refactor: rename canto-backend → backend, canto-frontend → frontend

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
2026-04-07 18:11:00 +08:00
parent 2fa9c1fcb6
commit 60489eab59
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# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
# This source code is licensed under the license found in the
# LICENSE file in the root directory of this source tree.
import itertools
import sys
import time
from pathlib import Path
from typing import Optional, Tuple
import torch
import torch._dynamo.config
import torch._inductor.config
def device_sync(device):
if "cuda" in device:
torch.cuda.synchronize(device)
elif ("cpu" in device) or ("mps" in device):
pass
else:
print(f"device={device} is not yet suppported")
torch._inductor.config.coordinate_descent_tuning = True
torch._inductor.config.triton.unique_kernel_names = True
torch._inductor.config.fx_graph_cache = True # Experimental feature to reduce compilation times, will be on by default in future
default_device = 'cuda' if torch.cuda.is_available() else 'cpu'
# support running without installing as a package
wd = Path(__file__).parent.parent.resolve()
sys.path.append(str(wd))
from model import Transformer
from tokenizer import get_tokenizer
def multinomial_sample_one_no_sync(probs_sort): # Does multinomial sampling without a cuda synchronization
q = torch.empty_like(probs_sort).exponential_(1)
return torch.argmax(probs_sort / q, dim=-1, keepdim=True).to(dtype=torch.int)
def logits_to_probs(logits, temperature: float = 1.0, top_k: Optional[int] = None):
logits = logits / max(temperature, 1e-5)
if top_k is not None:
v, _ = torch.topk(logits, min(top_k, logits.size(-1)))
pivot = v.select(-1, -1).unsqueeze(-1)
logits = torch.where(logits < pivot, -float("Inf"), logits)
probs = torch.nn.functional.softmax(logits, dim=-1)
return probs
def sample(logits, temperature: float = 1.0, top_k: Optional[int] = None):
probs = logits_to_probs(logits[0, -1], temperature, top_k)
idx_next = multinomial_sample_one_no_sync(probs)
return idx_next, probs
def prefill(model: Transformer, x: torch.Tensor, input_pos: torch.Tensor, **sampling_kwargs) -> torch.Tensor:
# input_pos: [B, S]
logits = model(x, input_pos)
return sample(logits, **sampling_kwargs)[0]
def decode_one_token(model: Transformer, x: torch.Tensor, input_pos: torch.Tensor, **sampling_kwargs) -> Tuple[torch.Tensor, torch.Tensor]:
# input_pos: [B, 1]
assert input_pos.shape[-1] == 1
logits = model(x, input_pos)
return sample(logits, **sampling_kwargs)
def decode_n_tokens(model: Transformer, cur_token: torch.Tensor, input_pos: torch.Tensor, num_new_tokens: int, callback=lambda _: _, **sampling_kwargs):
new_tokens, new_probs = [], []
for i in range(num_new_tokens):
with torch.backends.cuda.sdp_kernel(enable_flash=False, enable_mem_efficient=False, enable_math=True): # Actually better for Inductor to codegen attention here
next_token, next_prob = decode_one_token(
model, cur_token, input_pos, **sampling_kwargs
)
input_pos += 1
new_tokens.append(next_token.clone())
callback(new_tokens[-1])
new_probs.append(next_prob.clone())
cur_token = next_token.view(1, -1)
return new_tokens, new_probs
def model_forward(model, x, input_pos):
return model(x, input_pos)
def speculative_decode(
model: Transformer,
draft_model: Transformer,
cur_token: torch.Tensor,
input_pos: int,
speculate_k: int,
**sampling_kwargs
) -> torch.Tensor:
# draft model inference sequentially
device = cur_token.device
orig_input_pos = torch.tensor([input_pos], dtype=torch.int64, device=cur_token.device)
draft_tokens, draft_probs = decode_n_tokens(draft_model, cur_token.view(1, -1), orig_input_pos.clone(), speculate_k, **sampling_kwargs)
draft_tokens = torch.cat(draft_tokens)
# parallel inference on target model using draft tokens
target_logits = model_forward(
model,
torch.cat([cur_token.view(1), draft_tokens]).view(1, -1),
torch.arange(input_pos, input_pos + speculate_k + 1, device=cur_token.device)
)
target_probs = logits_to_probs(target_logits[0], **sampling_kwargs)
draft_probs = torch.stack(draft_probs)
# q: target prob, p: draft prob
# q >= p: always accept draft token
# q < p: q/p prob to accept draft token
p = draft_probs[torch.arange(0, speculate_k, device=device), draft_tokens]
q = target_probs[torch.arange(0, speculate_k, device=device), draft_tokens]
accept_draft_prob = torch.minimum(torch.ones(()), q[:speculate_k]/ p)
rejected_locations = (torch.rand_like(accept_draft_prob) > accept_draft_prob).nonzero()
if rejected_locations.shape[0] == 0: # All draft tokens have been accepted
accept_length = speculate_k + 1
last_token = multinomial_sample_one_no_sync(target_probs[-1])
# fill last token into draft model
model_forward(
draft_model,
draft_tokens[-1].view(1, -1),
orig_input_pos + speculate_k,
)
return torch.cat([draft_tokens, last_token])
else:
accept_length = rejected_locations[0].item()
p = draft_probs[accept_length]
q = target_probs[accept_length]
new = q - p
new = torch.where(new > 0, new, 0.0)
new = new / new.sum()
next_token = multinomial_sample_one_no_sync(new)
return torch.cat([draft_tokens[:accept_length], next_token])
@torch.no_grad()
def generate(
model: Transformer,
prompt: torch.Tensor,
max_new_tokens: int,
*,
interactive: bool,
draft_model: Transformer,
speculate_k: Optional[int] = 8,
callback = lambda x: x,
**sampling_kwargs
) -> torch.Tensor:
"""
Takes a conditioning sequence (prompt) as input and continues to generate as many tokens as requested.
