GPTQv2 support

GPTQv2 support.
1. Adds dependency on `triton`
2. Refactors autograd_4bit to include both GPTQv1 and GPTQv2
3. Introduces new environment variable GPTQ_VERSION to select autograd_4bit version
4. Fixes triton kernels
5. Matrix multiplications are in fp16
This commit is contained in:
Andrey Glushenkov 2023-04-06 02:29:36 +03:00 committed by GitHub
parent 86387a0a35
commit f20570343f
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8 changed files with 618 additions and 1 deletions

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@ -95,5 +95,6 @@ class Finetune4bConfig:
f"{self.warmup_steps=}\n{self.save_steps=}\n{self.save_total_limit=}\n" +\
f"{self.logging_steps=}\n" +\
f"{self.checkpoint=}\n{self.skip=}\n" +\
f"{self.world_size=}\n{self.ddp=}\n{self.device_map=}"
f"{self.world_size=}\n{self.ddp=}\n{self.device_map=}\n" +\
f"{self.groupsize=}\n"
return s.replace("self.", "")

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@ -34,10 +34,20 @@ pip install -r requirements.txt
~The same finetune script from https://github.com/tloen/alpaca-lora can be used.~<br>
After installation, this script can be used:
GPTQv1:
```
python finetune.py
```
or
```
GPTQ_VERSION=1 python finetune.py
```
GPTQv2:
```
GPTQ_VERSION=2 python finetune.py
```
# Inference

21
autograd_4bit/__init__.py Normal file
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@ -0,0 +1,21 @@
import os
from colorama import init, Fore, Back, Style
init(autoreset=True)
try:
GPTQ_VERSION = int(os.environ["GPTQ_VERSION"])
except:
print(Style.BRIGHT + Fore.YELLOW + "GPTQ_VERSION environment not provided. Fallback to GPTQv1")
GPTQ_VERSION = 1 # Fallback version
loader = None
if GPTQ_VERSION == 1:
from .autograd_4bit_v1 import Autograd4bitQuantLinear, load_llama_model_4bit_low_ram
print(Style.BRIGHT + Fore.GREEN + "GPTQv1 set")
elif GPTQ_VERSION == 2:
from .autograd_4bit_v2 import Autograd4bitQuantLinear, load_llama_model_4bit_low_ram
print(Style.BRIGHT + Fore.GREEN + "GPTQv2 set")
else:
raise ValueError("GPTQ_VERSION not set or invalid")

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@ -0,0 +1,208 @@
import matmul_utils_4bit as mm4b
import torch
import torch.nn as nn
import time
class AutogradMatmul4bit(torch.autograd.Function):
@staticmethod
def forward(ctx, x, qweight, scales, zeros, groupsize=-1):
ctx.save_for_backward(qweight, scales, zeros)
ctx.groupsize = groupsize
if groupsize == -1:
output = mm4b._matmul4bit_v1_recons(x, qweight, scales, zeros)
else:
output = mm4b._matmul4bit_v2_recons(x, qweight, scales, zeros, groupsize)
output = output.clone()
return output
@staticmethod
def backward(ctx, grad_output):
qweight, scales, zeros = ctx.saved_tensors
groupsize = ctx.groupsize
if groupsize == -1:
grad = mm4b._matmul4bit_v1_recons(grad_output, qweight, scales, zeros, transpose=True)
else:
grad = mm4b._matmul4bit_v2_recons(grad_output, qweight, scales, zeros, groupsize=groupsize, transpose=True)
return grad, None, None, None, None
# Assumes layer is perfectly divisible into 256 * 256 blocks
class Autograd4bitQuantLinear(nn.Module):
def __init__(self, in_features, out_features, groupsize=None):
super().__init__()
bits = 4
self.in_features = in_features
self.out_features = out_features
self.bits = bits
self.register_buffer('zeros', torch.empty((out_features, 1)))
self.register_buffer('scales', torch.empty((out_features, 1)))
self.bias = nn.Parameter(torch.empty(out_features))
self.register_buffer(
'qweight', torch.empty((in_features // 256 * (bits * 8), out_features), dtype=torch.int)
)
def forward(self, x):
if torch.is_grad_enabled():
