delete the configurator in favor of argparse and clean up a lot of kwarg details to make them more consistent across all scripts

This commit is contained in:
Andrej Karpathy
2026-01-04 19:14:23 +00:00
parent 507d54224a
commit eb7bbc1b66
9 changed files with 546 additions and 450 deletions
+59 -48
View File
@@ -9,6 +9,7 @@ Or torchrun for training:
torchrun --standalone --nproc_per_node=8 -m scripts.mid_train -- --device_batch_size=16
"""
import argparse
from collections import deque
import os
os.environ["PYTORCH_ALLOC_CONF"] = "expandable_segments:True"
@@ -31,65 +32,75 @@ from tasks.customjson import CustomJSON
from tasks.spellingbee import SimpleSpelling, SpellingBee
# -----------------------------------------------------------------------------
run = "dummy" # wandb run name default ("dummy" is special - we won't log to wandb)
device_type = "" # cuda|cpu|mps (empty => autodetect)
model_tag = None # model tag to load the model from (base model or midtrained model)
step = None # step to load the model from (base model or midtrained model)
dtype = "bfloat16"
num_iterations = -1 # explicit number of steps of the optimization (-1 = disable)
max_seq_len = 2048
device_batch_size = 32
unembedding_lr = 0.004
embedding_lr = 0.2
matrix_lr = 0.02
init_lr_frac = 1.0 # initial learning rate is this fraction of the base learning rate
weight_decay = 0.0
eval_every = 150 # -1 = disable
eval_tokens = 20*524288
total_batch_size = 524288
dry_run = 0 # dry_run=1 is for experiments: we will log to wandb but we won't write checkpoints or report
config_keys = [k for k,v in globals().items() if not k.startswith('_') and isinstance(v, (int, float, bool, str))]
exec(open(os.path.join('nanochat', 'configurator.py')).read()) # overrides from command line or config file
user_config = {k: globals()[k] for k in config_keys} # possibly useful for logging
# CLI arguments
parser = argparse.ArgumentParser(description="Midtrain the model")
# Logging
parser.add_argument("--run", type=str, default="dummy", help="wandb run name ('dummy' disables wandb logging)")
# Runtime
parser.add_argument("--device_type", type=str, default="", help="cuda|cpu|mps (empty = autodetect)")
parser.add_argument("--dtype", type=str, default="bfloat16", help="float32|bfloat16")
# Model loading
parser.add_argument("--model_tag", type=str, default=None, help="model tag to load from")
parser.add_argument("--model_step", type=int, default=None, help="model step to load from")
# Training horizon
parser.add_argument("--num_iterations", type=int, default=-1, help="number of optimization steps (-1 = full epoch)")
# Batch sizes
parser.add_argument("--max_seq_len", type=int, default=2048, help="max context length")
parser.add_argument("--device_batch_size", type=int, default=32, help="per-device batch size")
parser.add_argument("--total_batch_size", type=int, default=524288, help="total batch size in tokens")
# Optimization
parser.add_argument("--embedding_lr", type=float, default=0.2, help="learning rate for embedding parameters (Adam)")
parser.add_argument("--unembedding_lr", type=float, default=0.004, help="learning rate for unembedding parameters (Adam)")
parser.add_argument("--matrix_lr", type=float, default=0.02, help="learning rate for matrix parameters (Muon)")
parser.add_argument("--weight_decay", type=float, default=0.0, help="weight decay for embedding/unembedding parameters (Adam)")
parser.add_argument("--init_lr_frac", type=float, default=1.0, help="initial LR as fraction of base LR")
# Evaluation
parser.add_argument("--eval_every", type=int, default=150, help="evaluate val bpb every N steps (-1 = disable)")
parser.add_argument("--eval_tokens", type=int, default=20*524288, help="number of tokens to evaluate val loss on")
# Output
parser.add_argument("--dry_run", action="store_true", help="log to wandb but skip checkpoints/report")
args = parser.parse_args()
user_config = vars(args).copy()
# -----------------------------------------------------------------------------
# Compute init
device_type = autodetect_device_type() if device_type == "" else device_type
device_type = autodetect_device_type() if args.device_type == "" else args.device_type