"""
is_speculative = draft_model is not None
# create an empty tensor of the expected final shape and fill in the current tokens
T = prompt.size(0)
T_new = T + max_new_tokens
if interactive:
max_seq_length = 350
else:
max_seq_length = min(T_new, model.config.block_size)
device, dtype = prompt.device, prompt.dtype
max_seq_length = max_seq_length + speculate_k + 1 if is_speculative else max_seq_length
with torch.device(device):
model.setup_caches(max_batch_size=1, max_seq_length=max_seq_length)
if is_speculative and draft_model is not model:
draft_model.setup_caches(max_batch_size=1, max_seq_length=max_seq_length)
# create an empty tensor of the expected final shape and fill in the current tokens
empty = torch.empty(T_new, dtype=dtype, device=device)
empty[:T] = prompt
seq = empty
input_pos = torch.arange(0, T, device=device)
next_token = prefill(model, prompt.view(1, -1), input_pos, **sampling_kwargs).clone()
if is_speculative:
prefill(draft_model, prompt.view(1, -1), input_pos, **sampling_kwargs)
seq[T] = next_token
input_pos = torch.tensor([T], device=device, dtype=torch.int)
accept_counts = [0] * (speculate_k + 1)
if is_speculative:
input_pos = input_pos.item() # for speculative decoding easier to keep on host
while input_pos < T_new - 1:
cur_token = next_token.view(())
next_tokens = speculative_decode(
model, draft_model, cur_token, input_pos, speculate_k, **sampling_kwargs
)
accept_counts[len(next_tokens) - 1] += 1
num_added = min(T_new - input_pos - 1, len(next_tokens))
seq[input_pos + 1 : input_pos + num_added + 1] = next_tokens[: num_added]
for i in next_tokens[: num_added,]:
callback(i)
input_pos = input_pos + num_added
next_token = next_tokens[-1]
else:
generated_tokens, _ = decode_n_tokens(model, next_token.view(1, -1), input_pos, max_new_tokens - 1, callback=callback, **sampling_kwargs)
seq[T + 1:] = torch.cat(generated_tokens)
generate_stats = {
'accept_counts': accept_counts
}
return seq, generate_stats
def encode_tokens(tokenizer, string, bos=True, device=default_device):
tokens = tokenizer.encode(string)
if bos:
tokens = [tokenizer.bos_id()] + tokens
return torch.tensor(tokens, dtype=torch.int, device=device)
def _load_model(checkpoint_path, device, precision, use_tp):
use_cuda = 'cuda' in device
with torch.device('meta'):
model = Transformer.from_name(checkpoint_path.parent.name)
if "int8" in str(checkpoint_path):
print("Using int8 weight-only quantization!")
from quantize import WeightOnlyInt8QuantHandler
simple_quantizer = WeightOnlyInt8QuantHandler(model)
model = simple_quantizer.convert_for_runtime()
if "int4" in str(checkpoint_path):
print("Using int4 weight-only quantization!")
path_comps = checkpoint_path.name.split(".")
groupsize = int(path_comps[-2][1:])
from quantize import WeightOnlyInt4QuantHandler
simple_quantizer = WeightOnlyInt4QuantHandler(model, groupsize)
model = simple_quantizer.convert_for_runtime()
checkpoint = torch.load(str(checkpoint_path), mmap=True, weights_only=True)
if "model" in checkpoint and "stories" in str(checkpoint_path):
checkpoint = checkpoint["model"]
model.load_state_dict(checkpoint, assign=True)
if use_tp:
from tp import apply_tp
print("Applying tensor parallel to model ...")
apply_tp(model)
model = model.to(device=device, dtype=precision)
return model.eval()
def _get_model_size(model):
model_size = 0
for name, child in model.named_children():
if not isinstance(child, torch.nn.Embedding):
model_size += sum(
[
p.numel() * p.dtype.itemsize
for p in itertools.chain(child.parameters(), child.buffers())
]
)
return model_size
B_INST, E_INST = "[INST]", "[/INST]"
def main(
prompt: str = "Hello, my name is",
interactive: bool = False,
num_samples: int = 5,
max_new_tokens: int = 100,
top_k: int = 200,
temperature: float = 0.8,
checkpoint_path: Path = Path("checkpoints/meta-Transformer/Transformer-2-7b-chat-hf/model.pth"),
compile: bool = True,
compile_prefill: bool = False,
profile: Optional[Path] = None,
draft_checkpoint_path: Optional[Path] = None,
speculate_k: int = 5,
device=default_device,
) -> None:
"""Generates text samples based on a pre-trained Transformer model and tokenizer.
"""
assert checkpoint_path.is_file(), checkpoint_path
tokenizer_path = checkpoint_path.parent / "tokenizer.model"
assert tokenizer_path.is_file(), str(tokenizer_path)
global print
from tp import maybe_init_dist
rank = maybe_init_dist()
use_tp = rank is not None
if use_tp:
if rank != 0:
# only print on rank 0
print = lambda *args, **kwargs: None
print(f"Using device={device}")
precision = torch.bfloat16
is_speculative = draft_checkpoint_path is not None
is_chat = "chat" in str(checkpoint_path)
print("Loading model ...")
t0 = time.time()
model = _load_model(checkpoint_path, device, precision, use_tp)
if is_speculative:
draft_model = _load_model(draft_checkpoint_path, device, precision, use_tp)
else:
draft_model = None
device_sync(device=device) # MKG
print(f"Time to load model: {time.time() - t0:.02f} seconds")
tokenizer = get_tokenizer(tokenizer_path, checkpoint_path)
encoded = encode_tokens(tokenizer, prompt, bos=True, device=device)
prompt_length = encoded.size(0)
torch.manual_seed(1234)
model_size = _get_model_size(model)
if compile:
if is_speculative and use_tp: # and ("cuda" in device):
torch._inductor.config.triton.cudagraph_trees = False # Bug with cudagraph trees in this case
if is_speculative:
global model_forward, logits_to_prob
model_forward = torch.compile(model_forward, mode="reduce-overhead", fullgraph=True)
global decode_one_token, prefill
decode_one_token = torch.compile(decode_one_token, mode="reduce-overhead", fullgraph=True)
# Uncomment to squeeze more perf out of prefill
if compile_prefill:
prefill = torch.compile(prefill, fullgraph=True, dynamic=True)
aggregate_metrics = {
'tokens_per_sec': [],
'accept_counts': [],
}
start = -1 if compile else 0
for i in range(start, num_samples):
device_sync(device=device) # MKG
if i >= 0 and interactive:
prompt = input("What is your prompt? ")
if is_chat:
prompt = f"{B_INST} {prompt.strip()} {E_INST}"
encoded = encode_tokens(tokenizer, prompt, bos=True, device=device)
if interactive and i >= 0:
buffer = []
period_id = tokenizer.encode('.')[0]
done_generating = False
def callback(x):
nonlocal done_generating
if done_generating:
return
buffer.append(tokenizer.decode([period_id] + x.tolist())[1:])
if x.item() == tokenizer.eos_id():
done_generating = True
if len(buffer) == 4 or done_generating:
print(''.join(buffer), end='', flush=True)
buffer.clear()
# print(, end='', flush=True)
else:
callback = lambda x : x
t0 = time.perf_counter()
import contextlib
if (i != num_samples - 1 or not profile) or (use_tp and rank != 0):
prof = contextlib.nullcontext()
else:
torch.profiler._utils._init_for_cuda_graphs()
prof = torch.profiler.profile()
with prof:
y, metrics = generate(
model,
encoded,
max_new_tokens,
draft_model=draft_model,
speculate_k=speculate_k,
interactive=interactive,
callback=callback,
temperature=temperature,
top_k=top_k,
)
aggregate_metrics['accept_counts'].append(metrics['accept_counts'])
if i == -1:
print(f"Compilation time: {time.perf_counter() - t0:.2f} seconds")
continue
if hasattr(prof, "export_chrome_trace"):
if use_tp:
prof.export_chrome_trace(f"{profile}_rank_{rank}.json")
else:
prof.export_chrome_trace(f"{profile}.json")
device_sync(device=device) # MKG
t = time.perf_counter() - t0
if not interactive:
print(tokenizer.decode(y.tolist()))
else:
print()
tokens_generated = y.size(0) - prompt_length
tokens_sec = tokens_generated / t
aggregate_metrics['tokens_per_sec'].append(tokens_sec)
print(f"Time for inference {i + 1}: {t:.02f} sec total, {tokens_sec:.02f} tokens/sec")
print(f"Bandwidth achieved: {model_size * tokens_sec / 1e9:.02f} GB/s")
print("==========")
if is_speculative:
counts_aggregated = [sum(i) for i in zip(*aggregate_metrics['accept_counts'])]
acceptance_probs = [i/sum(counts_aggregated) for i in counts_aggregated]
print(f"Acceptance probs: {acceptance_probs}")
print(f"Mean Accepted: {sum([idx * i for idx, i in enumerate(counts_aggregated)])/sum(counts_aggregated)}")
print(f"Average tokens/sec: {torch.mean(torch.tensor(aggregate_metrics['tokens_per_sec'])).item():.2f}")
print(f"Memory used: {torch.cuda.max_memory_reserved() / 1e9:.02f} GB")
if __name__ == '__main__':
import argparse
parser = argparse.ArgumentParser(description='Your CLI description.')