out = AutogradMatmul4bit.apply(x, self.qweight, self.scales,
self.qzeros if self.groupsize != -1 else self.zeros, self.groupsize)
out.add_(self.bias)
else:
out = mm4b.matmul4bit(x, self.qweight, self.scales,
self.qzeros if self.groupsize != -1 else self.zeros, self.groupsize)
out.add_(self.bias)
return out
def make_quant_for_4bit_autograd(module, names, name='', groupsize=-1):
if isinstance(module, Autograd4bitQuantLinear):
return
for attr in dir(module):
tmp = getattr(module, attr)
name1 = name + '.' + attr if name != '' else attr
if name1 in names:
setattr(
module, attr, Autograd4bitQuantLinear(tmp.in_features, tmp.out_features, groupsize=groupsize)
)
for name1, child in module.named_children():
make_quant_for_4bit_autograd(child, names, name + '.' + name1 if name != '' else name1, groupsize=groupsize)
def model_to_half(model):
model.half()
for n, m in model.named_modules():
if isinstance(m, Autograd4bitQuantLinear):
m.zeros = m.zeros.half()
m.scales = m.scales.half()
m.bias = m.bias.half()
print('Converted as Half.')
def model_to_float(model):
model.float()
for n, m in model.named_modules():
if isinstance(m, Autograd4bitQuantLinear):
m.zeros = m.zeros.float()
m.scales = m.scales.float()
m.bias = m.bias.float()
print('Converted as Float.')
def find_layers(module, layers=[nn.Conv2d, nn.Linear], name=''):
if type(module) in layers:
return {name: module}
res = {}
for name1, child in module.named_children():
res.update(find_layers(
child, layers=layers, name=name + '.' + name1 if name != '' else name1
))
return res
def load_llama_model_4bit_low_ram(config_path, model_path, groupsize=-1, half=False, device_map="auto", seqlen=2048):
import accelerate
from transformers import LlamaConfig, LlamaForCausalLM, LlamaTokenizer
print("Loading Model ...")
t0 = time.time()
with accelerate.init_empty_weights():
config = LlamaConfig.from_pretrained(config_path)
model = LlamaForCausalLM(config)
model = model.eval()
layers = find_layers(model)
for name in ['lm_head']:
if name in layers:
del layers[name]
make_quant_for_4bit_autograd(model, layers, groupsize=groupsize)
model = accelerate.load_checkpoint_and_dispatch(
model=model,
checkpoint=model_path,
device_map=device_map,
no_split_module_classes=["LlamaDecoderLayer"]
)
model.seqlen = seqlen
if half:
model_to_half(model)
tokenizer = LlamaTokenizer.from_pretrained(config_path)
tokenizer.truncation_side = 'left'
print(f"Loaded the model in {(time.time()-t0):.2f} seconds.")
return model, tokenizer
def load_llama_model_4bit_low_ram_and_offload_to_cpu(config_path, model_path, lora_path=None, groupsize=-1, seqlen=2048, max_memory=None):
import accelerate
from transformers import LlamaConfig, LlamaForCausalLM, LlamaTokenizer
if max_memory is None:
max_memory = {0: '24Gib', 'cpu': '48Gib'}
print("Loading Model ...")
t0 = time.time()
with accelerate.init_empty_weights():
config = LlamaConfig.from_pretrained(config_path)
model = LlamaForCausalLM(config)
model = model.eval()
layers = find_layers(model)
for name in ['lm_head']:
if name in layers:
del layers[name]
make_quant_for_4bit_autograd(model, layers, groupsize=groupsize)
accelerate.load_checkpoint_in_model(model, checkpoint=model_path, device_map={'': 'cpu'})
# rotary_emb fix
for n, m in model.named_modules():
if 'rotary_emb' in n:
cos_cached = m.cos_cached.clone().cpu()
sin_cached = m.sin_cached.clone().cpu()
break
if lora_path is not None:
from peft import PeftModel
from peft.tuners.lora import Linear4bitLt
model = PeftModel.from_pretrained(model, lora_path, device_map={'': 'cpu'}, torch_dtype=torch.float32)
print('{} Lora Applied.'.format(lora_path))
model.seqlen = seqlen
print('Apply half ...')
