On Fri, 30 Oct 2020 18:34:12 -0700 Yuchung Cheng wrote: > During TCP fast recovery, the congestion control in charge is by > default the Proportional Rate Reduction (PRR) unless the congestion > control module specified otherwise (e.g. BBR). > > Previously when tcp_packets_in_flight() is below snd_ssthresh PRR > would slow start upon receiving an ACK that > 1) cumulatively acknowledges retransmitted data > and > 2) does not detect further lost retransmission > > Such conditions indicate the repair is in good steady progress > after the first round trip of recovery. Otherwise PRR adopts the > packet conservation principle to send only the amount that was > newly delivered (indicated by this ACK). > > This patch generalizes the previous design principle to include > also the newly sent data beside retransmission: as long as > the delivery is making good progress, both retransmission and > new data should be accounted to make PRR more cautious in slow > starting. > > Suggested-by: Matt Mathis <[email protected]> > Suggested-by: Neal Cardwell <[email protected]> > Signed-off-by: Yuchung Cheng <[email protected]> > Signed-off-by: Neal Cardwell <[email protected]> > Signed-off-by: Eric Dumazet <[email protected]>
Applied, thanks!
