MisconfigurationException, match="You requested gpu:"):