From: Yuchung Cheng <ych...@google.com> Date: Wed, 4 Oct 2017 12:59:57 -0700
> This patch set improves the CPU consumption of the RACK TCP loss > recovery algorithm, in particular for high-speed networks. Currently, > for every ACK in recovery RACK can potentially iterate over all sent > packets in the write queue. On large BDP networks with non-trivial > losses the RACK write queue walk CPU usage becomes unreasonably high. > > This patch introduces a new queue in TCP that keeps only skbs sent and > not yet (s)acked or marked lost, in time order instead of sequence > order. With that, RACK can examine this time-sorted list and only > check packets that were sent recently, within the reordering window, > per ACK. This is the fastest way without any write queue walks. The > number of skbs examined per ACK is reduced by orders of magnitude. That's a pretty risky way to implement the second SKB list.... but you avoided making sk_buff larger so what can I say :-) Series applied, thank.
