# some debug notes / code - wip Debug spikes suggestions: - analyse restore from state_dict for word embedding V try to comment out update lp params - with normal lr results are much worse - moved from 3.5 to 5.5 loss - try again w/ lr=0 ``` # deepspeed/runtime/bf16_optimizer.py def update_lp_params(self): return ``` - norm of activations to know which part gets out of sync V run optimizer with LR=0 - ``` perl -le 'print qx[diff -u debug-emb-bf16-$_-pp0-tp0-dp0-$ARGV[1]-iteration.txt debug-emb-bf16-$_-pp1-tp0-dp0-$ARGV[1]-iteration.txt] for $ARGV[0]' 1 before - perl -le 'do { print qx[diff -u debug-$_-pp0-tp0-dp0-global0-on-save*.txt debug-$_-pp1-tp0-dp0-global1-on-save*.txt]; print qx[diff -u debug-$_-pp0-tp0-dp0-global0-on-load*.txt debug-$_-pp1-tp0-dp0-global1-on-load*.txt] } for 15..15' perl -le 'do { print qx[diff -u debug-$_-pp0-tp0-dp0-global0-on-save*.txt debug-$_-pp0-tp0-dp0-global0-on-load*.txt]; print qx[diff -u debug-$_-pp1-tp0-dp0-global1-on-save*.txt debug-$_-pp1-tp0-dp0-global1-on-load*.txt] } for 15..15' perl -le '$_=shift; do { print qx[diff -u debug-$_-pp0-tp0-dp0-global0-on-save*.txt debug-$_-pp1-tp0-dp0-global1-on-save*.txt]; print qx[diff -u debug-$_-pp0-tp0-dp0-global0-on-load*.txt debug-$_-pp1-tp0-dp0-global1-on-load*.txt] } ' 5 perl -le '$_=shift; do { print qx[diff -u debug-$_-pp0-tp0-dp0-global0-on-save*.txt debug-$_-pp0-tp0-dp0-global0-on-load*.txt]; print qx[diff -u debug-$_-pp1-tp0-dp0-global1-on-save*.txt debug-$_-pp1-tp0-dp0-global1-on-load*.txt] } ' 5 debug-12-pp0-tp0-dp0-global0-on-load-*.txt debug-13-pp0-tp0-dp0-global0-before-iteration-*.txt debug-$_-pp0-tp0-dp0-global0-before-iteration-*.txt debug-$_-pp0-tp0-dp0-global0-after-iteration-*.txt debug-bf16-21-pp0-tp1-before-iteration.txt debug-bf16-21-pp0-tp1-after-iteration.txt debug-fp32-21-pp1-tp0-before-iteration.txt debug-fp32-21-pp1-tp0-after-iteration.txt debug-bf16-21-pp0-tp1-before-iteration.txt debug-bf16-21-pp0-tp1-after-iteration.txt debug-fp32-21-pp1-tp0-before-iteration.txt debug-fp32-21-pp1-tp0-after-iteration.txt On each node - the same situation: (checked nodes 0 and 1 only) 6 processes are in: Thread 835990 (active): "MainThread" train (megatron/training.py:915) pretrain (megatron/training.py:187) (pretrain_gpt.py:239) 2 processes are in: Thread 835995 (active): "MainThread" broadcast (torch/distributed/distributed_c10d.py:1191) _aggregate_total_loss (deepspeed/runtime/pipe/engine.py:540) train_batch (deepspeed/runtime/pipe/engine.py:330) train_step (megatron/training.py:436) train (megatron/training.py:851) pretrain (megatron/training.py:187) (pretrain_gpt.py:239) ``` ## debugging setup ``` salloc --partition=gpu_p5 --constraint=a100 --reservation=hug --nodes=2 --ntasks-per-node=1 --cpus-per-task=64 --hint=nomultithread --gres=gpu:8 --time 20:00:00 --account=six@a100 ``` ``` bash 20B-n2-fp16.slurm ``` ``` function makehostfile() { perl -e '$slots=split /,/, $ENV{"SLURM_STEP_GPUS"}; $slots=8 if $slots==0; # workaround 8 gpu machines @nodes = split /\n/, qx[scontrol show hostnames $ENV{"SLURM_JOB_NODELIST"}]; print map { "$b$_ slots=$slots\n" } @nodes' } makehostfile > hostfile ``` ``` ds_ssh -f hostfile "source ~/.pdshrc; ps aux | grep python | grep -v grep | grep `whoami` | awk '{print \$2}' | xargs -I {} py-spy dump --pid {} " ``` ps aux | grep python | egrep -v '(srun|grep)' | grep `whoami` | awk '{print $2}' | xargs -I {} py-spy dump --pid {} must use `--gres=gpu:0` for the monitor or it'll block. ``` srun --gres=gpu:0 --jobid=$SLURM_JOBID ~/script.bash ``` ``` srun --jobid= --gres=gpu:0 -N --tasks-per-node=1 --output=%N.out sh -c 'ps aux | grep python | egrep -v "grep|srun" | grep `whoami` | awk "{print \$2}" | xargs -I {} py-spy dump --native --pid {}' ``` ``` #!/bin/bash ps aux | grep python | grep -v grep | grep `whoami` | awk '{print $2}' | xargs -I {} py-spy dump --pid {} ``` ``` ssh jean-zay-iam01 "~/script.bash" ``` # full debug ``` cd ~/prod/code/tr8b-104B/bigscience/train/tr11-200B-ml/ salloc --partition=gpu_p5 --constraint=a100 --reservation=hug --nodes=40 --ntasks-per-node=1 --cpus-per-task=64 --hint=nomultithread --gres=gpu:8 --time 20:00:00 --account=six@a100 bash 200B-n40-bf16-mono.slurm # in another shell squeue -u `whoami` -o "%.16i %.9P %.26j %.8T %.10M %.8l %.6D %.20S %R" # adjust jobid srun --jobid=2180718 --gres=gpu:0 --nodes=40 --tasks-per-node=1 --output=trace-%N.out sh -c 'ps aux | grep python | egrep -v "grep|srun" | grep `whoami` | awk "{print \$2}" | xargs -I {} py-spy dump --native --pid {}' || echo "failed" ``` ``` srun --jobid=4808 --gres=gpu:0 --nodes=48 --tasks-per-node=1 --output=trace-%N.out sh -c 'ps aux | grep python | egrep -v "grep|srun" | grep `whoami` | awk "{print \$2}" | xargs -I {} py-spy dump --native --pid {}' || echo "failed" ``` # using pdsh It's a bit tricky and doesn't work for `py-spy` # tracing with python trace This code will trace all python calls and log them to the console and into a dedicated per process log file. This then can help to understand where some processes stopped responding, since we will have the log of the last call before it went unresponsive. ``` $ cat pretrain_gpt.py [...] def main(): pretrain(train_valid_test_datasets_provider, model_provider, forward_step, args_defaults={'tokenizer_type': 'GPT2BPETokenizer'}) import re class Tee: """ A helper class to tee print's output into a file. Usage: sys.stdout = Tee(filename) """ def __init__(self, filename): self.stdout = sys.stdout self.file = open(filename, "a") def __getattr__(self, attr): return getattr(self.stdout, attr) def write(self, msg): self.stdout.write(msg) self.file.write(msg) self.file.flush() def flush(self): self.stdout.flush() self.file.flush() if __name__ == "__main__": import sys import trace import socket import os # enable to trace if 0: cwd = os.path.realpath('.') pid = os.getpid() hostname = socket.gethostname() local_rank = int(os.environ["LOCAL_RANK"]) trace_output_file = f"{cwd}/trace-{hostname}-{local_rank}-{pid}.txt" # create a Trace object, telling it what to ignore, and whether to # do tracing or line-counting or both. tracer = trace.Trace( ignoredirs=[sys.prefix, sys.exec_prefix], trace=1, count=1, ) # outfile=trace_output_file) # run the new command using the given tracer sys.stdout = Tee(trace_output_file) tracer.run('main()') else: main() ```