Files
AstrAI/astrai/trainer/train_callback.py
T
ViperEkura 0546331637 fix: skip gradient checkpointing log when no modules configured
- GradientCheckpointingCallback.on_train_begin returns early on empty module list
- previously logged "Gradient checkpointing enabled" even when checkpointing was inactive, misleading profiling
2026-08-31 14:24:51 +08:00

378 lines
12 KiB
Python

import json
import logging
import os
import sys
import time
from functools import partial
from pathlib import Path
from typing import IO, Callable, List, Optional, Protocol, runtime_checkable
import torch
import torch.distributed as dist
import torch.nn as nn
from torch.utils.checkpoint import checkpoint as torch_checkpoint
from tqdm import tqdm
from astrai.factory import BaseFactory
from astrai.parallel import only_on_rank
from astrai.parallel.setup import get_current_device
from astrai.serialization import Checkpoint
from astrai.trainer.metric_util import (
ctx_get_grad_norm,
ctx_get_grad_snr,
ctx_get_loss,
ctx_get_lr,
ctx_get_moe_metric,
ctx_get_val_loss,
)
from astrai.trainer.train_context import TrainContext
logger = logging.getLogger(__name__)
@runtime_checkable
class TrainCallback(Protocol):
"""
Callback interface for trainer.
"""
def on_train_begin(self, context: TrainContext):
"""Called at the beginning of training."""
def on_train_end(self, context: TrainContext):
"""Called at the end of training."""
def on_epoch_begin(self, context: TrainContext):
"""Called at the beginning of each epoch."""
def on_epoch_end(self, context: TrainContext):
"""Called at the end of each epoch."""
def on_batch_begin(self, context: TrainContext):
"""Called at the beginning of each batch."""
def on_batch_end(self, context: TrainContext):
"""Called at the end of each batch."""
def on_optimizer_step(self, context: TrainContext):
"""Called on every optimizer step (sync step only)."""
def on_error(self, context: TrainContext):
"""Called when an error occurs during training."""
class CallbackFactory(BaseFactory[TrainCallback]):
"""Factory for registering and creating training callbacks.
Example:
@CallbackFactory.register("my_callback")
class MyCallback(TrainCallback):
...
callback = CallbackFactory.create("my_callback", **kwargs)
"""
@CallbackFactory.register("gradient_clipping")
class GradientClippingCallback(TrainCallback):
"""
Gradient clipping callback for trainer.
"""
def __init__(self, max_grad_norm: float):
self.max_grad_norm = max_grad_norm
def on_optimizer_step(self, context: TrainContext):
context.grad_norm = context.executor.clip_grad_norm(
context.model, self.max_grad_norm
)
@CallbackFactory.register("gradient_checkpointing")
class GradientCheckpointingCallback(TrainCallback):
"""
Activation checkpointing callback — trades compute for memory
by recomputing specified module activations during the backward pass.
Args:
modules: Module types to apply checkpointing to.
"""
def __init__(self, modules: Optional[List[type]] = None):
self.modules = tuple(modules) if modules else ()
def _enable(self, module: nn.Module):
if self.modules and isinstance(module, self.modules):
fn = module.forward
module._original_forward = fn
module.forward = lambda *a, **kw: torch_checkpoint(
fn, *a, use_reentrant=False, **kw
)
@staticmethod
def _disable(module: nn.Module):
if hasattr(module, "_original_forward"):
module.forward = module._original_forward
del module._original_forward
def on_train_begin(self, context: TrainContext):
if not self.modules:
return
context.model.apply(self._enable)
logger.info("Gradient checkpointing enabled")
def on_train_end(self, context: TrainContext):
context.model.apply(self._disable)
@CallbackFactory.register("checkpoint")
class CheckpointCallback(TrainCallback):
"""
Checkpoint callback for trainer.
"""
extra_keys = ("optimizer", "scheduler")
def __init__(
self,
save_dir: str,
interval: int,
weight_only: bool = False,
save_extra_fn: Optional[Callable[["TrainContext"], dict]] = None,
):
self.save_dir = save_dir
self.interval = interval
self.weight_only = weight_only
self.save_extra_fn = save_extra_fn or CheckpointCallback.save_extra
self.last_ckpt_step = None
def on_train_begin(self, context: TrainContext):
self.last_ckpt_step = context.optimizer_step
def _save_checkpoint(self, context: TrainContext):
self.last_ckpt_step = context.optimizer_step
with context.executor.checkpoint_context(context.model) as state_dict:
if state_dict is not None:
save_path = os.path.join(
self.save_dir,
f"epoch_{context.epoch}_step_{context.optimizer_step}",
)
extra = self.save_extra_fn(context)
meta = context.config.to_dict()
context.checkpoint = Checkpoint(
state_dict=state_dict,
epoch=context.epoch,
consumed_samples=context.consumed_samples,
config=context.model_config,
extra=extra,
meta=meta,
)
context.checkpoint.save(save_path)
def on_batch_end(self, context: TrainContext):
if context.optimizer_step - self.last_ckpt_step >= self.interval:
self._save_checkpoint(context)
def on_train_end(self, context: TrainContext):
if context.optimizer_step != self.last_ckpt_step:
self._save_checkpoint(context)
def on_error(self, context: TrainContext):
self._save_checkpoint(context)
@staticmethod
def save_extra(context: TrainContext) -> dict:
extra = {}
for name in CheckpointCallback.extra_keys:
obj = getattr(context, name, None)
if obj:
extra[name] = obj.state_dict()
return extra
@CallbackFactory.register("progress_bar")
class ProgressBarCallback(TrainCallback):
"""
Progress bar callback for trainer.
