From: 吉藤英明 <hideaki.yoshif...@miraclelinux.com> Date: Sat, 7 Oct 2017 18:25:13 +0900
> Hi, > > 2017-10-07 8:49 GMT+09:00 Eric Dumazet <eric.duma...@gmail.com>: >> On Fri, 2017-10-06 at 12:05 -0700, Wei Wang wrote: >>> From: Wei Wang <wei...@google.com> >>> >>> Currently, fib6 table is protected by rwlock. During route lookup, >>> reader lock is taken and during route insertion, deletion or >>> modification, writer lock is taken. This is a very inefficient >>> implementation because the fastpath always has to do the operation >>> to grab the reader lock. >>> According to my latest syn flood test on an iota ivybridage machine >>> with 2 10G mlx nics bonded together, each with 8 rx queues on 2 NUMA >>> nodes, and with the upstream net-next kernel: >>> ipv4 stack can handle around 4.2Mpps >>> ipv6 stack can handle around 1.3Mpps >>> >>> In order to close the gap of the performance number between ipv4 >>> and ipv6 stack, this patch series tries to get rid of the usage of >>> the rwlock and replace it with rcu and spinlock protection. This will >>> greatly speed up the fastpath performance as it only needs to hold >>> rcu which is much less expensive than grabbing the reader lock. It >>> also makes ipv6 fib implementation more consistent with ipv4. ... >> Awesome work Wei. >> >> For the whole series : >> >> Reviewed-by: Eric Dumazet <eduma...@google.com> > > It looks ok to me. > Reviewed-by: YOSHIFUJI Hideaki <yoshf...@linux-ipv6.org> I have some reservations about these changes, fib6_info gets bigger, etc. And even with the amazing developers that helped review and audit these changes already, I can guarantee there are some bugs in here just like there were bugs in the ipv4 routing cache removal I did :-) But those don't block integration, for sure. So series applied, thanks a lot for doing this! I think there is some code that doesn't use proper RCU accessors for rt6i_exception_bucket. For example there are some assignments of it to NULL that should use RCU_ASSIGN_FOO() or similar. Please take a lok and fix those up. Thanks!
