Remove AcceleratorConnector.tpu_cores and Deprecate Trainer.tpu_cores

CHANGELOG.md

@@ -606,6 +606,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Deprecated `Trainer.gpus` in favor of `Trainer.device_ids` or `Trainer.num_devices` ([#12436](https://github.com/PyTorchLightning/pytorch-lightning/pull/12436))
 
 
+- Deprecated `Trainer.tpu_cores` in favor of `Trainer.num_devices` ([#12437](https://github.com/PyTorchLightning/pytorch-lightning/pull/12437))
+
+
 ### Removed
 
 - Removed deprecated parameter `method` in `pytorch_lightning.utilities.model_helpers.is_overridden` ([#10507](https://github.com/PyTorchLightning/pytorch-lightning/pull/10507))
@@ -817,6 +820,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Removed `AcceleratorConnector.parallel_devices` property ([#12075](https://github.com/PyTorchLightning/pytorch-lightning/pull/12075))
 
 
+- Removed `AcceleratorConnector.tpu_cores` property ([#12437](https://github.com/PyTorchLightning/pytorch-lightning/pull/12437))
+
+
 ### Fixed
 
 - Fixed an issue where `ModelCheckpoint` could delete older checkpoints when `dirpath` has changed during resumed training ([#12045](https://github.com/PyTorchLightning/pytorch-lightning/pull/12045))

pytorch_lightning/callbacks/xla_stats_monitor.py

@@ -73,10 +73,10 @@ def on_train_start(self, trainer: "pl.Trainer", pl_module: "pl.LightningModule")
         if not trainer.loggers:
             raise MisconfigurationException("Cannot use XLAStatsMonitor callback with Trainer that has no logger.")
 
-        if isinstance(trainer.accelerator, TPUAccelerator):
+        if not isinstance(trainer.accelerator, TPUAccelerator):
             raise MisconfigurationException(
-                "You are using XLAStatsMonitor but are not running on TPU"
-                f" since `tpu_cores` attribute in Trainer is set to {trainer.tpu_cores}."
+                "You are using XLAStatsMonitor but are not running on TPU."
+                f" The accelerator is set to {trainer.accelerator.__class__.__name__}."
             )
 
         device = trainer.strategy.root_device

pytorch_lightning/trainer/trainer.py

@@ -1811,9 +1811,7 @@ def _log_device_info(self) -> None:
             f"GPU available: {torch.cuda.is_available()}, used: {isinstance(self.accelerator, GPUAccelerator)}"
         )
 
-        num_tpu_cores = (
-            self.tpu_cores if self.tpu_cores is not None and isinstance(self.accelerator, TPUAccelerator) else 0
-        )
+        num_tpu_cores = self.num_devices if isinstance(self.accelerator, TPUAccelerator) else 0
         rank_zero_info(f"TPU available: {_TPU_AVAILABLE}, using: {num_tpu_cores} TPU cores")
 
         num_ipus = self.num_devices if isinstance(self.accelerator, IPUAccelerator) else 0
@@ -2068,7 +2066,11 @@ def num_nodes(self) -> int:
     @property
     def device_ids(self) -> List[int]:
         """List of device indexes per node."""
-        devices = getattr(self.strategy, "parallel_devices", [self.strategy.root_device])
+        devices = (
+            self.strategy.parallel_devices
+            if isinstance(self.strategy, ParallelStrategy)
+            else [self.strategy.root_device]
+        )
         device_ids = []
         for idx, device in enumerate(devices):
             if isinstance(device, torch.device):
@@ -2100,7 +2102,11 @@ def root_gpu(self) -> Optional[int]:
 
     @property
     def tpu_cores(self) -> int:
-        return self._accelerator_connector.tpu_cores
+        rank_zero_deprecation(
+            "`Trainer.tpu_cores` is deprecated in v1.6 and will be removed in v1.8. "
+            "Please use `Trainer.num_devices` instead."
+        )
+        return self.num_devices if isinstance(self.accelerator, TPUAccelerator) else 0
 
     @property
     def ipus(self) -> int:

tests/accelerators/test_tpu.py

@@ -94,7 +94,6 @@ def test_accelerator_cpu_with_tpu_cores_flag():
 
 
 @RunIf(tpu=True)
-@pl_multi_process_test
 @pytest.mark.parametrize(["accelerator", "devices"], [("auto", 8), ("auto", "auto"), ("tpu", None)])
 def test_accelerator_tpu(accelerator, devices):
     assert TPUAccelerator.is_available()
@@ -103,7 +102,6 @@ def test_accelerator_tpu(accelerator, devices):
     assert isinstance(trainer.accelerator, TPUAccelerator)
     assert isinstance(trainer.strategy, TPUSpawnStrategy)
     assert trainer.num_devices == 8
-    assert trainer.tpu_cores == 8
 
