From: Eric Dumazet <[email protected]> Date: Tue, 20 Sep 2016 22:45:58 -0700
> From: Eric Dumazet <[email protected]> > > We saw sch_fq drops caused by the per flow limit of 100 packets and TCP > when dealing with large cwnd and bursts of retransmits. > > Even after increasing the limit to 1000, and even after commit > 10d3be569243 ("tcp-tso: do not split TSO packets at retransmit time"), > we can still have these drops. > > Under certain conditions, TCP can spend a considerable amount of > time queuing thousands of skbs in a single tcp_xmit_retransmit_queue() > invocation, incurring latency spikes and stalls of other softirq > handlers. > > This patch implements TSQ for retransmits, limiting number of packets > and giving more chance for scheduling packets in both ways. > > Signed-off-by: Eric Dumazet <[email protected]> > Signed-off-by: Yuchung Cheng <[email protected]> > Signed-off-by: Neal Cardwell <[email protected]> Applied.