parser.add_argument('--prompt', type=str, default="Hello, my name is", help='Input prompt.')
parser.add_argument('--interactive', action='store_true', help='Whether to launch in interactive mode')
parser.add_argument('--num_samples', type=int, default=5, help='Number of samples.')
parser.add_argument('--max_new_tokens', type=int, default=200, help='Maximum number of new tokens.')
parser.add_argument('--top_k', type=int, default=200, help='Top-k for sampling.')
parser.add_argument('--temperature', type=float, default=0.8, help='Temperature for sampling.')
parser.add_argument('--checkpoint_path', type=Path, default=Path("checkpoints/meta-Transformer/Transformer-2-7b-chat-hf/model.pth"), help='Model checkpoint path.')
parser.add_argument('--compile', action='store_true', help='Whether to compile the model.')
parser.add_argument('--compile_prefill', action='store_true', help='Whether to compile the prefill (improves prefill perf, but higher compile times)')
parser.add_argument('--profile', type=Path, default=None, help='Profile path.')
parser.add_argument('--speculate_k', type=int, default=5, help='Speculative execution depth.')
parser.add_argument('--draft_checkpoint_path', type=Path, default=None, help='Draft checkpoint path.')
parser.add_argument('--device', type=str, default=default_device, help='Device to use')
args = parser.parse_args()
main(
args.prompt, args.interactive, args.num_samples, args.max_new_tokens, args.top_k,
args.temperature, args.checkpoint_path, args.compile, args.compile_prefill, args.profile, args.draft_checkpoint_path,
args.speculate_k, args.device
)

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# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
# This source code is licensed under the license found in the
# LICENSE file in the root directory of this source tree.
from dataclasses import dataclass
from typing import Optional
import torch
import torch.nn as nn
from torch import Tensor
from torch.nn import functional as F
def find_multiple(n: int, k: int) -> int:
if n % k == 0:
return n
return n + k - (n % k)
class AdaptiveLayerNorm(nn.Module):
r"""Adaptive Layer Normalization"""
def __init__(self, d_model, norm) -> None:
super(AdaptiveLayerNorm, self).__init__()
self.project_layer = nn.Linear(d_model, 2 * d_model)
self.norm = norm
self.d_model = d_model
self.eps = self.norm.eps
def forward(self, input: Tensor, embedding: Tensor = None) -> Tensor:
if embedding is None:
return self.norm(input)
weight, bias = torch.split(
self.project_layer(embedding),
split_size_or_sections=self.d_model,
dim=-1,
)
return weight * self.norm(input) + bias
@dataclass
class ModelArgs:
block_size: int = 2048
vocab_size: int = 32000
n_layer: int = 32
n_head: int = 32
dim: int = 4096
intermediate_size: int = None
n_local_heads: int = -1
head_dim: int = 64
rope_base: float = 10000
norm_eps: float = 1e-5
has_cross_attention: bool = False
context_dim: int = 0
uvit_skip_connection: bool = False
time_as_token: bool = False
def __post_init__(self):
if self.n_local_heads == -1:
self.n_local_heads = self.n_head
if self.intermediate_size is None:
hidden_dim = 4 * self.dim
n_hidden = int(2 * hidden_dim / 3)
self.intermediate_size = find_multiple(n_hidden, 256)
# self.head_dim = self.dim // self.n_head
@classmethod
def from_name(cls, name: str):
if name in transformer_configs:
return cls(**transformer_configs[name])
# fuzzy search
config = [config for config in transformer_configs if config.lower() in str(name).lower()]
# We may have two or more configs matched (e.g. "7B" and "Mistral-7B"). Find the best config match,
# take longer name (as it have more symbols matched)
if len(config) > 1:
config.sort(key=len, reverse=True)
assert len(config[0]) != len(config[1]), name # make sure only one 'best' match
return cls(**transformer_configs[config[0]])
transformer_configs = {
"CodeLlama-7b-Python-hf": dict(block_size=16384, vocab_size=32000, n_layer=32, dim=4096, rope_base=1000000),
"7B": dict(n_layer=32, n_head=32, dim=4096),
"13B": dict(n_layer=40, n_head=40, dim=5120),
"30B": dict(n_layer=60, n_head=52, dim=6656),
"34B": dict(n_layer=48, n_head=64, dim=8192, vocab_size=32000, n_local_heads=8, intermediate_size=22016,
rope_base=1000000), # CodeLlama-34B-Python-hf
"70B": dict(n_layer=80, n_head=64, dim=8192, n_local_heads=8, intermediate_size=28672),
"Mistral-7B": dict(n_layer=32, n_head=32, n_local_heads=8, dim=4096, intermediate_size=14336, vocab_size=32000),
"stories15M": dict(n_layer=6, n_head=6, dim=288),
"stories110M": dict(n_layer=12, n_head=12, dim=768),
"llama-3-8b": dict(block_size=8192, n_layer=32, n_head=32, n_local_heads=8, dim=4096, intermediate_size=14336,
vocab_size=128256, rope_base=500000),
"llama-3-70b": dict(block_size=8192, n_layer=80, n_head=64, n_local_heads=8, dim=8192, intermediate_size=28672,
vocab_size=128256, rope_base=500000),
}
class KVCache(nn.Module):
def __init__(self, max_batch_size, max_seq_length, n_heads, head_dim, dtype=torch.bfloat16):
super().__init__()
cache_shape = (max_batch_size, n_heads, max_seq_length, head_dim)
self.register_buffer('k_cache', torch.zeros(cache_shape, dtype=dtype))
self.register_buffer('v_cache', torch.zeros(cache_shape, dtype=dtype))
def update(self, input_pos, k_val, v_val):
# input_pos: [S], k_val: [B, H, S, D]
assert input_pos.shape[0] == k_val.shape[2]
k_out = self.k_cache
