Report number of reorder_seen

TCP can detect reordering by tracking SACKs and timestamps
coming back to the sender. This is useful information for
investigating performance issues and testing networks as
good networks should generally not reorder packets.

Author: kuba-moo

src/iperf.h

@@ -110,6 +110,7 @@ struct iperf_interval_results
     int rtt;
     int rttvar;
     int pmtu;
+    int reorder;
 };
 
 struct iperf_stream_result
@@ -121,6 +122,7 @@ struct iperf_stream_result
     iperf_size_t bytes_sent_omit;
     int stream_prev_total_retrans;
     int stream_retrans;
+    int stream_reorder;
     int stream_prev_total_sacks;
     int stream_sacks;
     int stream_max_rtt;

src/iperf_api.c

@@ -3185,6 +3185,8 @@ iperf_stats_callback(struct iperf_test *test)
 
 		    temp.rttvar = get_rttvar(&temp);
 		    temp.pmtu = get_pmtu(&temp);
+		    temp.reorder = get_reorder(&temp);
+		    rp->stream_reorder = temp.reorder;
 		}
 	    }
 	} else {
@@ -3623,7 +3625,7 @@ iperf_print_results(struct iperf_test *test)
                     if (test->sender_has_retransmits) {
                         /* Sender summary, TCP and SCTP with retransmits. */
                         if (test->json_output)
-                            cJSON_AddItemToObject(json_summary_stream, "sender", iperf_json_printf("socket: %d  start: %f  end: %f  seconds: %f  bytes: %d  bits_per_second: %f  retransmits: %d  max_snd_cwnd:  %d  max_snd_wnd:  %d  max_rtt:  %d  min_rtt:  %d  mean_rtt:  %d sender: %b", (int64_t) sp->socket, (double) start_time, (double) sender_time, (double) sender_time, (int64_t) bytes_sent, bandwidth * 8, (int64_t) sp->result->stream_retrans, (int64_t) sp->result->stream_max_snd_cwnd, (int64_t) sp->result->stream_max_snd_wnd, (int64_t) sp->result->stream_max_rtt, (int64_t) sp->result->stream_min_rtt, (int64_t) ((sp->result->stream_count_rtt == 0) ? 0 : sp->result->stream_sum_rtt / sp->result->stream_count_rtt), stream_must_be_sender));
+                            cJSON_AddItemToObject(json_summary_stream, "sender", iperf_json_printf("socket: %d  start: %f  end: %f  seconds: %f  bytes: %d  bits_per_second: %f  retransmits: %d  reorder:  %d  max_snd_cwnd:  %d  max_snd_wnd:  %d  max_rtt:  %d  min_rtt:  %d  mean_rtt:  %d sender: %b", (int64_t) sp->socket, (double) start_time, (double) sender_time, (double) sender_time, (int64_t) bytes_sent, bandwidth * 8, (int64_t) sp->result->stream_retrans, (int64_t) sp->result->stream_reorder, (int64_t) sp->result->stream_max_snd_cwnd, (int64_t) sp->result->stream_max_snd_wnd, (int64_t) sp->result->stream_max_rtt, (int64_t) sp->result->stream_min_rtt, (int64_t) ((sp->result->stream_count_rtt == 0) ? 0 : sp->result->stream_sum_rtt / sp->result->stream_count_rtt), stream_must_be_sender));
                         else
                             if (test->role == 's' && !sp->sender) {
                                 if (test->verbose)
@@ -4070,7 +4072,7 @@ print_interval_results(struct iperf_test *test, struct iperf_stream *sp, cJSON *
 	if (test->sender_has_retransmits == 1 && sp->sender) {
 	    /* Interval, TCP with retransmits. */
 	    if (test->json_output)
-		cJSON_AddItemToArray(json_interval_streams, iperf_json_printf("socket: %d  start: %f  end: %f  seconds: %f  bytes: %d  bits_per_second: %f  retransmits: %d  snd_cwnd:  %d  snd_wnd:  %d  rtt:  %d  rttvar: %d  pmtu: %d  omitted: %b sender: %b", (int64_t) sp->socket, (double) st, (double) et, (double) irp->interval_duration, (int64_t) irp->bytes_transferred, bandwidth * 8, (int64_t) irp->interval_retrans, (int64_t) irp->snd_cwnd, (int64_t) irp->snd_wnd, (int64_t) irp->rtt, (int64_t) irp->rttvar, (int64_t) irp->pmtu, irp->omitted, sp->sender));
+		cJSON_AddItemToArray(json_interval_streams, iperf_json_printf("socket: %d  start: %f  end: %f  seconds: %f  bytes: %d  bits_per_second: %f  retransmits: %d  snd_cwnd:  %d  snd_wnd:  %d  rtt:  %d  rttvar: %d  pmtu: %d  reorder: %d  omitted: %b sender: %b", (int64_t) sp->socket, (double) st, (double) et, (double) irp->interval_duration, (int64_t) irp->bytes_transferred, bandwidth * 8, (int64_t) irp->interval_retrans, (int64_t) irp->snd_cwnd, (int64_t) irp->snd_wnd, (int64_t) irp->rtt, (int64_t) irp->rttvar, (int64_t) irp->pmtu, (int64_t) irp->reorder, irp->omitted, sp->sender));
 	    else {
 		unit_snprintf(cbuf, UNIT_LEN, irp->snd_cwnd, 'A');
 		iperf_printf(test, report_bw_retrans_cwnd_format, sp->socket, mbuf, st, et, ubuf, nbuf, irp->interval_retrans, cbuf, irp->omitted?report_omitted:"");

src/iperf_api.h

@@ -285,6 +285,7 @@ long get_snd_wnd(struct iperf_interval_results *irp);
 long get_rtt(struct iperf_interval_results *irp);
 long get_rttvar(struct iperf_interval_results *irp);
 long get_pmtu(struct iperf_interval_results *irp);
+long get_reorder(struct iperf_interval_results *irp);
 void print_tcpinfo(struct iperf_test *test);
 void build_tcpinfo_message(struct iperf_interval_results *r, char *message);
 

src/tcp_info.c

@@ -213,6 +213,20 @@ get_pmtu(struct iperf_interval_results *irp)
 #endif
 }
 
+/*************************************************************/
+/*
+ * Return number of reordering events seen.
+ */
+long
+get_reorder(struct iperf_interval_results *irp)
+{
+#if defined(linux) && defined(TCP_REPAIR_ON)
+    return irp->tcpInfo.tcpi_reord_seen;
+#else
+    return -1;
+#endif
+}
+
 /*************************************************************/
 void
 build_tcpinfo_message(struct iperf_interval_results *r, char *message)