Note that this extension is considered buggy. See https://wiki.php.net/rfc/cli_process_title, which says:
"...but it is incomplete and might lead to memory corruption on Linux (or any OS which does not support setproctitle.
The reason is the extension only has access to original argv (that comes from main()). argv and environ(7) are in contiguous memory space on Linux. The extension presumes that argv can accomodate 128 characters, but usually that is not possible because argv is “php”. When this happens, the extension will scribble on argv, argv, etc., and maybe even environ and this can have destructive side effects on the running program."