can-utils: AOSP build clean up

[sojka/can-utils.git] / canbusload.c

diff --git a/canbusload.c b/canbusload.c
index 36f3423e0aca9f24d6e7883c9e6fced729532d3d..a5fb553b7dab2ec03ac705a1439b407de452aa6f 100644 (file)
--- a/canbusload.c
+++ b/canbusload.c
@@ -1,7 +1,3 @@
-/*
- *  $Id$
- */
-
 /*
  * canbusload.c
  *
@@ -41,7 +37,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
  * DAMAGE.
  *
- * Send feedback to <socketcan-users@lists.berlios.de>
+ * Send feedback to <linux-can@vger.kernel.org>
  *
  */
 
@@ -88,6 +84,7 @@ static unsigned char redraw;
 static unsigned char timestamp;
 static unsigned char color;
 static unsigned char bargraph;
+static unsigned char ignore_bitstuffing;
 static char *prg;
 
 void print_usage(char *prg)
@@ -98,20 +95,22 @@ void print_usage(char *prg)
        fprintf(stderr, "         -c (colorize lines)\n");
        fprintf(stderr, "         -b (show bargraph in %d%% resolution)\n", PERCENTRES);
        fprintf(stderr, "         -r (redraw the terminal - similar to top)\n");
+       fprintf(stderr, "         -i (ignore bitstuffing estimation in bandwith calculation)\n");
        fprintf(stderr, "\n");
        fprintf(stderr, "Up to %d CAN interfaces with mandatory bitrate can be specified on the \n", MAXSOCK);
        fprintf(stderr, "commandline in the form: <ifname>@<bitrate>\n\n");
        fprintf(stderr, "The bitrate is mandatory as it is needed to know the CAN bus bitrate to\n");
        fprintf(stderr, "calcultate the bus load percentage based on the received CAN frames.\n");
+       fprintf(stderr, "Due to the bitstuffing estimation the calculated busload may exceed 100%%.\n");
        fprintf(stderr, "For each given interface the data is presented in one line which contains:\n\n");
        fprintf(stderr, "(interface) (received CAN frames) (used bits total) (used bits for payload)\n");
        fprintf(stderr, "\nExample:\n");
        fprintf(stderr, "\nuser$> canbusload can0@100000 can1@500000 can2@500000 can3@500000 -r -t -b -c\n\n");
        fprintf(stderr, "%s 2008-05-27 15:18:49\n", prg);
-       fprintf(stderr, " can0@100000  805  74491  36656  74%%  |XXXXXXXXXXXXXX......|\n");
-       fprintf(stderr, " can1@500000  796  75140  37728  15%%  |XXX.................|\n");
-       fprintf(stderr, " can2@500000    0      0      0   0%%  |....................|\n");
-       fprintf(stderr, " can3@500000   47   4633   2424   0%%  |....................|\n");
+       fprintf(stderr, " can0@100000   805   74491  36656  74%% |XXXXXXXXXXXXXX......|\n");
+       fprintf(stderr, " can1@500000   796   75140  37728  15%% |XXX.................|\n");
+       fprintf(stderr, " can2@500000     0       0      0   0%% |....................|\n");
+       fprintf(stderr, " can3@500000    47    4633   2424   0%% |....................|\n");
        fprintf(stderr, "\n");
 }
 
@@ -162,7 +161,7 @@ void printstats(int signo)
                else
                        percent = 0;
 
-               printf(" %*s@%-*d %4d %6d %6d %3d%%",
+               printf(" %*s@%-*d %5d %7d %6d %3d%%",
                       max_devname_len, stat[i].devname,
                       max_bitrate_len, stat[i].bitrate,
                       stat[i].recv_frames,
@@ -172,7 +171,10 @@ void printstats(int signo)
 
                if (bargraph) {
 
-                       printf("  |");
+                       printf(" |");
+
+                       if (percent > 100)
+                               percent = 100;
 
                        for (j=0; j < NUMBAR; j++){
                                if (j < percent/PERCENTRES)
@@ -195,6 +197,7 @@ void printstats(int signo)
        }
 
        printf("\n");
+       fflush(stdout);
 
        alarm(1);
 }
@@ -220,7 +223,7 @@ int main(int argc, char **argv)
 
        prg = basename(argv[0]);
 
-       while ((opt = getopt(argc, argv, "rtbch?")) != -1) {
+       while ((opt = getopt(argc, argv, "rtbcih?")) != -1) {
                switch (opt) {
                case 'r':
                        redraw = 1;
@@ -238,6 +241,10 @@ int main(int argc, char **argv)
                        color = 1;
                        break;
 
+               case 'i':
+                       ignore_bitstuffing = 1;
+                       break;
+
                default:
                        print_usage(prg);
                        exit(1);
@@ -365,11 +372,32 @@ int main(int argc, char **argv)
 
                                stat[i].recv_frames++;
                                stat[i].recv_bits_payload += frame.can_dlc*8;
-                               stat[i].recv_bits_total += frame.can_dlc*8;
-                               if (frame.can_id & CAN_EFF_FLAG)
-                                       stat[i].recv_bits_total += 67;
-                               else
-                                       stat[i].recv_bits_total += 47;
+
+                               /*
+                                * Following Ken Tindells *worst* case calculation for stuff-bits
+                                * (see "Guaranteeing Message Latencies on Controller Area Network" 1st ICC'94)
+                                * the needed bits on the wire can be calculated as:
+                                *
+                                * (34 + 8n)/5 + 47 + 8n for SFF frames (11 bit CAN-ID) => (269 + 48n)/5 
+                                * (54 + 8n)/5 + 67 + 8n for EFF frames (29 bit CAN-ID) => (389 + 48n)/5 
+                                *
+                                * while 'n' is the data length code (number of payload bytes)
+                                *
+                                */
+
+                               if (ignore_bitstuffing) {
+                                       /* calculation without bitstuffing */
+                                       if (frame.can_id & CAN_EFF_FLAG)
+                                               stat[i].recv_bits_total += 67 + frame.can_dlc*8;
+                                       else
+                                               stat[i].recv_bits_total += 47 + frame.can_dlc*8;
+                               } else {
+                                       /* needed bits including estimated worst case stuff bits */
+                                       if (frame.can_id & CAN_EFF_FLAG)
+                                               stat[i].recv_bits_total += (389 + frame.can_dlc*48)/5;
+                                       else
+                                               stat[i].recv_bits_total += (269 + frame.can_dlc*48)/5;
+                               }
                        }
                }
        }