if gomaxprocs <= 1 {
		return
	}
	gp := getg()
	if gp == nil || gp.m == nil || gp.m.p == 0 {
		return
	}
	myID := gp.m.p.ptr().id
	for tries := 0; tries < 5; tries++ {
		id := int32(cheaprandn(uint32(gomaxprocs - 1)))
		if id >= myID {
			id++
		}
		p := allp[id]
		if p.status != _Prunning {
			continue
		}
		if preemptone(p) {
			return
		}
	}
}