From: NeilBrown <n...@brown.name> Date: Mon, 17 Dec 2018 09:08:54 +1100
> In my 4.4 kernel, the build_skb() call in (the equivalent of) > mtk_poll_rx() takes about 1.2usec and the call to napi_gro_receive() > takes about 3usec. > > In my 4.20 kernel, these calls take about 30 and 24 usec respectively. > This easily explains the slowdown. That's a huge difference. Nothing jumps out as a possible cause except perhaps retpoline or something like that.
