基于__torch_dispatch__机制的dump方法

之前拦截torch和torch.Tensor的办法,在处理backward时,不能看到aten算子的细节.以下基于__torch_dispatch__机制的方案更节约代码,且能看到调用栈

1.参考链接

[原理] (https://dev-discuss.pytorch.org/t/what-and-why-is-torch-dispatch/557)

2.原理

3.代码

import os
os.environ['CUDA_LAUNCH_BLOCKING'] = '1'
import torch
from torch import nn
import math
import torch.nn.functional as F
from torch.autograd import Variable
import time
import os
import threading

device="cuda"
from torch.utils._python_dispatch import TorchDispatchMode
import inspect
import traceback
from dataclasses import dataclass
from typing import Any

@dataclass
class _ProfilerState:
    cls: Any
    object: Any = None

lock=threading.Lock()
gindex=0
def save_tensor(name,args,index=0):
    if isinstance(args,torch.Tensor):
        print(name,index,args.shape)
        global gindex
        lock.acquire()
        torch.save(args,"{}_{}_{}_{}.pt".format(device,gindex,name,index))
        gindex+=1
        lock.release()
    if isinstance(args,tuple):
        for idx,x in enumerate(args):
            save_tensor(name,x,index+idx)

class TorchDumpDispatchMode(TorchDispatchMode):
    def __init__(self,parent):
        super().__init__()
        self.parent=parent
    def __torch_dispatch__(self, func, types, args=(), kwargs=None):
        func_packet = func._overloadpacket        
        if kwargs is None:
            kwargs = {}        
        enable_dump=False
        if func_packet.__name__ not in ["detach"]:
            enable_dump=True
            print(f"Profiling {func_packet.__name__}") 
            for idx,stack in enumerate(inspect.stack()):
                print(f'{"*"*idx}{stack.filename}{stack.lineno}')
        if enable_dump:     
            save_tensor(f"{func_packet.__name__}-input",args)
        ret= func(*args, **kwargs)
        if enable_dump:
            save_tensor(f"{func_packet.__name__}-output",ret)
        return ret

class TorchDumper:
    _CURRENT_Dumper = None
    def __init__(self,schedule: Any):
        self.p= _ProfilerState(schedule) 

    def __enter__(self):
        assert TorchDumper._CURRENT_Dumper is None
        TorchDumper._CURRENT_Dumper = self
        if self.p.object is None:
            o = self.p.cls(self)
            o.__enter__()
            self.p.object = o
        else:
            self.p.object.step()
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        TorchDumper._CURRENT_Dumper = None
        if self.p.object is not None:
            self.p.object.__exit__(exc_type, exc_val, exc_tb)

class Attention(nn.Module):
    def __init__(self,max_seq_len,head_dim,flash):
        super().__init__()
        self.flash = flash
        self.dropout=0
        self.attn_dropout = nn.Dropout(self.dropout)
        self.head_dim=head_dim
        if not self.flash:
            print("WARNING: using slow attention. Flash Attention requires PyTorch >= 2.0")
            mask = torch.full((1, 1, max_seq_len, max_seq_len), float("-inf")).to(device)
            mask = torch.triu(mask, diagonal=1).half().to(device)
            self.register_buffer("mask", mask)		
    def forward(
            self,xq: torch.Tensor,xk: torch.Tensor,xv: torch.Tensor):
        if self.flash:
            output = torch.nn.functional.scaled_dot_product_attention(xq, xk, xv,
                                                                       attn_mask=None, 
                                                                       dropout_p=self.dropout if self.training else 0.0, is_causal=True)
        else:
            _xk=xk.clone()
            t=_xk.transpose(2, 3)
            scores = torch.matmul(xq,t)
            scores = scores/math.sqrt(self.head_dim)
            a=self.mask[:, :, :seqlen, :seqlen]
            scores = scores+a
            scores = F.softmax(scores.float(), dim=-1)
            scores = scores.type_as(xq)
            scores = self.attn_dropout(scores)
            output = torch.matmul(scores, xv)  
        return output

def main(flash,bs, n_local_heads, seqlen, head_dim):
    torch.random.manual_seed(1)

    q = torch.ones((bs, n_local_heads, seqlen, head_dim),dtype=torch.float32).half().to(device)
    k = torch.ones((bs, n_local_heads, seqlen, head_dim),dtype=torch.float32).half().to(device)
    v = torch.ones((bs, n_local_heads, seqlen, head_dim),dtype=torch.float32).half().to(device)

    q.data.normal_(0, 0.1)
    k.data.normal_(0, 0.1)
    v.data.normal_(0, 0.1)

    q=Variable(q, requires_grad=True).to(device)
    k=Variable(k, requires_grad=True).to(device)
    v=Variable(v, requires_grad=True).to(device)

    gt= torch.randint(0,head_dim,(bs*n_local_heads*seqlen,1)).reshape(-1).to(device)
    loss_func=nn.CrossEntropyLoss().to(device)

    model=Attention(seqlen,head_dim,flash).half().to(device)
    optim = torch.optim.SGD([q,k,v], lr=1.1)

    with TorchDumper(TorchDumpDispatchMode):
        for i in range(1):
            output = model(q,k,v)
            loss=loss_func(output.reshape(-1,head_dim),gt)
            loss.backward()  
            optim.step()
            print("{:.5f},{:.5f},{:.5f},{:.5f}".format(q.sum().item(),k.sum().item(),v.sum().item(),loss.item()))

bs, n_local_heads, seqlen, head_dim = 8, 8, 512, 64
main(False,bs, n_local_heads, seqlen, head_dim)
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4.效果