for n, m in model.named_modules():
if isinstance(m, Autograd4bitQuantLinear) or ((lora_path is not None) and isinstance(m, Linear4bitLt)):
m.zeros = m.zeros.half()
m.scales = m.scales.half()
m.bias = m.bias.half()
print('Dispatching model ...')
device_map = accelerate.infer_auto_device_map(model, max_memory=max_memory, no_split_module_classes=["LlamaDecoderLayer"])
model = accelerate.dispatch_model(model, device_map=device_map, offload_buffers=True, main_device=0)
torch.cuda.empty_cache()
print('Total {:.2f} Gib VRAM used.'.format(torch.cuda.memory_allocated() / 1024 / 1024))
# rotary_emb fix
for n, m in model.named_modules():
if 'rotary_emb' in n:
if getattr(m, '_hf_hook', None):
if isinstance(m._hf_hook, accelerate.hooks.SequentialHook):
hooks = m._hf_hook.hooks
else:
hooks = [m._hf_hook]
for hook in hooks:
if hook.offload:
if n + '.sin_cached' not in hook.weights_map.dataset.state_dict.keys():
hook.weights_map.dataset.state_dict[n + '.sin_cached'] = sin_cached.clone().cpu()
hook.weights_map.dataset.state_dict[n + '.cos_cached'] = cos_cached.clone().cpu()
tokenizer = LlamaTokenizer.from_pretrained(config_path)
tokenizer.truncation_side = 'left'
print(f"Loaded the model in {(time.time()-t0):.2f} seconds.")
return model, tokenizer

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@ -0,0 +1,221 @@
from colorama import init, Fore, Back, Style
import torch
import torch.nn as nn
import time
import math
import triton
from triton_utils import matmul_248_kernel, trans_matmul_248_kernel
class AutogradMatmul4bit(torch.autograd.Function):
@staticmethod
def forward(ctx, input, qweight, scales, qzeros, g_idx, bits, maxq):
output = torch.empty((input.shape[0], qweight.shape[1]), device='cuda', dtype=torch.float16)
grid = lambda META: (triton.cdiv(input.shape[0], META['BLOCK_SIZE_M']) * triton.cdiv(qweight.shape[1], META['BLOCK_SIZE_N']),)
matmul_248_kernel[grid](input, qweight, output,
scales, qzeros, g_idx,
input.shape[0], qweight.shape[1], input.shape[1], bits, maxq,
input.stride(0), input.stride(1),
qweight.stride(0), qweight.stride(1),
output.stride(0), output.stride(1),
scales.stride(0), qzeros.stride(0))
ctx.save_for_backward(qweight, scales, qzeros, g_idx)
ctx.input_shape, ctx.bits,ctx.maxq = input.shape,bits, maxq
return output
@staticmethod
def backward(ctx, grad_output):
input_shape, bits, maxq = ctx.input_shape, ctx.bits, ctx.maxq
qweight, scales, qzeros, g_idx = ctx.saved_tensors
grade_input = None
if ctx.needs_input_grad[0]:
grade_input = torch.empty((input_shape[0], input_shape[1]), device='cuda', dtype=torch.float32)
grid = lambda META: (triton.cdiv(input_shape[0], META['BLOCK_SIZE_M']) * triton.cdiv(input_shape[1], META['BLOCK_SIZE_K']),)
trans_matmul_248_kernel[grid](grad_output, qweight, grade_input,
scales, qzeros, g_idx,
input_shape[0], qweight.shape[1], input_shape[1], bits, maxq,
grad_output.stride(0), grad_output.stride(1),
qweight.stride(0), qweight.stride(1),
grade_input.stride(0), grade_input.stride(1),
scales.stride(0), qzeros.stride(0))
return grade_input, None, None, None, None, None, None
class Autograd4bitQuantLinear(nn.Module):
def __init__(self, in_features, out_features, groupsize, bias=True):
super().__init__()
self.in_features = in_features
self.out_features = out_features
self.bits = 4 # Hardcoded 4-bits quantizations
self.maxq = 2 ** self.bits - 1
self.groupsize = groupsize if groupsize != -1 else in_features
