tcp: Fix tcp_hybla zero congestion window growth with small rho and large cwnd. (9d2c27e1) · Commits · 戴 / test

Because of rounding, in certain conditions, i.e. when in congestion avoidance state rho is smaller than 1/128 of the current cwnd, TCP Hybla congestion control starves and the cwnd is kept constant forever. This patch forces an increment by one segment after #send_cwnd calls without increments(newreno behavior). Signed-off-by:

Daniele Lacamera <root@danielinux.net> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/ipv4/tcp_hybla.c

+5 −1

Original line number	Original line	Diff line number	Diff line
	@@ -150,7 +150,11 @@ static void hybla_cong_avoid(struct sock *sk, u32 ack, u32 in_flight)
	ca->snd_cwnd_cents -= 128;		ca->snd_cwnd_cents -= 128;
	tp->snd_cwnd_cnt = 0;		tp->snd_cwnd_cnt = 0;
	}		}
			/* check when cwnd has not been incremented for a while */
			if (increment == 0 && odd == 0 && tp->snd_cwnd_cnt >= tp->snd_cwnd) {
			tp->snd_cwnd++;
			tp->snd_cwnd_cnt = 0;
			}
	/* clamp down slowstart cwnd to ssthresh value. */		/* clamp down slowstart cwnd to ssthresh value. */
	if (is_slowstart)		if (is_slowstart)
	tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh);		tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh);

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