BBR Patch

bbr.patch

--- a/net/ipv4/tcp_bbr.c
+++ b/net/ipv4/tcp_bbr.c
@@ -120,9 +120,9 @@ struct bbr {
 #define CYCLE_LEN	8	/* number of phases in a pacing gain cycle */
 
 /* Window length of bw filter (in rounds): */
-static const int bbr_bw_rtts = CYCLE_LEN + 2;
+static const int bbr_bw_rtts = CYCLE_LEN + 7;
 /* Window length of min_rtt filter (in sec): */
-static const u32 bbr_min_rtt_win_sec = 10;
+static const u32 bbr_min_rtt_win_sec = 20;
 /* Minimum time (in ms) spent at bbr_cwnd_min_target in BBR_PROBE_RTT mode: */
 static const u32 bbr_probe_rtt_mode_ms = 200;
 /* Skip TSO below the following bandwidth (bits/sec): */
@@ -137,15 +137,15 @@ static const int bbr_high_gain  = BBR_UN
 /* The pacing gain of 1/high_gain in BBR_DRAIN is calculated to typically drain
  * the queue created in BBR_STARTUP in a single round:
  */
-static const int bbr_drain_gain = BBR_UNIT * 1000 / 2885;
+static const int bbr_drain_gain = BBR_UNIT * 1200 / 2885;
 /* The gain for deriving steady-state cwnd tolerates delayed/stretched ACKs: */
 static const int bbr_cwnd_gain  = BBR_UNIT * 2;
 /* The pacing_gain values for the PROBE_BW gain cycle, to discover/share bw: */
 static const int bbr_pacing_gain[] = {
-	BBR_UNIT * 5 / 4,	/* probe for more available bw */
+	BBR_UNIT * 3 / 2,	/* probe for more available bw */
 	BBR_UNIT * 3 / 4,	/* drain queue and/or yield bw to other flows */
-	BBR_UNIT, BBR_UNIT, BBR_UNIT,	/* cruise at 1.0*bw to utilize pipe, */
-	BBR_UNIT, BBR_UNIT, BBR_UNIT	/* without creating excess queue... */
+	BBR_UNIT * 9 / 8, BBR_UNIT * 9 / 8, BBR_UNIT * 9 / 8,	/* cruise at 1.0*bw to utilize pipe, */
+	BBR_UNIT * 9 / 8, BBR_UNIT * 9 / 8, BBR_UNIT * 9 / 8	/* without creating excess queue... */
 };
 /* Randomize the starting gain cycling phase over N phases: */
 static const u32 bbr_cycle_rand = 7;
@@ -401,7 +401,7 @@ static void bbr_set_cwnd(struct sock *sk
 done:
 	tp->snd_cwnd = min(cwnd, tp->snd_cwnd_clamp);	/* apply global cap */
 	if (bbr->mode == BBR_PROBE_RTT)  /* drain queue, refresh min_rtt */
-		tp->snd_cwnd = min(tp->snd_cwnd, bbr_cwnd_min_target);
+		tp->snd_cwnd = max(tp->snd_cwnd >> 1, bbr_cwnd_min_target);
 }
 
 /* End cycle phase if it's time and/or we hit the phase's in-flight target. */
@@ -755,7 +755,7 @@ static void bbr_update_min_rtt(struct so
 		if (!bbr->probe_rtt_done_stamp &&
 		    tcp_packets_in_flight(tp) <= bbr_cwnd_min_target) {
 			bbr->probe_rtt_done_stamp = tcp_jiffies32 +
-				msecs_to_jiffies(bbr_probe_rtt_mode_ms);
+				msecs_to_jiffies(bbr_probe_rtt_mode_ms >> 1);
 			bbr->probe_rtt_round_done = 0;
 			bbr->next_rtt_delivered = tp->delivered;
 		} else if (bbr->probe_rtt_done_stamp) {