v_out = self.v_cache
k_out[:, :, input_pos] = k_val
v_out[:, :, input_pos] = v_val
return k_out, v_out
class Transformer(nn.Module):
def __init__(self, config: ModelArgs) -> None:
super().__init__()
self.config = config
self.layers = nn.ModuleList(TransformerBlock(config) for _ in range(config.n_layer))
self.norm = AdaptiveLayerNorm(config.dim, RMSNorm(config.dim, eps=config.norm_eps))
self.freqs_cis: Optional[Tensor] = None
self.mask_cache: Optional[Tensor] = None
self.max_batch_size = -1
self.max_seq_length = -1
def setup_caches(self, max_batch_size, max_seq_length, use_kv_cache=True):
if self.max_seq_length >= max_seq_length and self.max_batch_size >= max_batch_size:
return
head_dim = self.config.dim // self.config.n_head
max_seq_length = find_multiple(max_seq_length, 8)
self.max_seq_length = max_seq_length
self.max_batch_size = max_batch_size
dtype = self.norm.project_layer.weight.dtype
device = self.norm.project_layer.weight.device
if not self.training and use_kv_cache:
for b in self.layers:
b.attention.kv_cache = KVCache(max_batch_size, max_seq_length, self.config.n_local_heads, head_dim, dtype).to(device)
self.freqs_cis = precompute_freqs_cis(self.config.block_size, self.config.head_dim,
self.config.rope_base, dtype).to(device)
self.causal_mask = torch.tril(torch.ones(self.max_seq_length, self.max_seq_length, dtype=torch.bool)).to(device)
self.use_kv_cache = use_kv_cache
self.uvit_skip_connection = self.config.uvit_skip_connection
if self.uvit_skip_connection:
self.layers_emit_skip = [i for i in range(self.config.n_layer) if i < self.config.n_layer // 2]
self.layers_receive_skip = [i for i in range(self.config.n_layer) if i > self.config.n_layer // 2]
else:
self.layers_emit_skip = []
self.layers_receive_skip = []
def forward(self,
x: Tensor,
c: Tensor,
input_pos: Optional[Tensor] = None,
mask: Optional[Tensor] = None,
context: Optional[Tensor] = None,
context_input_pos: Optional[Tensor] = None,
cross_attention_mask: Optional[Tensor] = None,
) -> Tensor:
assert self.freqs_cis is not None, "Caches must be initialized first"
if mask is None: # in case of non-causal model
if not self.training and self.use_kv_cache:
mask = self.causal_mask[None, None, input_pos]
else:
mask = self.causal_mask[None, None, input_pos]
mask = mask[..., input_pos]
freqs_cis = self.freqs_cis[input_pos]
if context is not None:
context_freqs_cis = self.freqs_cis[context_input_pos]
else:
context_freqs_cis = None
skip_in_x_list = []
for i, layer in enumerate(self.layers):
if self.uvit_skip_connection and i in self.layers_receive_skip:
skip_in_x = skip_in_x_list.pop(-1)
else:
skip_in_x = None
x = layer(x, c, input_pos, freqs_cis, mask, context, context_freqs_cis, cross_attention_mask, skip_in_x)
if self.uvit_skip_connection and i in self.layers_emit_skip:
skip_in_x_list.append(x)
x = self.norm(x, c)
return x
@classmethod
def from_name(cls, name: str):
return cls(ModelArgs.from_name(name))
class TransformerBlock(nn.Module):
def __init__(self, config: ModelArgs) -> None:
super().__init__()
self.attention = Attention(config)
self.feed_forward = FeedForward(config)
self.ffn_norm = AdaptiveLayerNorm(config.dim, RMSNorm(config.dim, eps=config.norm_eps))
self.attention_norm = AdaptiveLayerNorm(config.dim, RMSNorm(config.dim, eps=config.norm_eps))
if config.has_cross_attention:
self.has_cross_attention = True
self.cross_attention = Attention(config, is_cross_attention=True)
self.cross_attention_norm = AdaptiveLayerNorm(config.dim, RMSNorm(config.dim, eps=config.norm_eps))
else:
self.has_cross_attention = False
if config.uvit_skip_connection:
self.skip_in_linear = nn.Linear(config.dim * 2, config.dim)
self.uvit_skip_connection = True
else:
self.uvit_skip_connection = False
self.time_as_token = config.time_as_token
def forward(self,
x: Tensor,
c: Tensor,
input_pos: Tensor,
freqs_cis: Tensor,
mask: Tensor,
context: Optional[Tensor] = None,
context_freqs_cis: Optional[Tensor] = None,
cross_attention_mask: Optional[Tensor] = None,
skip_in_x: Optional[Tensor] = None,
) -> Tensor:
c = None if self.time_as_token else c
if self.uvit_skip_connection and skip_in_x is not None:
x = self.skip_in_linear(torch.cat([x, skip_in_x], dim=-1))
h = x + self.attention(self.attention_norm(x, c), freqs_cis, mask, input_pos)
if self.has_cross_attention:
h = h + self.cross_attention(self.cross_attention_norm(h, c), freqs_cis, cross_attention_mask, input_pos, context, context_freqs_cis)
out = h + self.feed_forward(self.ffn_norm(h, c))
return out
class Attention(nn.Module):
def __init__(self, config: ModelArgs, is_cross_attention: bool = False):
super().__init__()
assert config.dim % config.n_head == 0
total_head_dim = (config.n_head + 2 * config.n_local_heads) * config.head_dim
# key, query, value projections for all heads, but in a batch
if is_cross_attention:
self.wq = nn.Linear(config.dim, config.n_head * config.head_dim, bias=False)
self.wkv = nn.Linear(config.context_dim, 2 * config.n_local_heads * config.head_dim, bias=False)
else:
self.wqkv = nn.Linear(config.dim, total_head_dim, bias=False)
self.wo = nn.Linear(config.head_dim * config.n_head, config.dim, bias=False)
self.kv_cache = None
self.n_head = config.n_head
self.head_dim = config.head_dim
self.n_local_heads = config.n_local_heads
self.dim = config.dim
