On Sun, Apr 08, 2018 at 08:41:21PM +0200, Wenhua Shi wrote: > 2018-04-08 18:51 GMT+02:00 David Miller <da...@davemloft.net>: > > > > From: Wenhua Shi <march...@gmail.com> > > Date: Fri, 6 Apr 2018 03:43:39 +0200 > > > > > Signed-off-by: Wenhua Shi <march...@gmail.com> > > > > This precondition should be made impossible instead of having to do > > an extra check everywhere that this helper is invoked, many of which > > are in fast paths. > > I believe the precondition you said is quite true. In my situation, I > have to disable GSO for some packet and I notice that it leads to a > worse performance (slower than 1Mbps, was almost 800Mbps). > > Here's the hook I use on debian 9.4, kernel version 4.9:
There is quite a distance between 4.9 and net/net-next. Did you test on a more recent kernel too? Note that TCP stack now works with GSO being always on. 0a6b2a1dc2a2 ("tcp: switch to GSO being always on")