利用卡沙皮层和卡加射线层提高梯度边界的性能

I am using this method to apply gradient border to views. But when the view is in a cell of a tableview, the scrolling frame rate of the table view drops significally. Is there a way to improve the performance ? I tried setting the opaque , drawsAsynchronously and shouldRasterize to true as Apple is suggesting but nothing changed.I am using this method to apply gradient border