GC every n steps (#2209)

src/axolotl/core/trainer_builder.py

@@ -56,6 +56,7 @@
 from axolotl.utils import is_comet_available, is_mlflow_available
 from axolotl.utils.callbacks import (
     EvalFirstStepCallback,
+    GCCallback,
     GPUStatsCallback,
     LossWatchDogCallback,
     SaveAxolotlConfigtoWandBCallback,
@@ -1452,6 +1453,8 @@ def get_callbacks(self):
         if self.cfg.loss_watchdog_threshold is not None:
             callbacks.append(LossWatchDogCallback(self.cfg))
 
+        if self.cfg.gc_steps:
+            callbacks.append(GCCallback(gc_steps=self.cfg.gc_steps))
         callbacks.append(SaveModelCallback())
 
         return callbacks

src/axolotl/utils/callbacks/__init__.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import gc
 import logging
 import math
 import os
@@ -842,3 +843,17 @@ def on_train_end(  # pylint: disable=unused-argument
     ):
         control.should_save = True
         return control
+
+
+class GCCallback(TrainerCallback):
+    """Callback to garbage collect torch cache"""
+
+    def __init__(self, gc_steps=None):
+        self.gc_steps = gc_steps
+
+    def on_step_end(
+        self, args, state, control, **kwargs  # pylint: disable=unused-argument
+    ):
+        if state.global_step % self.gc_steps == 0:
+            torch.cuda.empty_cache()
+            gc.collect()

src/axolotl/utils/config/models/input/v0_4_1/__init__.py

@@ -666,6 +666,8 @@ class Config:
     loss_watchdog_threshold: Optional[float] = None
     loss_watchdog_patience: Optional[int] = None
 
+    gc_steps: Optional[int] = None
+
     bf16: Optional[Union[Literal["auto"], bool]] = "auto"
     fp16: Optional[bool] = None
     bfloat16: Optional[bool] = None  # for non-AMP cases