Multiple machines cannot generate json files

[LLJJRR]

I cannot generate json files on 4 machines using this command：
ib_send_bw -d mlx5_1 --port 11040 --report_gbits -F -n 180000 --out_json --out_json_file=/path/to/your/output_file.json -x 0
but i can generate json files on 2 machines

[blochl]

@LLJJRR - What exactly is the issue? An error? A corrupt file? Something else?