css animate属性写的平移动画卡顿

这是我用了的属性，还少了什么？

.topDiv .cloundBig{
    width: 10rem;
    animation-duration:8s;
    animation-name: cloundBig;
    animation-timing-function: linear;
    animation-iteration-count: infinite;
    animation-direction: alternate;
}
@-webkit-keyframes cloundBig {
    0% { margin-left: 50% }
    100% { margin-left: 60% }
}

---

animation: name duration timing-function delay iteration-count direction;

还有 卡顿发生在什么浏览器？