self.register_buffer('qweight', torch.zeros((in_features // 32 * self.bits, out_features), dtype=torch.int32))
self.register_buffer('qzeros', torch.zeros((math.ceil(in_features / self.groupsize), out_features // 32 * self.bits), dtype=torch.int32))
self.register_buffer('scales', torch.zeros((math.ceil(in_features / self.groupsize), out_features), dtype=torch.float16))
self.register_buffer('g_idx', torch.tensor([i // self.groupsize for i in range(in_features)], dtype = torch.int32))
if bias:
self.register_buffer('bias', torch.zeros(out_features,dtype=torch.float16))
else:
self.bias = None
def forward(self, x):
out_shape = x.shape[:-1] + (self.out_features, )
out = AutogradMatmul4bit.apply(x.reshape(-1,x.shape[-1]), self.qweight, self.scales,
self.qzeros, self.g_idx, self.bits, self.maxq)
out = out + self.bias if self.bias is not None else out
return out.reshape(out_shape)
def make_quant_for_4bit_autograd(module, names, name='', groupsize=-1):
if isinstance(module, Autograd4bitQuantLinear):
return
for attr in dir(module):
tmp = getattr(module, attr)
name1 = name + '.' + attr if name != '' else attr
if name1 in names:
setattr(
module, attr, Autograd4bitQuantLinear(tmp.in_features, tmp.out_features, groupsize=groupsize)
)
for name1, child in module.named_children():
make_quant_for_4bit_autograd(child, names, name + '.' + name1 if name != '' else name1, groupsize=groupsize)
def model_to_half(model):
model.half()
for n, m in model.named_modules():
if isinstance(m, Autograd4bitQuantLinear):
m.qzeros = m.qzeros.half()
m.scales = m.scales.half()
m.bias = m.bias.half()
print(Style.BRIGHT + Fore.YELLOW + 'Converted as Half.')
def model_to_float(model):
model.float()
for n, m in model.named_modules():
if isinstance(m, Autograd4bitQuantLinear):
m.qzeros = m.qzeros.float()
m.scales = m.scales.float()
m.bias = m.bias.float()
print(Style.BRIGHT + Fore.YELLOW + 'Converted as Float.')
def find_layers(module, layers=[nn.Conv2d, nn.Linear], name=''):
if type(module) in layers:
return {name: module}
res = {}
for name1, child in module.named_children():
res.update(find_layers(
child, layers=layers, name=name + '.' + name1 if name != '' else name1
))
return res
def load_llama_model_4bit_low_ram(config_path, model_path, groupsize=-1, half=False, device_map="auto", seqlen=2048):
import accelerate
from transformers import LlamaConfig, LlamaForCausalLM, LlamaTokenizer
print(Style.BRIGHT + Fore.CYAN + "Loading Model ...")
t0 = time.time()
with accelerate.init_empty_weights():
config = LlamaConfig.from_pretrained(config_path)
model = LlamaForCausalLM(config)
model = model.eval()
layers = find_layers(model)
for name in ['lm_head']:
if name in layers:
del layers[name]
make_quant_for_4bit_autograd(model, layers, groupsize=groupsize)
model = accelerate.load_checkpoint_and_dispatch(
model=model,
checkpoint=model_path,
device_map=device_map,
no_split_module_classes=["LlamaDecoderLayer"]
)
model.seqlen = seqlen
if half:
model_to_half(model)
tokenizer = LlamaTokenizer.from_pretrained(config_path)
tokenizer.truncation_side = 'left'
print(Style.BRIGHT + Fore.GREEN + f"Loaded the model in {(time.time()-t0):.2f} seconds.")
return model, tokenizer
def load_llama_model_4bit_low_ram_and_offload_to_cpu(config_path, model_path, lora_path=None, groupsize=-1, seqlen=2048, max_memory=None):
import accelerate
from transformers import LlamaConfig, LlamaForCausalLM, LlamaTokenizer
if max_memory is None:
max_memory = {0: '24Gib', 'cpu': '48Gib'}
print(Style.BRIGHT + Fore.CYAN + "Loading Model ...")
