remove deprecation of gpu string parsing behavior (#8770)

CHANGELOG.md

@@ -33,6 +33,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 ### Changed
 
+- Parsing of the `gpus` Trainer argument has changed: `gpus="n"` (str) no longer selects the GPU index n and instead selects the first n devices. ([#8770](https://github.com/PyTorchLightning/pytorch-lightning/pull/8770))
+
+
 - Replace `iteration_count` and other index attributes in the loops with progress dataclasses ([#8477](https://github.com/PyTorchLightning/pytorch-lightning/pull/8477))
 
 

docs/source/advanced/multi_gpu.rst

@@ -216,19 +216,15 @@ Note in particular the difference between `gpus=0`, `gpus=[0]` and `gpus="0"`.
 +---------------+-----------+---------------------+---------------------------------+
 | [1, 3]        | list      | [1, 3]              | GPUs 1 and 3                    |
 +---------------+-----------+---------------------+---------------------------------+
-| "0"           | str       | [0]                 | GPU 0                           |
+| "0"           | str       | None                | CPU                             |
 +---------------+-----------+---------------------+---------------------------------+
-| "3"           | str       | [3]                 | GPU 3 (will change in v1.5)     |
+| "3"           | str       | [0, 1, 2]           | first 3 GPUs                    |
 +---------------+-----------+---------------------+---------------------------------+
 | "1, 3"        | str       | [1, 3]              | GPUs 1 and 3                    |
 +---------------+-----------+---------------------+---------------------------------+
 | "-1"          | str       | [0, 1, 2, ...]      | all available GPUs              |
 +---------------+-----------+---------------------+---------------------------------+
 
-.. warning::
-    The behavior for :code:`gpus="3"` (str) will change. Currently it selects the GPU with index 3, but will
-    select the first 3 GPUs from v1.5.
-
 .. note::
 
     When specifying number of gpus as an integer ``gpus=k``, setting the trainer flag

pytorch_lightning/utilities/device_parser.py

@@ -11,15 +11,13 @@
 # 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 operator
 from typing import Any, List, MutableSequence, Optional, Tuple, Union
 
 import torch
 
 from pytorch_lightning.plugins.environments import TorchElasticEnvironment
-from pytorch_lightning.utilities import _TPU_AVAILABLE, rank_zero_deprecation
+from pytorch_lightning.utilities import _TPU_AVAILABLE
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
-from pytorch_lightning.utilities.imports import _compare_version
 
 
 def determine_root_gpu_device(gpus: List[int]) -> Optional[int]:
@@ -72,11 +70,7 @@ def parse_gpu_ids(gpus: Optional[Union[int, str, List[int]]]) -> Optional[List[i
     _check_data_type(gpus)
 
     # Handle the case when no gpus are requested
-    if gpus is None or isinstance(gpus, int) and gpus == 0:
-        return None
-
-    if _compare_version("pytorch_lightning", operator.ge, "1.5") and isinstance(gpus, str) and gpus.strip() == "0":
-        # TODO: in v1.5 combine this with the above if statement
+    if gpus is None or isinstance(gpus, int) and gpus == 0 or str(gpus).strip() == "0":
         return None
 
     # We know user requested GPUs therefore if some of the
@@ -134,16 +128,7 @@ def _normalize_parse_gpu_string_input(s: Union[int, str, List[int]]) -> Union[in
         return -1
     if "," in s:
         return [int(x.strip()) for x in s.split(",") if len(x) > 0]
-    num_gpus = int(s.strip())
-    if _compare_version("pytorch_lightning", operator.lt, "1.5"):
-        rank_zero_deprecation(
-            f"Parsing of the Trainer argument gpus='{s}' (string) will change in the future."
-            " In the current version of Lightning, this will select"
-            f" CUDA device with index {num_gpus}, but from v1.5 it will select gpus"
-            f" {list(range(num_gpus))} (same as gpus={s} (int))."
-        )
-        return [num_gpus]
-    return num_gpus
+    return int(s.strip())
 
 
 def _sanitize_gpu_ids(gpus: List[int]) -> List[int]:

tests/deprecated_api/test_remove_1-5.py

@@ -12,7 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 """Test deprecated functionality which will be removed in v1.5.0"""
-import operator
 import os
 from typing import Any, Dict
 from unittest import mock
@@ -26,8 +25,6 @@ from pytorch_lightning.core.decorators import auto_move_data
 from pytorch_lightning.loggers import WandbLogger
 from pytorch_lightning.plugins import DeepSpeedPlugin
 from pytorch_lightning.profiler import AdvancedProfiler, BaseProfiler, PyTorchProfiler, SimpleProfiler
-from pytorch_lightning.utilities import device_parser
-from pytorch_lightning.utilities.imports import _compare_version
 from tests.deprecated_api import no_deprecated_call
 from tests.helpers import BoringDataModule, BoringModel
 from tests.helpers.runif import RunIf
@@ -204,25 +201,6 @@ def test_v1_5_0_lighting_module_grad_norm(tmpdir):
         model.grad_norm(2)
 
 
-@pytest.mark.xfail(
-    condition=_compare_version("pytorch_lightning", operator.ge, "1.5"), reason="parsing of string will change in v1.5"
-)
-@mock.patch("torch.cuda.device_count", return_value=4)
-def test_v1_5_0_trainer_gpus_str_parsing(*_):
-    # TODO: when removing this, make sure docs in docs/advanced/multi-gpu.rst reflect the new
-    #   behavior regarding GPU selection. Ping @awaelchli if unsure.
-    with pytest.deprecated_call(match=r"Parsing of the Trainer argument gpus='3' .* will change."):
-        Trainer(gpus="3", accelerator="ddp_spawn")
-
-    with pytest.deprecated_call(match=r"Parsing of the Trainer argument gpus='3' .* will change."):
-        gpus = device_parser.parse_gpu_ids("3")
-        assert gpus == [3]
-
-    with pytest.deprecated_call(match=r"Parsing of the Trainer argument gpus='0' .* will change."):
-        gpus = device_parser.parse_gpu_ids("0")
-        assert gpus == [0]
-
-
 def test_v1_5_0_datamodule_setter():
     model = BoringModel()
     datamodule = BoringDataModule()

tests/models/test_gpu.py

@@ -195,8 +195,8 @@ def test_determine_root_gpu_device(gpus, expected_root_gpu):
         pytest.param([0], [0]),
         pytest.param([1, 3], [1, 3]),
         pytest.param((1, 3), [1, 3]),
-        pytest.param("0", None, marks=pytest.mark.skipif(PL_VERSION_LT_1_5, reason="available from v1.5")),
-        pytest.param("3", [0, 1, 2], marks=pytest.mark.skipif(PL_VERSION_LT_1_5, reason="available from v1.5")),
+        pytest.param("0", None),
+        pytest.param("3", [0, 1, 2]),
         pytest.param("1, 3", [1, 3]),
         pytest.param("2,", [2]),
         pytest.param("-1", list(range(PRETEND_N_OF_GPUS)), id="'-1' - use all gpus"),