Profiling clone
/home/user/proj/attention/attention_torch_dispatch_dumper.py60
*/home/user/proj/attention/attention_torch_dispatch_dumper.py109
**/home/anaconda3/envs/nvidia_training/lib/python3.10/site-packages/torch/nn/modules/module.py1527
***/home/anaconda3/envs/nvidia_training/lib/python3.10/site-packages/torch/nn/modules/module.py1518
****/home/user/proj/attention/attention_torch_dispatch_dumper.py144
*****/home/user/proj/attention/attention_torch_dispatch_dumper.py151
clone-input 0 torch.Size([8, 8, 512, 64])
clone-output 0 torch.Size([8, 8, 512, 64])
Profiling transpose
/home/user/proj/attention/attention_torch_dispatch_dumper.py60
*/home/user/proj/attention/attention_torch_dispatch_dumper.py110
**/home/anaconda3/envs/nvidia_training/lib/python3.10/site-packages/torch/nn/modules/module.py1527
***/home/anaconda3/envs/nvidia_training/lib/python3.10/site-packages/torch/nn/modules/module.py1518
****/home/user/proj/attention/attention_torch_dispatch_dumper.py144
*****/home/user/proj/attention/attention_torch_dispatch_dumper.py151
transpose-input 0 torch.Size([8, 8, 512, 64])
transpose-output 0 torch.Size([8, 8, 512, 64])
Profiling expand
/home/user/proj/attention/attention_torch_dispatch_dumper.py60
*/home/user/proj/attention/attention_torch_dispatch_dumper.py111
**/home/anaconda3/envs/nvidia_training/lib/python3.10/site-packages/torch/nn/modules/module.py1527
***/home/anaconda3/envs/nvidia_training/lib/python3.10/site-packages/torch/nn/modules/module.py1518
****/home/user/proj/attention/attention_torch_dispatch_dumper.py144
*****/home/user/proj/attention/attention_torch_dispatch_dumper.py151
expand-input 0 torch.Size([8, 8, 512, 64])
expand-output 0 torch.Size([8, 8, 512, 64])
Profiling view
/home/user/proj/attention/attention_torch_dispatch_dumper.py60
*/home/user/proj/attention/attention_torch_dispatch_dumper.py111
**/home/anaconda3/envs/nvidia_training/lib/python3.10/site-packages/torch/nn/modules/module.py1527
***/home/anaconda3/envs/nvidia_training/lib/python3.10/site-packages/torch/nn/modules/module.py1518
****/home/user/proj/attention/attention_torch_dispatch_dumper.py144
*****/home/user/proj/attention/attention_torch_dispatch_dumper.py151
view-input 0 torch.Size([8, 8, 512, 64])
view-output 0 torch.Size([8, 8, 512, 64])
Profiling expand
/home/user/proj/attention/attention_torch_dispatch_dumper.py60
*/home/user/proj/attention/attention_torch_dispatch_dumper.py111
**/home/anaconda3/envs/nvidia_training/lib/python3.10/site-packages/torch/nn/modules/module.py1527
***/home/anaconda3/envs/nvidia_training/lib/python3.10/site-packages/torch/nn/modules/module.py1518
****/home/user/proj/attention/attention_torch_dispatch_dumper.py144
*****/home/user/proj/attention/attention_torch_dispatch_dumper.py151
expand-input 0 torch.Size([8, 8, 64, 512])
expand-output 0 torch.Size([8, 8, 64, 512])
Profiling view
/home/user/proj/attention/attention_torch_dispatch_dumper.py60
*/home/user/proj/attention/attention_torch_dispatch_dumper.py111
**/home/anaconda3/envs/nvidia_training/lib/python3.10/site-packages/torch/nn/modules/module.py1527
***/home/anaconda3/envs/nvidia_training/lib/python3.10/site-packages/torch/nn/modules/module.py1518
****/home/user/proj/attention/attention_torch_dispatch_dumper.py144
*****/home/user/proj/attention/attention_torch_dispatch_dumper.py151
view-input 0 torch.Size([8, 8, 64, 512])
view-output 0 torch.Size([8, 8, 64, 512])
Profiling bmm
/home/user/proj/attention/attention_torch_dispatch_dumper.py60
*/home/user/proj/attention/attention_torch_dispatch_dumper.py111
**/home/anaconda3/envs/nvidia_training/lib/python3.10/site-packages/torch/nn/modules/module.py1527
***/home/anaconda3/envs/nvidia_training/lib/python3.10/site-packages/torch/nn/modules/module.py1518
****/home/user/proj/attention/attention_torch_dispatch_dumper.py144
*****/home/user/proj/attention/attention_torch_dispatch_dumper.py151
bmm-input 0 torch.Size([64, 512, 64])
bmm-input 1 torch.Size([64, 64, 512])
bmm-output 0 torch.Size([64, 512, 64])
bmm-output 1 torch.Size([64, 64, 512])
Profiling _unsafe_view
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