The psutil package is now required for CPU monitoring (#17010)

(cherry picked from commit 8d586c6)

src/pytorch_lightning/CHANGELOG.md

@@ -20,6 +20,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Fixed `num_nodes` not being set for `DDPFullyShardedNativeStrategy` ([#17160](https://github.com/Lightning-AI/lightning/pull/17160))
 
 
+- The `psutil` package is now required for CPU monitoring ([#17010](https://github.com/Lightning-AI/lightning/pull/17010))
+
+
 ## [1.9.4] - 2023-03-01
 
 ### Added

src/pytorch_lightning/accelerators/cpu.py

@@ -14,12 +14,12 @@
 from typing import Any, Dict, List, Union
 
 import torch
+from lightning_utilities.core.imports import RequirementCache
 
 from lightning_fabric.accelerators.cpu import _parse_cpu_cores
 from lightning_fabric.utilities.types import _DEVICE
 from pytorch_lightning.accelerators.accelerator import Accelerator
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
-from pytorch_lightning.utilities.imports import _PSUTIL_AVAILABLE
 
 
 class CPUAccelerator(Accelerator):
@@ -76,13 +76,13 @@ def register_accelerators(cls, accelerator_registry: Dict) -> None:
 _CPU_VM_PERCENT = "cpu_vm_percent"
 _CPU_PERCENT = "cpu_percent"
 _CPU_SWAP_PERCENT = "cpu_swap_percent"
+_PSUTIL_AVAILABLE = RequirementCache("psutil")
 
 
 def get_cpu_stats() -> Dict[str, float]:
     if not _PSUTIL_AVAILABLE:
         raise ModuleNotFoundError(
-            "Fetching CPU device stats requires `psutil` to be installed."
-            " Install it by running `pip install -U psutil`."
+            f"Fetching CPU device stats requires `psutil` to be installed. {str(_PSUTIL_AVAILABLE)}"
         )
     import psutil
 

src/pytorch_lightning/accelerators/mps.py

@@ -19,8 +19,8 @@
 from lightning_fabric.utilities.device_parser import _parse_gpu_ids
 from lightning_fabric.utilities.types import _DEVICE
 from pytorch_lightning.accelerators.accelerator import Accelerator
+from pytorch_lightning.accelerators.cpu import _PSUTIL_AVAILABLE
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
-from pytorch_lightning.utilities.imports import _PSUTIL_AVAILABLE
 
 
 class MPSAccelerator(Accelerator):
@@ -84,8 +84,7 @@ def register_accelerators(cls, accelerator_registry: Dict) -> None:
 def get_device_stats() -> Dict[str, float]:
     if not _PSUTIL_AVAILABLE:
         raise ModuleNotFoundError(
-            "Fetching M1 device stats requires `psutil` to be installed."
-            " Install it by running `pip install -U psutil`."
+            f"Fetching MPS device stats requires `psutil` to be installed. {str(_PSUTIL_AVAILABLE)}"
         )
     import psutil
 

src/pytorch_lightning/callbacks/device_stats_monitor.py

@@ -21,10 +21,9 @@
 from typing import Any, Dict, Optional
 
 import pytorch_lightning as pl
+from pytorch_lightning.accelerators.cpu import _PSUTIL_AVAILABLE
 from pytorch_lightning.callbacks.callback import Callback
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
-from pytorch_lightning.utilities.imports import _PSUTIL_AVAILABLE
-from pytorch_lightning.utilities.rank_zero import rank_zero_warn
 from pytorch_lightning.utilities.types import STEP_OUTPUT
 
 
@@ -36,14 +35,14 @@ class DeviceStatsMonitor(Callback):
 
     Args:
         cpu_stats: if ``None``, it will log CPU stats only if the accelerator is CPU.
-            It will raise a warning if ``psutil`` is not installed till v1.9.0.
-            If ``True``, it will log CPU stats regardless of the accelerator, and it will
-            raise an exception if ``psutil`` is not installed.
+            If ``True``, it will log CPU stats regardless of the accelerator.
             If ``False``, it will not log CPU stats regardless of the accelerator.
 
     Raises:
         MisconfigurationException:
             If ``Trainer`` has no logger.
+        ModuleNotFoundError:
+            If ``psutil`` is not installed and CPU stats are monitored.
 
     Example:
         >>> from pytorch_lightning import Trainer
@@ -70,13 +69,9 @@ def setup(
         # warn in setup to warn once
         device = trainer.strategy.root_device
         if self._cpu_stats is None and device.type == "cpu" and not _PSUTIL_AVAILABLE:
-            # TODO: raise an exception from v1.9
-            rank_zero_warn(
-                "`DeviceStatsMonitor` will not log CPU stats as `psutil` is not installed."
-                " To install `psutil`, run `pip install psutil`."
-                " It will raise an exception if `psutil` is not installed post v1.9.0."
+            raise ModuleNotFoundError(
+                f"`DeviceStatsMonitor` cannot log CPU stats as `psutil` is not installed. {str(_PSUTIL_AVAILABLE)} "
             )
-            self._cpu_stats = False
 
     def _get_and_log_device_stats(self, trainer: "pl.Trainer", key: str) -> None:
         if not trainer._logger_connector.should_update_logs:

src/pytorch_lightning/utilities/imports.py

@@ -31,7 +31,7 @@
 _HIVEMIND_AVAILABLE = package_available("hivemind")
 _KINETO_AVAILABLE = torch.profiler.kineto_available()
 _OMEGACONF_AVAILABLE = package_available("omegaconf")
-_PSUTIL_AVAILABLE = package_available("psutil")
+_POPTORCH_AVAILABLE = package_available("poptorch")
 _RICH_AVAILABLE = package_available("rich") and compare_version("rich", operator.ge, "10.2.2")
 _TORCH_QUANTIZE_AVAILABLE = bool([eg for eg in torch.backends.quantized.supported_engines if eg != "none"])
 _TORCHVISION_AVAILABLE = RequirementCache("torchvision")

tests/tests_pytorch/callbacks/test_device_stats_monitor.py

@@ -165,8 +165,7 @@ def test_device_stats_monitor_warning_when_psutil_not_available(monkeypatch, tmp
     monitor = DeviceStatsMonitor()
     trainer = Trainer(logger=CSVLogger(tmp_path))
     assert trainer.strategy.root_device == torch.device("cpu")
-    # TODO: raise an exception from v1.9
-    with pytest.warns(UserWarning, match="psutil` is not installed"):
+    with pytest.raises(ModuleNotFoundError, match="psutil` is not installed"):
         monitor.setup(trainer, Mock(), "fit")
 
 

tests/tests_pytorch/helpers/runif.py

@@ -22,6 +22,7 @@
 from packaging.version import Version
 
 from lightning_fabric.accelerators.cuda import num_cuda_devices
+from pytorch_lightning.accelerators.cpu import _PSUTIL_AVAILABLE
 from pytorch_lightning.accelerators.hpu import _HPU_AVAILABLE
 from pytorch_lightning.accelerators.ipu import _IPU_AVAILABLE
 from pytorch_lightning.accelerators.mps import MPSAccelerator
@@ -37,7 +38,6 @@
     _HIVEMIND_AVAILABLE,
     _OMEGACONF_AVAILABLE,
     _ONNX_AVAILABLE,
-    _PSUTIL_AVAILABLE,
     _TORCH_GREATER_EQUAL_2_0,
     _TORCH_QUANTIZE_AVAILABLE,
 )