t0 = time.time()
with accelerate.init_empty_weights():
config = LlamaConfig.from_pretrained(config_path)
model = LlamaForCausalLM(config)
model = model.eval()
layers = find_layers(model)
for name in ['lm_head']:
if name in layers:
del layers[name]
make_quant_for_4bit_autograd(model, layers, groupsize=groupsize)
accelerate.load_checkpoint_in_model(model, checkpoint=model_path, device_map={'': 'cpu'})
# rotary_emb fix
for n, m in model.named_modules():
if 'rotary_emb' in n:
cos_cached = m.cos_cached.clone().cpu()
sin_cached = m.sin_cached.clone().cpu()
break
if lora_path is not None:
from peft import PeftModel
from peft.tuners.lora import Linear4bitLt
model = PeftModel.from_pretrained(model, lora_path, device_map={'': 'cpu'}, torch_dtype=torch.float32)
print(Style.BRIGHT + Fore.GREEN + '{} Lora Applied.'.format(lora_path))
model.seqlen = seqlen
print('Apply half ...')
for n, m in model.named_modules():
if isinstance(m, Autograd4bitQuantLinear) or ((lora_path is not None) and isinstance(m, Linear4bitLt)):
m.qzeros = m.qzeros.half()
m.scales = m.scales.half()
m.bias = m.bias.half()
print('Dispatching model ...')
device_map = accelerate.infer_auto_device_map(model, max_memory=max_memory, no_split_module_classes=["LlamaDecoderLayer"])
model = accelerate.dispatch_model(model, device_map=device_map, offload_buffers=True, main_device=0)
torch.cuda.empty_cache()
print(Style.BRIGHT + Fore.YELLOW + 'Total {:.2f} Gib VRAM used.'.format(torch.cuda.memory_allocated() / 1024 / 1024))
# rotary_emb fix
for n, m in model.named_modules():
if 'rotary_emb' in n:
if getattr(m, '_hf_hook', None):
if isinstance(m._hf_hook, accelerate.hooks.SequentialHook):
hooks = m._hf_hook.hooks
else:
hooks = [m._hf_hook]
for hook in hooks:
if hook.offload:
if n + '.sin_cached' not in hook.weights_map.dataset.state_dict.keys():
hook.weights_map.dataset.state_dict[n + '.sin_cached'] = sin_cached.clone().cpu()
hook.weights_map.dataset.state_dict[n + '.cos_cached'] = cos_cached.clone().cpu()
tokenizer = LlamaTokenizer.from_pretrained(config_path)
tokenizer.truncation_side = 'left'
print(Style.BRIGHT + Fore.GREEN + f"Loaded the model in {(time.time()-t0):.2f} seconds.")
return model, tokenizer

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@ -109,6 +109,7 @@ if not ft_config.skip:
per_device_train_batch_size=ft_config.mbatch_size,
gradient_accumulation_steps=ft_config.gradient_accumulation_steps,
warmup_steps=ft_config.warmup_steps,
optim="adamw_torch",
num_train_epochs=ft_config.epochs,
learning_rate=ft_config.lr,
fp16=True,

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@ -4,6 +4,7 @@ bitsandbytes
datasets
sentencepiece
safetensors
triton
git+https://github.com/huggingface/transformers.git
git+https://github.com/sterlind/GPTQ-for-LLaMa.git@lora_4bit
git+https://github.com/sterlind/peft.git

154
triton_test.py Normal file
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@ -0,0 +1,154 @@
import torch
import triton