ddp, ddp_rank, ddp_local_rank, ddp_world_size, device = compute_init(device_type)
master_process = ddp_rank == 0
autocast_ctx = torch.amp.autocast(device_type=device_type, dtype=torch.bfloat16) if device_type == "cuda" else nullcontext()
ptdtype = torch.float32 if args.dtype == 'float32' else torch.bfloat16
autocast_ctx = torch.amp.autocast(device_type=device_type, dtype=ptdtype) if device_type == "cuda" else nullcontext()
synchronize = torch.cuda.synchronize if device_type == "cuda" else lambda: None
get_max_memory = torch.cuda.max_memory_allocated if device_type == "cuda" else lambda: 0
# wandb logging init
use_dummy_wandb = run == "dummy" or not master_process
wandb_run = DummyWandb() if use_dummy_wandb else wandb.init(project="nanochat-mid", name=run, config=user_config)
use_dummy_wandb = args.run == "dummy" or not master_process
wandb_run = DummyWandb() if use_dummy_wandb else wandb.init(project="nanochat-mid", name=args.run, config=user_config)
# Load the model and tokenizer
model, tokenizer, meta = load_model("base", device, phase="train", model_tag=model_tag, step=step)
model, tokenizer, meta = load_model("base", device, phase="train", model_tag=args.model_tag, step=args.model_step)
pretrain_batch_size = meta.get("device_batch_size", None)
if pretrain_batch_size is not None and device_batch_size > pretrain_batch_size:
if pretrain_batch_size is not None and args.device_batch_size > pretrain_batch_size:
print0(f"FOOTGUN WARNING: base model training used device_batch_size {pretrain_batch_size}, did you pass in a good --device_batch_size to this script?")
orig_model = model
model = torch.compile(model, dynamic=False)
depth = model.config.n_layer
num_flops_per_token = model.estimate_flops()
tokens_per_fwdbwd = device_batch_size * max_seq_len # tokens per iteration for a single rank
tokens_per_fwdbwd = args.device_batch_size * args.max_seq_len # tokens per iteration for a single rank
world_tokens_per_fwdbwd = tokens_per_fwdbwd * ddp_world_size # total tokens per iteration for all ranks
assert total_batch_size % world_tokens_per_fwdbwd == 0
grad_accum_steps = total_batch_size // world_tokens_per_fwdbwd
print0(f"Tokens / micro-batch / rank: {device_batch_size} x {max_seq_len} = {tokens_per_fwdbwd:,}")
assert args.total_batch_size % world_tokens_per_fwdbwd == 0
grad_accum_steps = args.total_batch_size // world_tokens_per_fwdbwd
print0(f"Tokens / micro-batch / rank: {args.device_batch_size} x {args.max_seq_len} = {tokens_per_fwdbwd:,}")
print0(f"Tokens / micro-batch: {world_tokens_per_fwdbwd:,}")
print0(f"Total batch size {total_batch_size:,} => gradient accumulation steps: {grad_accum_steps}")
print0(f"Total batch size {args.total_batch_size:,} => gradient accumulation steps: {grad_accum_steps}")
token_bytes = get_token_bytes(device=device)
# Initialize the Optimizer (Muon for Linear layers, AdamW for embedding and lm_head)
optimizers = model.setup_optimizers(unembedding_lr=unembedding_lr, embedding_lr=embedding_lr, matrix_lr=matrix_lr, weight_decay=weight_decay)
optimizers = model.setup_optimizers(unembedding_lr=args.unembedding_lr, embedding_lr=args.embedding_lr, matrix_lr=args.matrix_lr, weight_decay=args.weight_decay)
adamw_optimizer, muon_optimizer = optimizers
# Override the initial learning rate as a fraction of the base learning rate
for opt in optimizers:
for group in opt.param_groups:
group["lr"] = group["lr"] * init_lr_frac
group["lr"] = group["lr"] * args.init_lr_frac
group["initial_lr"] = group["lr"] # save the initial learning so we can decay easily later
# Midtraining data mixture and DataLoader
@@ -120,7 +131,7 @@ def mid_data_generator(split):
dataset = train_dataset if split == "train" else val_dataset
dataset_size = len(dataset)
assert dataset_size > 0
needed_tokens = device_batch_size * max_seq_len + 1 # to form one training batch of inputs,targets
needed_tokens = args.device_batch_size * args.max_seq_len + 1 # to form one training batch of inputs,targets
token_buffer = deque()
# CUDA supports memory pinning for faster transfers between CPU and GPU:
scratch = torch.empty(needed_tokens, dtype=torch.int64, pin_memory=(device_type == "cuda"))