# self._register_load_state_dict_pre_hook(self.load_hook)
# def load_hook(self, state_dict, prefix, *args):
# if prefix + "wq.weight" in state_dict:
# wq = state_dict.pop(prefix + "wq.weight")
# wk = state_dict.pop(prefix + "wk.weight")
# wv = state_dict.pop(prefix + "wv.weight")
# state_dict[prefix + "wqkv.weight"] = torch.cat([wq, wk, wv])
def forward(self,
x: Tensor,
freqs_cis: Tensor,
mask: Tensor,
input_pos: Optional[Tensor] = None,
context: Optional[Tensor] = None,
context_freqs_cis: Optional[Tensor] = None,
) -> Tensor:
bsz, seqlen, _ = x.shape
kv_size = self.n_local_heads * self.head_dim
if context is None:
q, k, v = self.wqkv(x).split([kv_size, kv_size, kv_size], dim=-1)
context_seqlen = seqlen
else:
q = self.wq(x)
k, v = self.wkv(context).split([kv_size, kv_size], dim=-1)
context_seqlen = context.shape[1]
q = q.view(bsz, seqlen, self.n_head, self.head_dim)
k = k.view(bsz, context_seqlen, self.n_local_heads, self.head_dim)
v = v.view(bsz, context_seqlen, self.n_local_heads, self.head_dim)
q = apply_rotary_emb(q, freqs_cis)
k = apply_rotary_emb(k, context_freqs_cis if context_freqs_cis is not None else freqs_cis)
q, k, v = map(lambda x: x.transpose(1, 2), (q, k, v))
if self.kv_cache is not None:
k, v = self.kv_cache.update(input_pos, k, v)
k = k.repeat_interleave(self.n_head // self.n_local_heads, dim=1)
v = v.repeat_interleave(self.n_head // self.n_local_heads, dim=1)
y = F.scaled_dot_product_attention(q, k, v, attn_mask=mask, dropout_p=0.0)
y = y.transpose(1, 2).contiguous().view(bsz, seqlen, self.head_dim * self.n_head)
y = self.wo(y)
return y
class FeedForward(nn.Module):
def __init__(self, config: ModelArgs) -> None:
super().__init__()
self.w1 = nn.Linear(config.dim, config.intermediate_size, bias=False)
self.w3 = nn.Linear(config.dim, config.intermediate_size, bias=False)
self.w2 = nn.Linear(config.intermediate_size, config.dim, bias=False)
def forward(self, x: Tensor) -> Tensor:
return self.w2(F.silu(self.w1(x)) * self.w3(x))
class RMSNorm(nn.Module):
def __init__(self, dim: int, eps: float = 1e-5):
super().__init__()
self.eps = eps
self.weight = nn.Parameter(torch.ones(dim))
def _norm(self, x):
return x * torch.rsqrt(torch.mean(x * x, dim=-1, keepdim=True) + self.eps)
def forward(self, x: Tensor) -> Tensor:
output = self._norm(x.float()).type_as(x)
return output * self.weight
def precompute_freqs_cis(
seq_len: int, n_elem: int, base: int = 10000,
dtype: torch.dtype = torch.bfloat16
) -> Tensor:
freqs = 1.0 / (base ** (torch.arange(0, n_elem, 2)[: (n_elem // 2)].float() / n_elem))
t = torch.arange(seq_len, device=freqs.device)
freqs = torch.outer(t, freqs)
freqs_cis = torch.polar(torch.ones_like(freqs), freqs)
cache = torch.stack([freqs_cis.real, freqs_cis.imag], dim=-1)
return cache.to(dtype=dtype)
def apply_rotary_emb(x: Tensor, freqs_cis: Tensor) -> Tensor:
xshaped = x.float().reshape(*x.shape[:-1], -1, 2)
freqs_cis = freqs_cis.view(1, xshaped.size(1), 1, xshaped.size(3), 2)
x_out2 = torch.stack(
[
xshaped[..., 0] * freqs_cis[..., 0] - xshaped[..., 1] * freqs_cis[..., 1],
xshaped[..., 1] * freqs_cis[..., 0] + xshaped[..., 0] * freqs_cis[..., 1],
],
-1,
)
x_out2 = x_out2.flatten(3)
return x_out2.type_as(x)

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# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
# This source code is licensed under the license found in the
# LICENSE file in the root directory of this source tree.
import time
from pathlib import Path
import torch
import torch.nn as nn
import torch.nn.functional as F
from tokenizer import get_tokenizer
try:
from GPTQ import GenericGPTQRunner, InputRecorder
from eval import get_task_dict, evaluate, lm_eval
except:
pass
from model import Transformer
##### Quantization Primitives ######
def dynamically_quantize_per_channel(x, quant_min, quant_max, target_dtype):
# assumes symmetric quantization
# assumes axis == 0
# assumes dense memory format
# TODO(future): relax ^ as needed
# default setup for affine quantization of activations
eps = torch.finfo(torch.float32).eps
# get min and max
min_val, max_val = torch.aminmax(x, dim=1)
# calculate scales and zero_points based on min and max
# reference: https://fburl.com/code/srbiybme
min_val_neg = torch.min(min_val, torch.zeros_like(min_val))
max_val_pos = torch.max(max_val, torch.zeros_like(max_val))
device = min_val_neg.device
# reference: https://fburl.com/code/4wll53rk
max_val_pos = torch.max(-min_val_neg, max_val_pos)
scales = max_val_pos / (float(quant_max - quant_min) / 2)
# ensure scales is the same dtype as the original tensor
scales = torch.clamp(scales, min=eps).to(x.dtype)
zero_points = torch.zeros(min_val_neg.size(), dtype=torch.int64, device=device)
# quantize based on qmin/qmax/scales/zp
# reference: https://www.internalfb.com/code/fbsource/[8edc275012b1]/fbcode/caffe2/torch/ao/quantization/fx/_decomposed.py?lines=63
x_div = x / scales.unsqueeze(-1)
x_round = torch.round(x_div)
x_zp = x_round + zero_points.unsqueeze(-1)
quant = torch.clamp(x_zp, quant_min, quant_max).to(target_dtype)
return quant, scales, zero_points
def get_group_qparams(w, n_bit=4, groupsize=128):
# needed for GPTQ with padding
if groupsize > w.shape[-1]:
groupsize = w.shape[-1]
assert groupsize > 1
assert w.shape[-1] % groupsize == 0
assert w.dim() == 2
to_quant = w.reshape(-1, groupsize)
assert torch.isnan(to_quant).sum() == 0
max_val = to_quant.amax(dim=1, keepdim=True)
min_val = to_quant.amin(dim=1, keepdim=True)
