Hi,
I have the same problem on a Debian server. Finally, I realized that the number of workers should be zero for the best performance, which contradicts the official guideline. Similar situation:

  
      github.com/pytorch/pytorch
  
  
    



Issue: In windows, DataLoader with num_workers > 0 is extremely slow (50 times slower) 39


	
	opened by taohu88
	on 2018-10-18
	
	
	


🐛 Bug
In windows, DataLoader with num_workers > 0 is extremely slow (pytorch=0.41)
To Reproduce
Step 1: create two loader, one with num_workers and...


 	high priority
 	module: multiprocessing
 	module: windows
 	triaged


  
  
    
    
  
  



  
      
      Deep Learning Course Forums – 1 Jul 19
  
  
    

Very slow dataloader 21

This explains a lot!  I assumed the speed I was getting in windows was normal until I tried fastai in Ubuntu on my system on the exact same notebook, and it ran / trained ~3x faster.  On my hardware, your fix took an unet / resnet101 128x128x3 BS = 8...


  
  
    
    
  
  


Best,
Sina