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From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
To:     linux-bluetooth@vger.kernel.org
Subject: [BlueZ PATCH v2] monitor: Use gnuplot to plot graph of Latency-Packets
Date:   Thu, 27 Jul 2023 11:37:17 -0700
Message-ID: <20230727183717.1026331-1-luiz.dentz@gmail.com>
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From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This make use of gnuplot when using -a/--analyze to plot a graph of
Latency-Packets:

  Found BR-ACL connection with handle 256
        Address: XX:XX:XX:XX:XX:XX (Sony Home Entertainment&Sound Products Inc)
        60 RX packets
        22548 TX packets
        22547 TX completed packets
        3 msec min latency
        73 msec max latency
        11 msec median latency
        6 octets TX min packet size
        850 octets TX max packet size
        847 octets TX median packet size

  7000 +-------------------------------------------------------------------+
       |        +       +        +       +        +       +        +       |
       |        +                                          Packets +-----+ |
  6000 |-+     +|                                                        +-|
       |       ||                                                          |
  5000 |-+     ||                                                        +-|
       |       ||                                                          |
       |       ||                                                          |
  4000 |-+     ||                                                        +-|
       |       ||                                                          |
       |       ||                                                          |
  3000 |-+     |+                                                        +-|
       |       ||                                                          |
       |       ||                                                          |
  2000 |-+     ||                                                        +-|
       |      +||                                                          |
  1000 |-+    |||++                                                      +-|
       |      |||||+ +                                                     |
       |      ||||||+|+++        +       +        +       +        +       |
     0 +-------------------------------------------------------------------+
       0        10      20       30      40       50      60       70      80
                                   Latency (ms)
---
 monitor/analyze.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)

diff --git a/monitor/analyze.c b/monitor/analyze.c
index a20ba98b0be4..c7c274fb25fe 100644
--- a/monitor/analyze.c
+++ b/monitor/analyze.c
@@ -17,6 +17,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <sys/time.h>
+#include <unistd.h>
 
 #include "lib/bluetooth.h"
 
@@ -28,6 +29,9 @@
 #include "monitor/packet.h"
 #include "monitor/analyze.h"
 
+#define TIMEVAL_MSEC(_tv) \
+	(long long)((_tv)->tv_sec * 1000 + (_tv)->tv_usec / 1000)
+
 struct hci_dev {
 	uint16_t index;
 	uint8_t type;
@@ -69,12 +73,18 @@ struct hci_conn {
 	struct timeval tx_lat_min;
 	struct timeval tx_lat_max;
 	struct timeval tx_lat_med;
+	struct queue *plot;
 	uint16_t tx_pkt_min;
 	uint16_t tx_pkt_max;
 	uint16_t tx_pkt_med;
 	struct queue *chan_list;
 };
 
+struct conn_plot {
+	long long x_msec;
+	size_t y_count;
+};
+
 struct l2cap_chan {
 	uint16_t cid;
 	uint16_t psm;
@@ -135,6 +145,44 @@ static struct l2cap_chan *chan_lookup(struct hci_conn *conn, uint16_t cid,
 	return chan;
 }
 
+static void tmp_write(void *data, void *user_data)
+{
+	struct conn_plot *plot = data;
+	FILE *tmp = user_data;
+
+	fprintf(tmp, "%lld %zu\n", plot->x_msec, plot->y_count);
+}
+
+static void conn_plot_draw(struct hci_conn *conn)
+{
+	const char *filename = "analyze.tmp";
+	FILE *gplot = popen("gnuplot", "w");
+	FILE *tmp;
+
+	if (!gplot)
+		return;
+
+	if (queue_isempty(conn->plot))
+		goto done;
+
+	tmp = fopen(filename, "w");
+	if (!tmp)
+		goto done;
+
+	queue_foreach(conn->plot, tmp_write, tmp);
+
+	fprintf(gplot, "set terminal dumb enhanced ansi\n");
+	fprintf(gplot, "set xlabel 'Latency (ms)'\n");
+	fprintf(gplot, "plot './%s' using 1:2 t 'Packets' w impulses\n",
+								filename);
+	fflush(gplot);
+
+	fclose(tmp);
+done:
+	pclose(gplot);
+	unlink(filename);
+}
+
 static void conn_destroy(void *data)
 {
 	struct hci_conn *conn = data;
@@ -187,6 +235,10 @@ static void conn_destroy(void *data)
 	print_field("%u octets TX min packet size", conn->tx_pkt_min);
 	print_field("%u octets TX max packet size", conn->tx_pkt_max);
 	print_field("%u octets TX median packet size", conn->tx_pkt_med);
+
+	conn_plot_draw(conn);
+
+	queue_destroy(conn->plot, free);
 	queue_destroy(conn->chan_list, chan_destroy);
 
 	queue_destroy(conn->tx_queue, free);
@@ -447,6 +499,35 @@ static void evt_cmd_complete(struct hci_dev *dev, struct timeval *tv,
 	}
 }
 
+static bool match_plot_latency(const void *data, const void *user_data)
+{
+	const struct conn_plot *plot = data;
+	const struct timeval *latency = user_data;
+
+	return TIMEVAL_MSEC(latency) == plot->x_msec;
+}
+
+static void conn_plot_add(struct hci_conn *conn, struct timeval *latency,
+						uint16_t count)
+{
+	struct conn_plot *plot;
+
+	plot = queue_find(conn->plot, match_plot_latency, latency);
+	if (plot) {
+		plot->y_count += count;
+		return;
+	}
+
+	if (!conn->plot)
+		conn->plot = queue_new();
+
+	plot = new0(struct conn_plot, 1);
+	plot->x_msec = TIMEVAL_MSEC(latency);
+	plot->y_count = count;
+
+	queue_push_tail(conn->plot, plot);
+}
+
 static void evt_num_completed_packets(struct hci_dev *dev, struct timeval *tv,
 					const void *data, uint16_t size)
 {
@@ -504,6 +585,8 @@ static void evt_num_completed_packets(struct hci_dev *dev, struct timeval *tv,
 			} else
 				conn->tx_lat_med = res;
 
+			conn_plot_add(conn, &res, count);
+
 			free(last_tx);
 		}
 	}
-- 
2.41.0