On Fri, 2017-08-04 at 09:38 -0700, Shaohua Li wrote: > From: Shaohua Li <s...@fb.com> > > In a syn flooding test, the fib6_table rwlock is a significant > bottleneck. While converting the rwlock to rcu sounds straighforward, > but is very challenging if it's possible. A percpu spinlock (lglock has > been removed from kernel, so I added a simple implementation here) is > quite trival for this problem since updating the routing table is a rare > event. In my test, the server receives around 1.5 Mpps in syn flooding > test without the patch in a dual sockets and 56-CPU system. With the > patch, the server receives around 3.8Mpps, and perf report doesn't show > the locking issue. > > Of course the percpu lock isn't as good as rcu, so this isn't intended > to replace rcu, but this is much better than current readwrite lock. > Before we have a rcu implementation, this is a good temporary solution. > Plus, this is a trival change, there is nothing to prevent pursuing a > rcu implmentation. > > Cc: Wei Wang <wei...@google.com> > Cc: Eric Dumazet <eric.duma...@gmail.com> > Cc: Stephen Hemminger <step...@networkplumber.org> > Signed-off-by: Shaohua Li <s...@fb.com> > ---
Wei has almost done the RCU conversion. This patch is probably coming too late.
