Add flags to debug NCCL error

Author: liujch1998

scripts/beaker/ladder_peteish.sh

@@ -28,6 +28,10 @@ export NCCL_IB_HCA="^=mlx5_bond_0"
 export NCCL_SOCKET_IFNAME=ib
 # export NCCL_IB_GID_INDEX=0
 
+# debug flags for IB NCCL error
+export TORCH_SHOW_CPP_STACKTRACES=1
+export NCCL_INFO=DEBUG
+
 torchrun \
   --nnodes ${NUM_NODES}:${NUM_NODES} \
   --nproc-per-node 8 \