max_int = 2**n_bit - 1
scales = (max_val - min_val).clamp(min=1e-6) / max_int
zeros = min_val + scales * (2 ** (n_bit - 1))
return scales.to(torch.bfloat16).reshape(w.shape[0], -1), zeros.to(
torch.bfloat16
).reshape(w.shape[0], -1)
def pack_scales_and_zeros(scales, zeros):
assert scales.shape == zeros.shape
assert scales.dtype == torch.bfloat16
assert zeros.dtype == torch.bfloat16
return (
torch.cat(
[
scales.reshape(scales.size(0), scales.size(1), 1),
zeros.reshape(zeros.size(0), zeros.size(1), 1),
],
2,
)
.transpose(0, 1)
.contiguous()
)
def unpack_scales_and_zeros(scales_and_zeros):
assert len(scales_and_zeros.shape) == 3 and scales_and_zeros.shape[2] == 2
assert scales_and_zeros.dtype == torch.float
return torch.split(scales_and_zeros.transpose(0, 1), 1, 2)
def group_quantize_tensor_from_qparams(w, scales, zeros, n_bit=4, groupsize=128):
assert groupsize > 1
# needed for GPTQ single column quantize
if groupsize > w.shape[-1] and scales.shape[-1] == 1:
groupsize = w.shape[-1]
assert w.shape[-1] % groupsize == 0
assert w.dim() == 2
to_quant = w.reshape(-1, groupsize)
assert torch.isnan(to_quant).sum() == 0
scales = scales.reshape(-1, 1)
zeros = zeros.reshape(-1, 1)
min_val = zeros - scales * (2 ** (n_bit - 1))
max_int = 2**n_bit - 1
min_int = 0
w_int32 = (
to_quant.sub(min_val)
.div(scales)
.round()
.clamp_(min_int, max_int)
.to(torch.int32)
.reshape_as(w)
)
return w_int32
def group_quantize_tensor(w, n_bit=4, groupsize=128):
scales, zeros = get_group_qparams(w, n_bit, groupsize)
w_int32 = group_quantize_tensor_from_qparams(w, scales, zeros, n_bit, groupsize)
scales_and_zeros = pack_scales_and_zeros(scales, zeros)
return w_int32, scales_and_zeros
def group_dequantize_tensor_from_qparams(
w_int32, scales, zeros, n_bit=4, groupsize=128
):
assert groupsize > 1
# needed for GPTQ single column dequantize
if groupsize > w_int32.shape[-1] and scales.shape[-1] == 1:
groupsize = w_int32.shape[-1]
assert w_int32.shape[-1] % groupsize == 0
assert w_int32.dim() == 2
w_int32_grouped = w_int32.reshape(-1, groupsize)
scales = scales.reshape(-1, 1)
zeros = zeros.reshape(-1, 1)
w_dq = (
w_int32_grouped.sub(2 ** (n_bit - 1)).mul(scales).add(zeros).reshape_as(w_int32)
)
return w_dq
def group_dequantize_tensor(w_int32, scales_and_zeros, n_bit=4, groupsize=128):
scales, zeros = unpack_scales_and_zeros(scales_and_zeros)
return group_dequantize_tensor_from_qparams(
w_int32, scales, zeros, n_bit, groupsize
)
class QuantHandler:
def __init__(self, mod):
self.mod = mod
def create_quantized_state_dict(self) -> "StateDict":
pass
def convert_for_runtime(self) -> "nn.Module":
pass
class GPTQQuantHandler(QuantHandler):
"""
This class implements a GPTQ QuantHandler that can be used to apply GPTQ to a model in concert with the GenericGPTQRunner class.
Unlike the base QuantHandler class, the user does not need to implement the create_quantized_state_dict, instead they have to reimplement
__init__ such that it defines the functions for the quantization mode. User is expected to reimplement convert_for_runtime.
The following functions (which must be defined in __init__) are used to define the quantization mode for both GPTQ and
create_quantized_state_dict. Here is a description of each function.
get_qparams_func:
A function that calculates the quantization qparams for an input tensor.
Args:
weight: A 2d weight tensor with non-integer dtype.
Returns:
qparams: it can have any format but will need to be handled by the other defined functions below.
quantize_func:
A function that applies quantization to an input tensor. It should be noted
that this function needs to be able to handle quantizing the entire weight tensor, a single group,
or a single column.
Args:
weight: A 2d weight tensor with non-integer dtype.
qparams: the output from get_qparams_func
Returns:
quantized_weight: A 2d quantized weight tensor (generally with an integer dtype)
dequantize_func:
A function that dequantizes an input quantized weight tensor. It should be noted
that this function needs to be able to handle dequantizing the entire weight tensor, a single group,
or a single column.
Args:
quantized_weight: A 2d quantized weight tensor (generally with an integer dtype)
qparams: the output from get_qparams_func
Returns:
weight: A 2d weight tensor with non-integer dtype.
combine_qparams_list_func:
A function that combines several qparams into one qparam.
Args:
qparams_list: a list of qparams objects, each obtained by calling get_qparams_func
on a single group from a weight tensor
Returns:
qparams: an object of the same format as the qparams above.
skip_layer_func:
A function that determines which linear layers should be skipped during GPTQ
Args:
weight: A 2d weight tensor with non-integer dtype.
Returns:
skip: boolean indicating whether layer should be skipped
make_names_and_values_dict_func:
A function that prepares the qparams and quantized_weight and creates a dictionary indicating how they
should be inserted into the state_dict. Generally any packing of the weight and qparams should be done here.
Args:
quantized_weight: A 2d quantized weight tensor (generally with an integer dtype)
qparams: the output from get_qparams_func
Returns:
names_and_values_dict: a dictionary mapping the name of the parameters of the quantized module to the
corresponding quantized weights and qparams.