 
 @RunIf(tpu=True)
@@ -114,13 +112,14 @@ def test_accelerator_tpu_with_tpu_cores_priority():
     with pytest.warns(UserWarning, match="The flag `devices=1` will be ignored,"):
         trainer = Trainer(accelerator="tpu", devices=1, tpu_cores=tpu_cores)
 
-    assert trainer.tpu_cores == tpu_cores
+    assert isinstance(trainer.accelerator, TPUAccelerator)
+    assert trainer.num_devices == tpu_cores
 
 
 @RunIf(tpu=True)
-@pl_multi_process_test
 def test_set_devices_if_none_tpu():
     trainer = Trainer(accelerator="tpu", tpu_cores=8)
+    assert isinstance(trainer.accelerator, TPUAccelerator)
     assert trainer.num_devices == 8
 
 

tests/deprecated_api/test_remove_1-7.py

@@ -20,6 +20,7 @@
 import pytest
 import torch
 
+import pytorch_lightning
 from pytorch_lightning import Callback, LightningDataModule, Trainer
 from pytorch_lightning.callbacks.gpu_stats_monitor import GPUStatsMonitor
 from pytorch_lightning.callbacks.lr_monitor import LearningRateMonitor
@@ -35,6 +36,7 @@
     TorchElasticEnvironment,
 )
 from pytorch_lightning.strategies import SingleDeviceStrategy
+from pytorch_lightning.utilities.exceptions import MisconfigurationException
 from tests.deprecated_api import _soft_unimport_module
 from tests.helpers import BoringModel
 from tests.helpers.datamodules import MNISTDataModule
@@ -393,8 +395,8 @@ def test_v1_7_0_deprecate_gpu_stats_monitor(tmpdir):
         _ = GPUStatsMonitor()
 
 
-@RunIf(tpu=True)
-def test_v1_7_0_deprecate_xla_stats_monitor(tmpdir):
+def test_v1_7_0_deprecate_xla_stats_monitor(monkeypatch):
+    monkeypatch.setattr(pytorch_lightning.callbacks.xla_stats_monitor, "_TPU_AVAILABLE", True)
     with pytest.deprecated_call(match="The `XLAStatsMonitor` callback was deprecated in v1.5"):
         _ = XLAStatsMonitor()
 
@@ -516,3 +518,17 @@ def post_dispatch(self, trainer):
 
     with pytest.deprecated_call(match=escape("`CustomPlugin.post_dispatch()` has been deprecated in v1.6")):
         CustomPlugin(torch.device("cpu"))
+
+
+def test_xla_stats_monitor_tpu_not_used(monkeypatch):
+    monkeypatch.setattr(pytorch_lightning.callbacks.xla_stats_monitor, "_TPU_AVAILABLE", True)
+    with pytest.deprecated_call(match="The `XLAStatsMonitor` callback was deprecated in v1.5"):
+        xla_stats = XLAStatsMonitor()
+
+    trainer = Trainer(accelerator="cpu", callbacks=[xla_stats])
+    model = BoringModel()
+    with pytest.raises(
+        MisconfigurationException,
+        match="You are using XLAStatsMonitor but are not running on TPU. The accelerator is set to CPUAccelerator.",
+    ):
+        trainer.fit(model)

tests/deprecated_api/test_remove_1-8.py

@@ -1126,3 +1126,14 @@ def test_trainer_gpus(monkeypatch, trainer_kwargs):
         " Please use `Trainer.num_devices` or `Trainer.device_ids` to get device information instead."
     ):
         assert trainer.gpus == trainer_kwargs["devices"]
+
+
+def test_trainer_tpu_cores(monkeypatch):
+    monkeypatch.setattr(pytorch_lightning.accelerators.tpu.TPUAccelerator, "is_available", lambda: True)
+    monkeypatch.setattr(pytorch_lightning.accelerators.tpu.TPUAccelerator, "parse_devices", lambda: 8)
+    trainer = Trainer(accelerator="TPU", devices=8)
+    with pytest.deprecated_call(
+        match="`Trainer.tpu_cores` is deprecated in v1.6 and will be removed in v1.8. "
+        "Please use `Trainer.num_devices` instead."
+    ):
+        trainer.tpu_cores == 8