import triton.language as tl
# %
# :code:`triton.jit`'ed functions can be auto-tuned by using the `triton.autotune`
# decorator, which consumes:
# - A list of :code:`triton.Config` objects that define different configurations of
# meta-parameters (e.g., BLOCK_SIZE_M) and compilation options (e.g., num_warps) to try
# - An autotuning *key* whose change in values will trigger evaluation of all the
# provided configs
@triton.autotune(
configs=[
triton.Config({'BLOCK_SIZE_M': 128, 'BLOCK_SIZE_N': 256, 'BLOCK_SIZE_K': 32, 'GROUP_SIZE_M': 8}, num_stages=3, num_warps=8),
triton.Config({'BLOCK_SIZE_M': 256, 'BLOCK_SIZE_N': 128, 'BLOCK_SIZE_K': 32, 'GROUP_SIZE_M': 8}, num_stages=3, num_warps=8),
triton.Config({'BLOCK_SIZE_M': 256, 'BLOCK_SIZE_N': 64, 'BLOCK_SIZE_K': 32, 'GROUP_SIZE_M': 8}, num_stages=4, num_warps=4),
triton.Config({'BLOCK_SIZE_M': 64, 'BLOCK_SIZE_N': 256, 'BLOCK_SIZE_K': 32, 'GROUP_SIZE_M': 8}, num_stages=4, num_warps=4),
triton.Config({'BLOCK_SIZE_M': 128, 'BLOCK_SIZE_N': 128, 'BLOCK_SIZE_K': 32, 'GROUP_SIZE_M': 8}, num_stages=4, num_warps=4),
triton.Config({'BLOCK_SIZE_M': 128, 'BLOCK_SIZE_N': 64, 'BLOCK_SIZE_K': 32, 'GROUP_SIZE_M': 8}, num_stages=4, num_warps=4),
triton.Config({'BLOCK_SIZE_M': 64, 'BLOCK_SIZE_N': 128, 'BLOCK_SIZE_K': 32, 'GROUP_SIZE_M': 8}, num_stages=4, num_warps=4),
triton.Config({'BLOCK_SIZE_M': 128, 'BLOCK_SIZE_N': 32, 'BLOCK_SIZE_K': 32, 'GROUP_SIZE_M': 8}, num_stages=4, num_warps=4),
triton.Config({'BLOCK_SIZE_M': 64, 'BLOCK_SIZE_N': 32, 'BLOCK_SIZE_K': 32, 'GROUP_SIZE_M': 8}, num_stages=5, num_warps=2),
triton.Config({'BLOCK_SIZE_M': 32, 'BLOCK_SIZE_N': 64, 'BLOCK_SIZE_K': 32, 'GROUP_SIZE_M': 8}, num_stages=5, num_warps=2),
],
key=['M', 'N', 'K'],
)
@triton.jit
def matmul_kernel(
# Pointers to matrices
a_ptr, b_ptr, c_ptr,
# Matrix dimensions
M, N, K,
# The stride variables represent how much to increase the ptr by when moving by 1
# element in a particular dimension. E.g. stride_am is how much to increase a_ptr
# by to get the element one row down (A has M rows)
stride_am, stride_ak,
stride_bk, stride_bn,
stride_cm, stride_cn,
# Meta-parameters
BLOCK_SIZE_M: tl.constexpr, BLOCK_SIZE_N: tl.constexpr, BLOCK_SIZE_K: tl.constexpr,
GROUP_SIZE_M: tl.constexpr,
ACTIVATION: tl.constexpr,
):
"""Kernel for computing the matmul C = A x B.
A has shape (M, K), B has shape (K, N) and C has shape (M, N)
"""
# -----------------------------------------------------------
# Map program ids `pid` to the block of C it should compute.
# This is done in a grouped ordering to promote L2 data reuse
# See above `L2 Cache Optimizations` section for details
pid = tl.program_id(axis=0)
num_pid_m = tl.cdiv(M, BLOCK_SIZE_M)
num_pid_n = tl.cdiv(N, BLOCK_SIZE_N)
num_pid_in_group = GROUP_SIZE_M * num_pid_n
group_id = pid // num_pid_in_group
first_pid_m = group_id * GROUP_SIZE_M
group_size_m = min(num_pid_m - first_pid_m, GROUP_SIZE_M)
pid_m = first_pid_m + (pid % group_size_m)
