LoRA: add training callbacks (#414)

* LoRA: add training callbacks

* LoRA: add trained tokens print & callback

llms/mlx_lm/lora.py

@@ -7,7 +7,6 @@ import mlx.optimizers as optim
 import numpy as np
 from mlx.utils import tree_flatten
 
-from .tuner.lora import LoRALinear
 from .tuner.trainer import TrainingArgs, evaluate, train
 from .tuner.utils import linear_to_lora_layers
 from .utils import generate, load

llms/mlx_lm/tuner/trainer.py

@@ -119,6 +119,17 @@ def evaluate(
     return np.sum(all_losses) / ntokens
 
 
+class TrainingCallback:
+
+    def on_train_loss_report(self, steps: int, loss: float, it_sec: float, tokens_sec: float, trained_tokens: int):
+        """Called to report training loss at specified intervals."""
+        pass
+
+    def on_val_loss_report(self, steps: int, loss: float, val_time: float):
+        """Called to report validation loss at specified intervals or the beginning."""
+        pass
+
+
 def train(
     model,
     tokenizer,
@@ -127,8 +138,11 @@ def train(
     val_dataset,
     args: TrainingArgs = TrainingArgs(),
     loss: callable = default_loss,
-    iterate_batches: callable = iterate_batches
+    iterate_batches: callable = iterate_batches,
+    training_callback=None,
 ):
+    print(f"Starting training..., iters: {args.iters}")
+
     # Create checkpoints directory if it does not exist
     if not os.path.exists("checkpoints"):
         os.makedirs("checkpoints")
@@ -138,7 +152,7 @@ def train(
 
     losses = []
     n_tokens = 0
-    print("Starting training..., iters:", args.iters)
+    trained_tokens = 0
     # Main training loop
     start = time.perf_counter()
     for it, batch in zip(
@@ -168,11 +182,19 @@ def train(
             train_loss = np.mean(losses)
 
             stop = time.perf_counter()
+            it_sec = args.steps_per_report / (stop - start)
+            tokens_sec = float(n_tokens) / (stop - start)
+            trained_tokens += n_tokens
             print(
                 f"Iter {it + 1}: Train loss {train_loss:.3f}, "
-                f"It/sec {args.steps_per_report / (stop - start):.3f}, "
-                f"Tokens/sec {float(n_tokens) / (stop - start):.3f}"
+                f"It/sec {it_sec:.3f}, "
+                f"Tokens/sec {tokens_sec:.3f}, "
+                f"Trained Tokens {trained_tokens}"
             )
+
+            if training_callback is not None:
+                training_callback.on_train_loss_report(it + 1, train_loss, it_sec, tokens_sec, trained_tokens)
+
             losses = []
             n_tokens = 0
             start = time.perf_counter()
@@ -190,12 +212,16 @@ def train(
                 max_seq_length=args.max_seq_length,
                 iterate_batches=iterate_batches
             )
+            val_time = time.perf_counter() - stop
             print(
                 f"Iter {it + 1}: "
                 f"Val loss {val_loss:.3f}, "
-                f"Val took {(time.perf_counter() - stop):.3f}s"
+                f"Val took {val_time:.3f}s"
             )
 
+            if training_callback is not None:
+                training_callback.on_val_loss_report(it + 1, val_loss, val_time)
+
             start = time.perf_counter()
 
         # Save adapter weights if needed
@@ -205,6 +231,7 @@ def train(
             print(
                 f"Iter {it + 1}: Saved adapter weights to {os.path.join(checkpoint_adapter_file)}."
             )
+
     # save final adapter weights
     save_adapter(model=model, adapter_file=args.adapter_file)
     print(f"Saved final adapter weights to {os.path.join(args.adapter_file)}.")