"""
def __init__(self):
assert self.mod is not None
assert self.get_qparams_func is not None
assert self.quantize_func is not None
assert self.dequantize_func is not None
assert self.combine_qparams_list_func is not None
assert self.make_names_and_values_dict_func is not None
@staticmethod
def get_inputs(model, tokenizer, calibration_tasks, calibration_limit, calibration_seq_length, pad_calibration_inputs) -> "MultiInput":
input_recorder = InputRecorder(
model,
tokenizer,
calibration_seq_length,
pad_calibration_inputs,
)
try:
lm_eval.tasks.initialize_tasks()
except:
pass
task_dict = get_task_dict(calibration_tasks)
print("Obtaining GPTQ calibration inputs on: ", calibration_tasks)
evaluate(
input_recorder,
task_dict,
limit=calibration_limit,
)
inputs = input_recorder.get_recorded_inputs()
assert inputs is not None, (
f"No inputs were collected, use a task other than {calibration_tasks}, "+
f"use option pad_calibration_inputs, or decrease calibration_sequence_length (currently "+
f"{calibration_seq_length})"
)
print(f"Obtained {len(inputs[0].values)} calibration samples")
return inputs
@torch.no_grad()
def create_quantized_state_dict(
self,
tokenizer,
blocksize,
percdamp,
groupsize,
calibration_tasks,
calibration_limit,
calibration_seq_length,
pad_calibration_inputs,
) -> "StateDict":
inputs = GPTQQuantHandler.get_inputs(self.mod, tokenizer, calibration_tasks, calibration_limit, calibration_seq_length, pad_calibration_inputs)
print("Tracing model for GPTQ")
GPTQ_runner = GenericGPTQRunner(
self.mod,
inputs,
blocksize,
percdamp,
groupsize,
).configure_quantization_mode(
self.get_qparams_func,
self.quantize_func,
self.dequantize_func,
self.combine_qparams_list_func,
self.make_names_and_values_dict_func,
self.skip_layer_func
)
print("Applying GPTQ to weights")
GPTQ_runner.run()
return GPTQ_runner.get_quantized_state_dict()
def convert_for_runtime(self) -> "nn.Module":
pass
##### Weight-only int8 per-channel quantized code ######
def replace_linear_weight_only_int8_per_channel(module):
for name, child in module.named_children():
if isinstance(child, nn.Linear):
setattr(module, name, WeightOnlyInt8Linear(child.in_features, child.out_features))
else:
replace_linear_weight_only_int8_per_channel(child)
class WeightOnlyInt8QuantHandler:
def __init__(self, mod):
self.mod = mod
@torch.no_grad()
def create_quantized_state_dict(self):
cur_state_dict = self.mod.state_dict()
for fqn, mod in self.mod.named_modules():
if isinstance(mod, torch.nn.Linear):
int8_weight, scales, _ = dynamically_quantize_per_channel(mod.weight.float(), -128, 127, torch.int8)
cur_state_dict[f"{fqn}.weight"] = int8_weight
cur_state_dict[f"{fqn}.scales"] = scales.to(mod.weight.dtype)
return cur_state_dict
def convert_for_runtime(self):
replace_linear_weight_only_int8_per_channel(self.mod)
return self.mod
class WeightOnlyInt8Linear(torch.nn.Module):
__constants__ = ['in_features', 'out_features']
in_features: int
out_features: int
weight: torch.Tensor
def __init__(self, in_features: int, out_features: int, bias: bool = True,
device=None, dtype=None) -> None:
factory_kwargs = {'device': device, 'dtype': dtype}
super().__init__()
self.in_features = in_features
self.out_features = out_features
self.register_buffer("weight", torch.empty((out_features, in_features), dtype=torch.int8))
self.register_buffer("scales", torch.ones(out_features, dtype=torch.bfloat16))
def forward(self, input: torch.Tensor) -> torch.Tensor:
return F.linear(input, self.weight.to(dtype=input.dtype)) * self.scales
##### weight only int4 per channel groupwise quantized code ######
def prepare_int4_weight_and_scales_and_zeros(weight_bf16, groupsize, inner_k_tiles):
weight_int32, scales_and_zeros = group_quantize_tensor(
weight_bf16, n_bit=4, groupsize=groupsize
)
weight_int4pack = torch.ops.aten._convert_weight_to_int4pack(weight_int32, inner_k_tiles)
return weight_int4pack, scales_and_zeros
def linear_forward_int4(x, weight_int4pack, scales_and_zeros, out_features, groupsize):
origin_x_size = x.size()
x = x.reshape(-1, origin_x_size[-1])
c = torch.ops.aten._weight_int4pack_mm(x, weight_int4pack, groupsize, scales_and_zeros)
new_shape = origin_x_size[:-1] + (out_features,)
c = c.reshape(new_shape)
return c
def _check_linear_int4_k(k, groupsize = 1, inner_k_tiles = 1):
return k % groupsize == 0 and k % (inner_k_tiles * 16) == 0
def replace_linear_int4(module, groupsize, inner_k_tiles, padding):
for name, child in module.named_children():
if isinstance(child, nn.Linear):
if _check_linear_int4_k(child.in_features, groupsize, inner_k_tiles):
setattr(module, name, WeightOnlyInt4Linear(
child.in_features, child.out_features, bias=False,
groupsize=groupsize, inner_k_tiles=inner_k_tiles, padding=False,
))
elif padding:
setattr(module, name, WeightOnlyInt4Linear(
child.in_features, child.out_features, bias=False,
groupsize=groupsize, inner_k_tiles=inner_k_tiles, padding=True,
))
else:
replace_linear_int4(child, groupsize, inner_k_tiles, padding)
class WeightOnlyInt4QuantHandler:
def __init__(self, mod, groupsize=128, inner_k_tiles=8, padding=True):
self.mod = mod
self.groupsize = groupsize
self.inner_k_tiles = inner_k_tiles
self.padding = padding
assert groupsize in [32, 64, 128, 256]
assert inner_k_tiles in [2, 4, 8]
@torch.no_grad()
def create_quantized_state_dict(self, use_cuda = True):
if use_cuda:
device="cuda"
else:
device="cpu"
cur_state_dict = self.mod.state_dict()
for fqn, mod in self.mod.named_modules():
if isinstance(mod, torch.nn.Linear):
assert not mod.bias
out_features = mod.out_features
in_features = mod.in_features
assert out_features % 8 == 0, "require out_features % 8 == 0"
print(f"linear: {fqn}, in={in_features}, out={out_features}")
weight = mod.weight.data
if not _check_linear_int4_k(in_features, self.groupsize, self.inner_k_tiles):
if self.padding:
from model import find_multiple
import torch.nn.functional as F
print(f"warning: {fqn} is padded to satisfy in_features % 1024 == 0")
padded_in_features = find_multiple(in_features, 1024)
weight = F.pad(weight, pad=(0, padded_in_features - in_features))
else:
print(f"warning: {fqn} is skipped, int4 requires that in_features is 32, 64, or is divisible by 1024, " +
"and that groupsize and inner_k_tiles*16 evenly divide into it")
continue
weight_int4pack, scales_and_zeros = prepare_int4_weight_and_scales_and_zeros(
weight.to(torch.bfloat16).to(device=device), self.groupsize, self.inner_k_tiles
)
cur_state_dict[f"{fqn}.weight"] = weight_int4pack.to('cpu')
cur_state_dict[f"{fqn}.scales_and_zeros"] = scales_and_zeros.to('cpu')
return cur_state_dict
def convert_for_runtime(self):
replace_linear_int4(self.mod, self.groupsize, self.inner_k_tiles, self.padding)
return self.mod
class WeightOnlyInt4GPTQQuantHandler(GPTQQuantHandler):
def __init__(self, mod, groupsize=128, inner_k_tiles=8, padding=True):
from model import find_multiple
self.mod = mod
self.groupsize = groupsize
self.inner_k_tiles = inner_k_tiles
self.padding = padding
self.get_qparams_func = lambda w: get_group_qparams(w, 4, groupsize)
self.quantize_func = lambda w, qparams: \
