ss: print new tcp_info fields: busy, rwnd-limited, sndbuf-limited times

Dump some new fields added to tcp_info in v4.10: tcpi_busy_time,
tcpi_rwnd_limited, tcpi_sndbuf_limited.

Example output for a flow busy for 110ms but never measurably limited by
receive window or send buffer:
   busy:110ms

Example output for a flow usually limited by receive window:
   busy:111ms rwnd_limited:101ms(91.0%)

Example output for a flow sometimes limited by send buffer:
   busy:50ms sndbuf_limited:10ms(20.0%)

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>

diff --git a/misc/ss.c b/misc/ss.c
index 7f039859f09632ed955b564a9b2f7770118beeb4..839781ee29bc94266b70ec5be27e0a13a8a4f37e 100644 (file)
--- a/misc/ss.c
+++ b/misc/ss.c
@@ -817,6 +817,9 @@ struct tcpstat {
        double              rcv_rtt;
        double              min_rtt;
        int                 rcv_space;
+       unsigned long long  busy_time;
+       unsigned long long  rwnd_limited;
+       unsigned long long  sndbuf_limited;
        bool                has_ts_opt;
        bool                has_sack_opt;
        bool                has_ecn_opt;
@@ -1980,6 +1983,18 @@ static void tcp_stats_print(struct tcpstat *s)
        if (s->app_limited)
                printf(" app_limited");
 
+       if (s->busy_time) {
+               printf(" busy:%llums", s->busy_time / 1000);
+               if (s->rwnd_limited)
+                       printf(" rwnd_limited:%llums(%.1f%%)",
+                              s->rwnd_limited / 1000,
+                              100.0 * s->rwnd_limited / s->busy_time);
+               if (s->sndbuf_limited)
+                       printf(" sndbuf_limited:%llums(%.1f%%)",
+                              s->sndbuf_limited / 1000,
+                              100.0 * s->sndbuf_limited / s->busy_time);
+       }
+
        if (s->unacked)
                printf(" unacked:%u", s->unacked);
        if (s->retrans || s->retrans_total)
@@ -2283,6 +2298,9 @@ static void tcp_show_info(const struct nlmsghdr *nlh, struct inet_diag_msg *r,
                        s.min_rtt = (double) info->tcpi_min_rtt / 1000;
                s.delivery_rate = info->tcpi_delivery_rate * 8.;
                s.app_limited = info->tcpi_delivery_rate_app_limited;
+               s.busy_time = info->tcpi_busy_time;
+               s.rwnd_limited = info->tcpi_rwnd_limited;
+               s.sndbuf_limited = info->tcpi_sndbuf_limited;
                tcp_stats_print(&s);
                free(s.dctcp);
                free(s.bbr_info);