can we afford an extra column in iostat?

[Giorgos Keramidas]

While converting my laptop's main disk to zfs, I noticed iostat output
like this (bits copied from here and there):

| keramida at kobe:/home/keramida$ iostat -w3 ad0 da0
|       tty             ad0              da0             cpu
|  tin tout  KB/t tps  MB/s   KB/t tps  MB/s  us ni sy in id
|    5 2119 36.29  56  2.00  54.95   7  0.35   3  0  8  0 89
|    0 9478 10.90 290  3.09  57.22  12  0.67  42  0 43  0 15
|    012595  1.72 213  0.36  21.36  80  1.66  48  0 48  0  4
|    050042  4.56 715  3.19  11.44 164  1.83  29  0 50  1 20
|  11529568  7.34 443  3.17  16.97 165  2.74  31  0 53  0 16
|  33835534  7.61 211  1.57   7.31 295  2.11  36  0 55  1  9
|  38636874  3.10 186  0.56   6.63 309  2.00  37  0 56  0  7
|  24239726  2.54 196  0.49   6.13 336  2.01  36  0 56  0  8
|  17136654  0.57 192  0.11   7.97 305  2.37  34  0 56  0  9
|  23439020  0.76 195  0.15   7.02 333  2.28  32  0 57  1 11
|  43733189  2.52 192  0.47   6.99 269  1.84  37  0 57  1  5
|  36232178  5.48 193  1.03   6.78 268  1.77  38  0 54  0  8
|  43226266 34.19 228  7.61   6.94 253  1.72  32  0 49  1 19

The default output of iostat, when no disks are specified is a bit wider
than this, reaching column 75 here:

         1         2         3         4         5         6         7
12345678901234567890123456789012345678901234567890123456789012345678901234567890
---------------------------------------------------------------------------
      tty             ad0              md0              da0             cpu
 tin tout  KB/t tps  MB/s   KB/t tps  MB/s   KB/t tps  MB/s  us ni sy in id
   6 2315 34.97  58  1.99   6.46   0  0.00  47.41   8  0.37   4  0  8  0 88

But there's still a bit of space before column 80, so can we afford an
extra space between tin/tout to make the output look more like this?

| $ ./iostat -w2
|       tty             ad0              md0              da0             cpu
|  tin  tout  KB/t tps  MB/s   KB/t tps  MB/s   KB/t tps  MB/s  us ni sy in id
|    7  2570 32.92  62  1.98   6.46   0  0.00  43.44  10  0.41   4  0  9  0 87
|    0 36506  0.99 507  0.49   0.00   0  0.00  20.13 155  3.04  34  0 56  1  9
|    0 16695  0.83 226  0.18   0.00   0  0.00  26.16  97  2.48  35  0 56  0  9
|    0 24158 10.63 428  4.45   0.00   0  0.00  14.44 137  1.93  32  0 51  0 17
| ^C

The patch that changes this is quite small:

%%%
diff -r 0f182a7399e8 usr.sbin/iostat/iostat.c
--- a/usr.sbin/iostat/iostat.c	Sun Jul 12 09:34:48 2009 +0300
+++ b/usr.sbin/iostat/iostat.c	Tue Jul 14 07:20:41 2009 +0300
@@ -586,7 +586,7 @@
 		}
 
 		if (xflag == 0 && Tflag > 0)
-			printf("%4.0Lf%5.0Lf", cur.tk_nin / etime,
+			printf("%4.0Lf %5.0Lf", cur.tk_nin / etime,
 			    cur.tk_nout / etime);
 
 		devstats(hflag, etime, havelast);
@@ -696,7 +696,7 @@
 		(void)printf("\n");
 
 	if (Tflag > 0)
-		(void)printf(" tin tout");
+		(void)printf(" tin  tout");
 
 	for (i=0, printed = 0;(i < num_devices) && (printed < maxshowdevs);i++){
 		if ((dev_select[i].selected != 0)
@@ -754,7 +754,7 @@
 		"device     r/i   w/i    kr/i    kw/i wait svc_t  %%b  "
 			    );
 		if (Tflag > 0)
-			printf("tin tout ");
+			printf("tin  tout ");
 		if (Cflag > 0)
 			printf("us ni sy in id ");
 		printf("\n");
@@ -895,7 +895,7 @@
 		 */
 		printf("%52s","");
 		if (Tflag > 0)
-			printf("%4.0Lf%5.0Lf", cur.tk_nin / etime,
+			printf("%4.0Lf %5.0Lf", cur.tk_nin / etime,
 			    cur.tk_nout / etime);
 		if (Cflag > 0)
 			cpustats();
%%%