pid_n = (pid % num_pid_in_group) // group_size_m
# ----------------------------------------------------------
# Create pointers for the first blocks of A and B.
# We will advance this pointer as we move in the K direction
# and accumulate
# a_ptrs is a block of [BLOCK_SIZE_M, BLOCK_SIZE_K] pointers
# b_ptrs is a block of [BLOCK_SIZE_K, BLOCK_SIZE_n] pointers
# see above `Pointer Arithmetics` section for details
offs_am = pid_m * BLOCK_SIZE_M + tl.arange(0, BLOCK_SIZE_M)
offs_bn = pid_n * BLOCK_SIZE_N + tl.arange(0, BLOCK_SIZE_N)
offs_k = tl.arange(0, BLOCK_SIZE_K)
a_ptrs = a_ptr + (offs_am[:, None] * stride_am + offs_k[None, :] * stride_ak)
b_ptrs = b_ptr + (offs_k[:, None] * stride_bk + offs_bn[None, :] * stride_bn)
# -----------------------------------------------------------
# Iterate to compute a block of the C matrix
# We accumulate into a `[BLOCK_SIZE_M, BLOCK_SIZE_N]` block
# of fp32 values for higher accuracy.
# `accumulator` will be converted back to fp16 after the loop
accumulator = tl.zeros((BLOCK_SIZE_M, BLOCK_SIZE_N), dtype=tl.float32)
for k in range(0, K, BLOCK_SIZE_K):
# Note that for simplicity, we don't apply a mask here.
# This means that if K is not a multiple of BLOCK_SIZE_K,
# this will access out-of-bounds memory and produce an
# error or (worse!) incorrect results.
a = tl.load(a_ptrs)
b = tl.load(b_ptrs)
# We accumulate along the K dimension
accumulator += tl.dot(a, b)
# Advance the ptrs to the next K block
a_ptrs += BLOCK_SIZE_K * stride_ak
b_ptrs += BLOCK_SIZE_K * stride_bk
# you can fuse arbitrary activation functions here
# while the accumulator is still in FP32!
if ACTIVATION == "leaky_relu":
accumulator = leaky_relu(accumulator)
c = accumulator.to(tl.float16)
# -----------------------------------------------------------
# Write back the block of the output matrix C
offs_cm = pid_m * BLOCK_SIZE_M + tl.arange(0, BLOCK_SIZE_M)
offs_cn = pid_n * BLOCK_SIZE_N + tl.arange(0, BLOCK_SIZE_N)
c_ptrs = c_ptr + stride_cm * offs_cm[:, None] + stride_cn * offs_cn[None, :]
c_mask = (offs_cm[:, None] < M) & (offs_cn[None, :] < N)
tl.store(c_ptrs, c, mask=c_mask)
# we can fuse `leaky_relu` by providing it as an `ACTIVATION` meta-parameter in `_matmul`
@triton.jit
def leaky_relu(x):
x = x + 1
return tl.where(x >= 0, x, 0.01 * x)
def matmul(a, b, activation=""):
# checks constraints
assert a.shape[1] == b.shape[0], "incompatible dimensions"
assert a.is_contiguous(), "matrix A must be contiguous"
assert b.is_contiguous(), "matrix B must be contiguous"
M, K = a.shape
K, N = b.shape
assert (
K % 32 == 0
), "We don't check memory-out-of-bounds with K so K must be divisible by BLOCK_SIZE_K"
# allocates output
c = torch.empty((M, N), device=a.device, dtype=a.dtype)
# 1D launch kernel where each block gets its own program.
grid = lambda META: (
triton.cdiv(M, META['BLOCK_SIZE_M']) * triton.cdiv(N, META['BLOCK_SIZE_N']),
)
matmul_kernel[grid](
a, b, c,
M, N, K,
a.stride(0), a.stride(1),
b.stride(0), b.stride(1),
c.stride(0), c.stride(1),
ACTIVATION=activation,
)
return c
torch.manual_seed(0)
a = torch.randn((512, 512), device='cuda', dtype=torch.float16)
b = torch.randn((512, 512), device='cuda', dtype=torch.float16)
triton_output = matmul(a, b)
torch_output = torch.matmul(a, b)
print(f"triton_output={triton_output}")
print(f"torch_output={torch_output}")
if triton.testing.allclose(triton_output, torch_output):
print("✅ Triton and Torch match")
else:
print("❌ Triton and Torch differ")