setNproc = false
	case "aix":
		nproc = 9
	case "linux":
		nproc = 6
	case "darwin", "dragonfly", "freebsd", "netbsd", "openbsd":
		nproc = 7
	}
	if setNproc {
		var rlim syscall.Rlimit
		if syscall.Getrlimit(nproc, &rlim) == nil {
			max := int(rlim.Cur) / (threads + 5)
			if attempts > max {
				t.Logf("lowering attempts from %d to %d for RLIMIT_NPROC", attempts, max)
				attempts = max
			}
		}
	}