Solved by cryptopic in post #4 
              
              
                @Jimmy2027:  I was able to make logging work by moving SummaryWriter creation from main process to child process, specifically remove 
self.logger = SummaryWriter(dir_logs)

And add in run_epochs 
exp.logger = SummaryWriter(exp.dir_logs)

So that we don’t have to folk the lock inside SummaryWriter (…