@@ -139,18 +150,18 @@ def mid_data_generator(split):
last_step = True # toggle last_step to True, which will terminate the training loop
# Stopping condition to respect num_iterations, if given
it += 1
if 0 < num_iterations <= it and split == "train":
if 0 < args.num_iterations <= it and split == "train":
last_step = True # toggle last_step to True, which will terminate the training loop
# Build up inputs/targets and yield
for i in range(needed_tokens):
scratch[i] = token_buffer.popleft()
inputs_cpu = scratch[:-1].to(dtype=torch.int32)
targets_cpu = scratch[1:]
inputs = inputs_cpu.view(device_batch_size, max_seq_len).to(device=device, dtype=torch.int32, non_blocking=True)
targets = targets_cpu.view(device_batch_size, max_seq_len).to(device=device, dtype=torch.int64, non_blocking=True)
inputs = inputs_cpu.view(args.device_batch_size, args.max_seq_len).to(device=device, dtype=torch.int32, non_blocking=True)
targets = targets_cpu.view(args.device_batch_size, args.max_seq_len).to(device=device, dtype=torch.int64, non_blocking=True)
if split == "train":
if num_iterations > 0:
approx_progress = it / num_iterations # calculate progress from the max number of iterations
if args.num_iterations > 0:
approx_progress = it / args.num_iterations # calculate progress from the max number of iterations
else:
approx_progress = cursor / dataset_size # approximate progress as a fraction of the dataset
yield inputs, targets
@@ -179,7 +190,7 @@ ema_beta = 0.9 # EMA decay factor
total_training_time = 0 # total wall-clock time of training
step = 0
while True:
flops_so_far = num_flops_per_token * total_batch_size * step
flops_so_far = num_flops_per_token * args.total_batch_size * step
# Synchronize last_step across all ranks to avoid hangs in the distributed setting
if ddp:
@@ -188,10 +199,10 @@ while True:
last_step = bool(last_step_tensor.item())
# once in a while: evaluate the val bpb (all ranks participate)
if eval_every > 0 and (last_step or step % eval_every == 0):
if args.eval_every > 0 and (last_step or step % args.eval_every == 0):
model.eval()
val_loader = build_val_loader()
eval_steps = eval_tokens // (device_batch_size * max_seq_len * ddp_world_size)
eval_steps = args.eval_tokens // (args.device_batch_size * args.max_seq_len * ddp_world_size)
with autocast_ctx:
val_bpb = evaluate_bpb(model, val_loader, eval_steps, token_bytes)
print0(f"Step {step:05d} | Validation bpb: {val_bpb:.4f}")
@@ -206,8 +217,8 @@ while True:
model.train()
# save checkpoint at the end of the run (only on master process)
if master_process and last_step and not dry_run:
output_dirname = model_tag if model_tag else f"d{depth}" # e.g. d12
if master_process and last_step and not args.dry_run:
output_dirname = args.model_tag if args.model_tag else f"d{depth}" # e.g. d12
checkpoint_dir = os.path.join(base_dir, "mid_checkpoints", output_dirname)
save_checkpoint(
checkpoint_dir,
@@ -218,7 +229,7 @@ while True:
"step": step,
"val_bpb": val_bpb, # loss at last step
"model_config": {
"sequence_len": max_seq_len,
"sequence_len": args.max_seq_len,
"vocab_size": tokenizer.get_vocab_size(),
"n_layer": depth,
"n_head": model.config.n_head,
@@ -268,8 +279,8 @@ while True:
smooth_train_loss = ema_beta * smooth_train_loss + (1 - ema_beta) * train_loss.item() # EMA the training loss
debiased_smooth_loss = smooth_train_loss / (1 - ema_beta**(step + 1)) # debias the EMA
pct_done = 100 * progress
tok_per_sec = int(total_batch_size / dt)
flops_per_sec = num_flops_per_token * total_batch_size / dt
tok_per_sec = int(args.total_batch_size / dt)
flops_per_sec = num_flops_per_token * args.total_batch_size / dt
promised_flops_per_sec_h100 = 989e12 * ddp_world_size # bfloat16 H100 SXM and without 2:4 sparsity
mfu = 100 * flops_per_sec / promised_flops_per_sec_h100 # in %
if step > 10:
@@ -293,7 +304,7 @@ print0(f"Total training time: {total_training_time/60:.2f}m")
print0(f"Minimum validation bpb: {min_val_bpb:.4f}")
# Log to report
if not dry_run:
if not args.dry_run:
from nanochat.report import get_report
get_report().log(section="Midtraining", data=[
user_config, # CLI args