Re: [RFC PATCH net-next] ipv6: implement consistent hashing for equal-cost multipath routing

2016-12-01 Thread David Miller
From: Hannes Frederic Sowa Date: Wed, 30 Nov 2016 14:12:48 +0100 > David, one question: do you remember if you measured with linked lists > at that time or also with arrays. I actually would expect small arrays > that entirely fit into cachelines to be actually faster

Re: [RFC PATCH net-next] ipv6: implement consistent hashing for equal-cost multipath routing

2016-11-30 Thread Hannes Frederic Sowa
On Mon, Nov 28, 2016, at 21:32, David Miller wrote: > From: David Lebrun > Date: Mon, 28 Nov 2016 21:16:19 +0100 > > > The advantage of my solution over RFC2992 is lowest possible disruption > > and equal rebalancing of affected flows. The disadvantage is the lookup >

Re: [RFC PATCH net-next] ipv6: implement consistent hashing for equal-cost multipath routing

2016-11-28 Thread David Lebrun
On 11/28/2016 09:32 PM, David Miller wrote: > When I was working on the routing cache removal in ipv4 I compared > using a stupid O(1) hash lookup of the FIB entries vs. the O(log n) > fib_trie stuff actually in use. > > It did make a difference. > > This is a lookup that can be invoked 20

Re: [RFC PATCH net-next] ipv6: implement consistent hashing for equal-cost multipath routing

2016-11-28 Thread David Miller
From: David Lebrun Date: Mon, 28 Nov 2016 21:16:19 +0100 > The advantage of my solution over RFC2992 is lowest possible disruption > and equal rebalancing of affected flows. The disadvantage is the lookup > complexity of O(log n) vs O(1). Although from a theoretical

Re: [RFC PATCH net-next] ipv6: implement consistent hashing for equal-cost multipath routing

2016-11-28 Thread David Lebrun
On 11/28/2016 05:22 PM, David Miller wrote: > Thanks for trying to solve this problem. > > But we really don't want this to be Kconfig gated. If we decide to > support this it should be a run-time selectable option. Every > distribution on the planet is going to turn your Kconfig option on, so

Re: [RFC PATCH net-next] ipv6: implement consistent hashing for equal-cost multipath routing

2016-11-28 Thread David Miller
From: David Lebrun Date: Thu, 24 Nov 2016 20:59:16 +0100 > When multiple nexthops are available for a given route, the routing engine > chooses a nexthop by computing the flow hash through get_hash_from_flowi6 > and by taking that value modulo the number of nexthops.