tcp: add helper for AI algorithm

It seems that implementation in yeah was inconsistent to what
other did as it would increase cwnd one ack earlier than the
others do.

Size benefits:

  bictcp_cong_avoid |  -36
  tcp_cong_avoid_ai |  +52
  bictcp_cong_avoid |  -34
  tcp_scalable_cong_avoid |  -36
  tcp_veno_cong_avoid |  -12
  tcp_yeah_cong_avoid |  -38

= -104 bytes total

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 218235de89637f9471027f299dfd19fcd9d6c858..0366a559afec035d503e2428a2658a1a4d2843d1 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -685,6 +685,7 @@ extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
 extern int tcp_set_allowed_congestion_control(char *allowed);
 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
 extern void tcp_slow_start(struct tcp_sock *tp);
+extern void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w);
 
 extern struct tcp_congestion_ops tcp_init_congestion_ops;
 extern u32 tcp_reno_ssthresh(struct sock *sk);

diff --git a/net/ipv4/tcp_bic.c b/net/ipv4/tcp_bic.c
index 7eb7636db0d0e0f0b0675d17de4b4a17db32d4b3..3b53fd1af23f04bb2a9023b56204ca45051fa81f 100644 (file)
--- a/net/ipv4/tcp_bic.c
+++ b/net/ipv4/tcp_bic.c
@@ -149,16 +149,7 @@ static void bictcp_cong_avoid(struct sock *sk, u32 ack, u32 in_flight)
                tcp_slow_start(tp);
        else {
                bictcp_update(ca, tp->snd_cwnd);
-
-               /* In dangerous area, increase slowly.
-                * In theory this is tp->snd_cwnd += 1 / tp->snd_cwnd
-                */
-               if (tp->snd_cwnd_cnt >= ca->cnt) {
-                       if (tp->snd_cwnd < tp->snd_cwnd_clamp)
-                               tp->snd_cwnd++;
-                       tp->snd_cwnd_cnt = 0;
-               } else
-                       tp->snd_cwnd_cnt++;
+               tcp_cong_avoid_ai(tp, ca->cnt);
        }
 
 }

diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 4ec5b4e97c4e2bc97a07e5887167e26b265b9e72..e92beb9e55e0d834c3184e4b2a5c6e4faa5ea057 100644 (file)
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -336,6 +336,19 @@ void tcp_slow_start(struct tcp_sock *tp)
 }
 EXPORT_SYMBOL_GPL(tcp_slow_start);
 
+/* In theory this is tp->snd_cwnd += 1 / tp->snd_cwnd (or alternative w) */
+void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w)
+{
+       if (tp->snd_cwnd_cnt >= w) {
+               if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+                       tp->snd_cwnd++;
+               tp->snd_cwnd_cnt = 0;
+       } else {
+               tp->snd_cwnd_cnt++;
+       }
+}
+EXPORT_SYMBOL_GPL(tcp_cong_avoid_ai);
+
 /*
  * TCP Reno congestion control
  * This is special case used for fallback as well.
@@ -365,13 +378,7 @@ void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight)
                                tp->snd_cwnd++;
                }
        } else {
-               /* In theory this is tp->snd_cwnd += 1 / tp->snd_cwnd */
-               if (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
-                       if (tp->snd_cwnd < tp->snd_cwnd_clamp)
-                               tp->snd_cwnd++;
-                       tp->snd_cwnd_cnt = 0;
-               } else
-                       tp->snd_cwnd_cnt++;
+               tcp_cong_avoid_ai(tp, tp->snd_cwnd);
        }
 }
 EXPORT_SYMBOL_GPL(tcp_reno_cong_avoid);

diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c
index ee467ec40c4f3c0b08123d042921c2f87481632f..71d5f2f29fa62b92cb4ae4d4762b5322d017f5d3 100644 (file)
--- a/net/ipv4/tcp_cubic.c
+++ b/net/ipv4/tcp_cubic.c
@@ -294,16 +294,7 @@ static void bictcp_cong_avoid(struct sock *sk, u32 ack, u32 in_flight)
                tcp_slow_start(tp);
        } else {
                bictcp_update(ca, tp->snd_cwnd);
-
-               /* In dangerous area, increase slowly.
-                * In theory this is tp->snd_cwnd += 1 / tp->snd_cwnd
-                */
-               if (tp->snd_cwnd_cnt >= ca->cnt) {
-                       if (tp->snd_cwnd < tp->snd_cwnd_clamp)
-                               tp->snd_cwnd++;
-                       tp->snd_cwnd_cnt = 0;
-               } else
-                       tp->snd_cwnd_cnt++;
+               tcp_cong_avoid_ai(tp, ca->cnt);
        }
 
 }

diff --git a/net/ipv4/tcp_scalable.c b/net/ipv4/tcp_scalable.c
index 4660b088a8ce4abe86ef64b18d4f007926b7424a..a76513779e2be92fdefbfba84091685bcdf3eaf3 100644 (file)
--- a/net/ipv4/tcp_scalable.c
+++ b/net/ipv4/tcp_scalable.c
@@ -24,14 +24,8 @@ static void tcp_scalable_cong_avoid(struct sock *sk, u32 ack, u32 in_flight)
 
        if (tp->snd_cwnd <= tp->snd_ssthresh)
                tcp_slow_start(tp);
-       else {
-               tp->snd_cwnd_cnt++;
-               if (tp->snd_cwnd_cnt > min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT)){
-                       if (tp->snd_cwnd < tp->snd_cwnd_clamp)
-                               tp->snd_cwnd++;
-                       tp->snd_cwnd_cnt = 0;
-               }
-       }
+       else
+               tcp_cong_avoid_ai(tp, min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT));
 }
 
 static u32 tcp_scalable_ssthresh(struct sock *sk)

diff --git a/net/ipv4/tcp_veno.c b/net/ipv4/tcp_veno.c
index d08b2e855c229334fcec88bb765cb26dbb6e34c7..e9bbff746488e6be777d538bf641fa6dd4244274 100644 (file)
--- a/net/ipv4/tcp_veno.c
+++ b/net/ipv4/tcp_veno.c
@@ -159,12 +159,7 @@ static void tcp_veno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight)
                                /* In the "non-congestive state", increase cwnd
                                 *  every rtt.
                                 */
-                               if (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
-                                       if (tp->snd_cwnd < tp->snd_cwnd_clamp)
-                                               tp->snd_cwnd++;
-                                       tp->snd_cwnd_cnt = 0;
-                               } else
-                                       tp->snd_cwnd_cnt++;
+                               tcp_cong_avoid_ai(tp, tp->snd_cwnd);
                        } else {
                                /* In the "congestive state", increase cwnd
                                 * every other rtt.

diff --git a/net/ipv4/tcp_yeah.c b/net/ipv4/tcp_yeah.c
index 9ec843a9bbb2507a9d96cc088ef6b167747ea603..66b6821b984ed6cde6d0f77bcaeb06baf0d21de7 100644 (file)
--- a/net/ipv4/tcp_yeah.c
+++ b/net/ipv4/tcp_yeah.c
@@ -94,14 +94,7 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack, u32 in_flight)
 
        } else {
                /* Reno */
-
-               if (tp->snd_cwnd_cnt < tp->snd_cwnd)
-                       tp->snd_cwnd_cnt++;
-
-               if (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
-                       tp->snd_cwnd++;
-                       tp->snd_cwnd_cnt = 0;
-               }
+               tcp_cong_avoid_ai(tp, tp->snd_cwnd);
        }
 
        /* The key players are v_vegas.beg_snd_una and v_beg_snd_nxt.