group_quantize_tensor_from_qparams(w, qparams[0], qparams[1], 4, groupsize)
self.dequantize_func = lambda q, qparams: \
group_dequantize_tensor_from_qparams(q, qparams[0], qparams[1], 4, groupsize).float()
self.combine_qparams_list_func = lambda qparams_list: \
[torch.cat(x, dim=1) for x in zip(*qparams_list)]
# skip unless padding=True or its correctly sized
self.skip_layer_func = lambda linear_weight: not (
_check_linear_int4_k(linear_weight.shape[-1], groupsize, inner_k_tiles) or padding
)
# we need to do the padding here, both for q and the qparams if necessary
def make_names_and_values_dict_func(q, qparams):
k = q.shape[1]
new_k = find_multiple(k, 1024)
# how much we need to pad the weight
delta_k = new_k - q.shape[1]
final_q = torch.ops.aten._convert_weight_to_int4pack(F.pad(q, pad=(0, delta_k)), inner_k_tiles)
scales_and_zeros = pack_scales_and_zeros(*qparams)
# how many new groups we need for padded weight
delta_groups = new_k // groupsize - scales_and_zeros.shape[0]
final_s_and_z = F.pad(scales_and_zeros, pad=(0,0,0,0,0, delta_groups), value=1)
return {"weight": final_q, "scales_and_zeros": final_s_and_z}
self.make_names_and_values_dict_func = make_names_and_values_dict_func
super().__init__()
def convert_for_runtime(self):
replace_linear_int4(self.mod, self.groupsize, self.inner_k_tiles, self.padding)
return self.mod
class WeightOnlyInt4Linear(torch.nn.Module):
__constants__ = ['in_features', 'out_features']
in_features: int
out_features: int
weight: torch.Tensor
def __init__(
self, in_features: int, out_features: int,
bias=True, device=None, dtype=None, groupsize: int = 128, inner_k_tiles: int = 8, padding: bool = True,
) -> None:
super().__init__()
self.padding = padding
if padding:
from model import find_multiple
self.origin_in_features = in_features
in_features = find_multiple(in_features, 1024)
self.in_features = in_features
self.out_features = out_features
assert not bias, "require bias=False"
self.groupsize = groupsize
self.inner_k_tiles = inner_k_tiles
assert out_features % 8 == 0, "require out_features % 8 == 0"
assert in_features % (inner_k_tiles * 16) == 0, "require in_features % (innerKTiles * 16) == 0"
self.register_buffer(
"weight",
torch.empty((out_features // 8, in_features // (inner_k_tiles * 16), 32, inner_k_tiles // 2), dtype=torch.int32)
)
self.register_buffer(
"scales_and_zeros",
torch.empty((in_features // groupsize, out_features, 2), dtype=torch.bfloat16)
)
def forward(self, input: torch.Tensor) -> torch.Tensor:
input = input.to(torch.bfloat16)
if self.padding:
import torch.nn.functional as F
input = F.pad(input, pad=(0, self.in_features - self.origin_in_features))
return linear_forward_int4(
input,
self.weight, self.scales_and_zeros, self.out_features, self.groupsize
)
def quantize(
checkpoint_path: Path = Path("checkpoints/meta-llama/Llama-2-7b-chat-hf/model.pth"),
mode: str = 'int8',
# following arguments only available when setting int4 quantization.
groupsize: int = 128,
# following arguments only used for GPTQ
calibration_tasks: list = ["hellaswag"],
calibration_limit: int = 1000,
calibration_seq_length: int = 100,
pad_calibration_inputs: bool = False,
percdamp: float = .01,
blocksize: int = 128,
label: str = '',
) -> None:
assert checkpoint_path.is_file(), checkpoint_path
device = 'cpu'
precision = torch.bfloat16
print("Loading model ...")
t0 = time.time()
with torch.device('meta'):
model = Transformer.from_name(checkpoint_path.parent.name)
checkpoint = torch.load(str(checkpoint_path), mmap=True, weights_only=True)
model.load_state_dict(checkpoint, assign=True)
model = model.to(dtype=precision, device=device)
if mode == 'int8':
print("Quantizing model weights for int8 weight-only symmetric per-channel quantization")
quant_handler = WeightOnlyInt8QuantHandler(model)
quantized_state_dict = quant_handler.create_quantized_state_dict()
dir_name = checkpoint_path.parent
base_name = checkpoint_path.name
new_base_name = base_name.replace('.pth', f'{label}int8.pth')
elif mode == 'int4':
print("Quantizing model weights for int4 weight-only affine per-channel groupwise quantization")
quant_handler = WeightOnlyInt4QuantHandler(model, groupsize)
quantized_state_dict = quant_handler.create_quantized_state_dict()
dir_name = checkpoint_path.parent
base_name = checkpoint_path.name
new_base_name = base_name.replace('.pth', f"{label}int4.g{groupsize}.pth")
elif mode == 'int4-gptq':
print("Quantizing model weights for int4 weight-only affine per-channel groupwise quantization using GPTQ...")
quant_handler = WeightOnlyInt4GPTQQuantHandler(model, groupsize)
tokenizer_path = checkpoint_path.parent / "tokenizer.model"
assert tokenizer_path.is_file(), str(tokenizer_path)
tokenizer = get_tokenizer(tokenizer_path, checkpoint_path)
quantized_state_dict = quant_handler.create_quantized_state_dict(
tokenizer,
blocksize,
percdamp,
groupsize,
calibration_tasks,
calibration_limit,
calibration_seq_length,
pad_calibration_inputs
)
dir_name = checkpoint_path.parent
base_name = checkpoint_path.name
new_base_name = base_name.replace('.pth', f"{label}int4-gptq.g{groupsize}.pth")
else:
raise ValueError(f"Invalid quantization mode {mode} needs to be one of [int8, int4, int4-gpptq]")
quantize_path = dir_name / new_base_name
print(f"Writing quantized weights to {quantize_path}")
quantize_path.unlink(missing_ok=True) # remove existing file if one already there
torch.save(quantized_state_dict, quantize_path)
print(f"Quantization complete took {time.time() - t0:.02f} seconds")
return
if __name__ == '__main__':
import argparse
parser = argparse.ArgumentParser(description='Quantize a model.')
parser.add_argument('--checkpoint_path', type=Path, default=Path("checkpoints/meta-llama/Llama-2-7b-chat-hf/model.pth"), help='Path to the model checkpoint to be quantized.')
parser.add_argument('--mode', '-q', type=str, default='int8', choices=['int8', 'int4', 'int4-gptq'], help='type of quantization to perform')
parser.add_argument('--groupsize', type=int, default=32, help='Group size for int4 quantization.')
parser.add_argument('--calibration_tasks', type=str, nargs='+', default=['wikitext'], help='tasks to do gptq calibration on, if doing gptq')
parser.add_argument('--calibration_limit', type=int, default=1000, help='number of samples to use for gptq calibration')
parser.add_argument('--calibration_seq_length', type=int, default=100, help='length of sequences to use for gptq calibration')
parser.add_argument('--pad_calibration_inputs', type=bool, default=False, help='pads sequences shorter than calibration_seq_length to that length, yielding more calibration inputs but running much slower')
parser.add_argument('--percdamp', type=float, default=.01, help='gptq percentage dampening')
parser.add_argument('--blocksize', type=int, default=128, help='blocksize for gptq')
parser.add_argument('--label', type=str, default='_', help='label to add to output filename')
args = parser.parse_args()
quantize(args.checkpoint_path, args.mode, args.groupsize, args.calibration_tasks, args.calibration_limit, args.calibration_seq_length, args.pad_calibration_inputs, args.percdamp, args.blocksize, args.label)