lightning/pytorch_lightning/plugins/precision/deepspeed_precision.py

62 lines
2.0 KiB
Python

from typing import Callable, Union
import torch
from torch.optim import Optimizer
from pytorch_lightning.core.lightning import LightningModule
from pytorch_lightning.plugins.precision.precision_plugin import PrecisionPlugin
from pytorch_lightning.utilities.model_helpers import is_overridden
from pytorch_lightning.utilities.warnings import WarningCache
warning_cache = WarningCache()
class DeepSpeedPrecisionPlugin(PrecisionPlugin):
def __init__(self, precision):
super().__init__()
self.precision = precision
def pre_optimizer_step(
self, pl_module: LightningModule, optimizer: Optimizer, optimizer_idx: int, lambda_closure: Callable, **kwargs
) -> bool:
deepspeed_engine = pl_module.trainer.model
# DeepSpeed not support closures.
lambda_closure()
if not pl_module.automatic_optimization:
pl_module.trainer.call_hook("on_after_backward")
deepspeed_engine.step()
return False
def backward(
self,
lightning_module: LightningModule,
closure_loss: torch.Tensor,
optimizer: torch.optim.Optimizer,
opt_idx: int,
should_accumulate: bool,
*args,
**kwargs,
):
if is_overridden('backward', lightning_module):
warning_cache.warn(
"Overridden backward hook in the LightningModule will be ignored since DeepSpeed handles"
"backward logic outside of the LightningModule"
)
# todo: hack around for deepspeed engine to call backward
deepspeed_engine = lightning_module.trainer.model
deepspeed_engine.backward(closure_loss, **kwargs)
# once backward has been applied, release graph
closure_loss = closure_loss.detach()
return closure_loss
def clip_gradients(self, optimizer: Optimizer, clip_val: Union[int, float], norm_type: float = float(2.0)):
"""
DeepSpeed handles clipping gradients via the training type plugin.
"""
pass