4 files changed, 28 insertions, 3 deletions

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index fdcd00ffcb66..a17ae7b85218 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -213,7 +213,8 @@ struct tcp_sock {
                 u8 reord;    /* reordering detected */
         } rack;
         u16     advmss;         /* Advertised MSS                       */
-        u8      unused;
+        u8      rate_app_limited:1,  /* rate_{delivered,interval_us} limited? */
+                unused:7;
         u8      nonagle     : 4,/* Disable Nagle algorithm?             */
                 thin_lto    : 1,/* Use linear timeouts for thin streams */
                 thin_dupack : 1,/* Fast retransmit on first dupack      */
@@ -271,6 +272,8 @@ struct tcp_sock {
         u32     app_limited;    /* limited until "delivered" reaches this val */
         struct skb_mstamp first_tx_mstamp;  /* start of window send phase */
         struct skb_mstamp delivered_mstamp; /* time we reached "delivered" */
+        u32     rate_delivered;    /* saved rate sample: packets delivered */
+        u32     rate_interval_us;  /* saved rate sample: time elapsed */
 
         u32     rcv_wnd;        /* Current receiver window              */
         u32     write_seq;      /* Tail(+1) of data held in tcp send buffer */
diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h
index 482898fc433a..73ac0db487f8 100644
--- a/include/uapi/linux/tcp.h
+++ b/include/uapi/linux/tcp.h
@@ -167,6 +167,7 @@ struct tcp_info {
         __u8    tcpi_backoff;
         __u8    tcpi_options;
         __u8    tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
+        __u8    tcpi_delivery_rate_app_limited:1;
 
         __u32   tcpi_rto;
         __u32   tcpi_ato;
@@ -211,6 +212,8 @@ struct tcp_info {
         __u32   tcpi_min_rtt;
         __u32   tcpi_data_segs_in;      /* RFC4898 tcpEStatsDataSegsIn */
         __u32   tcpi_data_segs_out;     /* RFC4898 tcpEStatsDataSegsOut */
+
+        __u64   tcpi_delivery_rate;
 };
 
 /* for TCP_MD5SIG socket option */
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 2250f891f931..f253e5019d22 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2712,7 +2712,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
 {
         const struct tcp_sock *tp = tcp_sk(sk); /* iff sk_type == SOCK_STREAM */
         const struct inet_connection_sock *icsk = inet_csk(sk);
-        u32 now = tcp_time_stamp;
+        u32 now = tcp_time_stamp, intv;
         unsigned int start;
         int notsent_bytes;
         u64 rate64;
@@ -2802,6 +2802,15 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
         info->tcpi_min_rtt = tcp_min_rtt(tp);
         info->tcpi_data_segs_in = tp->data_segs_in;
         info->tcpi_data_segs_out = tp->data_segs_out;
+
+        info->tcpi_delivery_rate_app_limited = tp->rate_app_limited ? 1 : 0;
+        rate = READ_ONCE(tp->rate_delivered);
+        intv = READ_ONCE(tp->rate_interval_us);
+        if (rate && intv) {
+                rate64 = (u64)rate * tp->mss_cache * USEC_PER_SEC;
+                do_div(rate64, intv);
+                put_unaligned(rate64, &info->tcpi_delivery_rate);
+        }
 }
 EXPORT_SYMBOL_GPL(tcp_get_info);
 
diff --git a/net/ipv4/tcp_rate.c b/net/ipv4/tcp_rate.c
index 52ff84be59ab..9be1581a5a08 100644
--- a/net/ipv4/tcp_rate.c
+++ b/net/ipv4/tcp_rate.c
@@ -149,12 +149,22 @@ void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost,
          * for connections suffer heavy or prolonged losses.
          */
         if (unlikely(rs->interval_us < tcp_min_rtt(tp))) {
-                rs->interval_us = -1;
                 if (!rs->is_retrans)
                         pr_debug("tcp rate: %ld %d %u %u %u\n",
                                  rs->interval_us, rs->delivered,
                                  inet_csk(sk)->icsk_ca_state,
                                  tp->rx_opt.sack_ok, tcp_min_rtt(tp));
+                rs->interval_us = -1;
+                return;
+        }
+
+        /* Record the last non-app-limited or the highest app-limited bw */
+        if (!rs->is_app_limited ||
+            ((u64)rs->delivered * tp->rate_interval_us >=
+             (u64)tp->rate_delivered * rs->interval_us)) {
+                tp->rate_delivered = rs->delivered;
+                tp->rate_interval_us = rs->interval_us;
+                tp->rate_app_limited = rs->is_app_limited;
         }
 }