"""
def __init__(
self, num_epoch: int, log_interval: int = 100, file: Optional[IO[str]] = None
):
self.num_epoch = num_epoch
self.log_interval = log_interval
self.file = file
self.progress_bar: tqdm = None
@only_on_rank(0)
def on_epoch_begin(self, context: TrainContext):
total_steps = len(context.dataloader) // context.executor.grad_accum_steps
self.progress_bar = tqdm(
total=total_steps,
desc=f"Epoch {context.epoch + 1}/{self.num_epoch}",
dynamic_ncols=True,
file=self.file or sys.stdout,
)
@only_on_rank(0)
def on_optimizer_step(self, context: TrainContext):
postfix = {
"step": f"{context.optimizer_step:d}",
"loss": f"{context.loss:.4f}",
"lr": f"{context.optimizer.param_groups[-1]['lr']:.2e}",
}
if context.grad_norm is not None:
postfix["grad_norm"] = f"{context.grad_norm:.2f}"
if context.val_loss is not None:
postfix["val_loss"] = f"{context.val_loss:.4f}"
self.progress_bar.set_postfix(postfix)
self.progress_bar.update(1)
@only_on_rank(0)
def on_epoch_end(self, context: TrainContext):
_ = context
if self.progress_bar:
self.progress_bar.close()
@CallbackFactory.register("metric")
class MetricCallback(TrainCallback):
def __init__(
self,
ckpt_dir: str,
save_interval: int,
metrics: List[str] = None,
val_step: int = 0,
):
self.last_log_flush_step = None
self.save_interval = save_interval
self.metrics = metrics or ["loss", "lr"]
self.val_step = val_step
self._next_val_step = 0
self.ckpt_dir = Path(ckpt_dir) if ckpt_dir else Path.cwd() / "checkpoint"
self.log_cache = []
self._metric_funcs = {
"loss": ctx_get_loss,
"lr": ctx_get_lr,
"val_loss": ctx_get_val_loss,
"grad_norm": ctx_get_grad_norm,
"grad_snr": ctx_get_grad_snr,
"moe_aux_loss": partial(ctx_get_moe_metric, key="aux_loss"),
"router_entropy": partial(ctx_get_moe_metric, key="router_entropy"),
"dead_expert_fraction": partial(
ctx_get_moe_metric, key="dead_expert_fraction"
),
"load_imbalance_mean": partial(
ctx_get_moe_metric, key="load_imbalance_mean"
),
"load_imbalance_max": partial(ctx_get_moe_metric, key="load_imbalance_max"),
}
def _metrics(self, context: TrainContext, names):
metrics = dict(context.metrics)
for name in names:
metric_fn = self._metric_funcs.get(name)
if metric_fn is None:
continue
value = metric_fn(context)
if value is not None:
metrics[name] = value
selected = set(context.metrics) | set(names)
selected.discard("*")
result = {name: metrics[name] for name in selected if name in metrics}
if context.world_size > 1 and dist.is_initialized() and result:
metric_names = sorted(result)
values = torch.tensor(
[result[name] for name in metric_names],
dtype=torch.float32,
device=get_current_device(),
)
dist.all_reduce(values, op=dist.ReduceOp.SUM)
values /= context.world_size
result.update(zip(metric_names, values.tolist()))
return result
@only_on_rank(0)
def _append(self, event_type: str, context: TrainContext, **extra):
entry = {
"type": event_type,
"timestamp": time.strftime("%Y-%m-%dT%H:%M:%S"),
"epoch": context.epoch,
"step": context.optimizer_step,
"consumed_samples": context.consumed_samples,
**extra,
}
self.log_cache.append(entry)
def _run_validation(self, context: TrainContext) -> float:
context.model.eval()
total_loss = 0.0
num_batches = 0
with torch.no_grad():
for batch in context.val_dataloader:
loss_output = context.strategy(batch)
total_loss += loss_output["loss"].item()
num_batches += 1
if context.world_size > 1 and dist.is_initialized():
stats = torch.tensor(
[total_loss, float(num_batches)], device=get_current_device()
)
dist.all_reduce(stats, op=dist.ReduceOp.SUM)
avg_loss = (stats[0] / stats[1]).item()
else:
avg_loss = total_loss / max(num_batches, 1)
context.model.train()
return avg_loss
def on_train_begin(self, context: TrainContext):
self.last_log_flush_step = context.optimizer_step
@only_on_rank(0)
def _flush(self, epoch, step):
log_file = self.ckpt_dir / f"epoch_{epoch}_step_{step}" / "metric.jsonl"
log_file.parent.mkdir(parents=True, exist_ok=True)
with open(log_file, "w") as f:
for log in self.log_cache:
f.write(json.dumps(log) + "\n")
def on_optimizer_step(self, context):
context.grad_snr_tracker.update(context.model)
if (
context.val_dataloader is not None
and self.val_step > 0
and context.optimizer_step >= self._next_val_step
):
context.val_loss = self._run_validation(context)
self._next_val_step = context.optimizer_step + self.val_step
self._append("validation", context, val_loss=context.val_loss)
step_metrics = [m for m in self.metrics if m != "val_loss"]
self._append("step", context, **self._metrics(context, step_metrics))
if context.optimizer_step - self.last_log_flush_step >= self.save_interval:
self._flush(context.epoch, context.optimizer_step)
self.last_log_flush_step = context.optimizer_step
def on_epoch_end(self, context):
self._append("epoch", context)
def on_train_end(self, context):
if (
self.last_log_flush_step is None
or context.optimizer_step != self.last_log_flush_step
):
self._flush(context.epoch, context.optimizer_step)
self.last_log_flush_step = context.optimizer_step
def on_error(self, context):
self._flush(context.epoch, context.optimizer_step)