iostat patch: Add dillon's systat changes to iostat

[Jan Lentfer]

Matthew Dillon schrieb:

    * Provide options for various modes, with the default being the old
      (KB/t, tps, MB/s) tuple, so the output can remain compact.
      I recommend one that does (tps, MBr/s, MBw/s).
Yeah, thought about that, too. Will look into it.

    * Maybe we can remove the tty statistics and add aggregate or
      primary interface network statistics.  Nobody cares about tty
      statistics any more but it would be kinda cool to see network
      stats there mixed with the disk stats.
Can I get that from devstat also? Well, could just look at systat 
-ifstat, right? How to determine the "primary" interface?

If you don't want to see tty (which I fully understand :-) ) you could 
just use iostat -dC.

    I am considering removing the tps/r, tps/w from systat -vm 1 and
    just having tps, but keeping MBs/r and MBs/w.  I think people will
    get more out of an aggregate tps stat.  Then for systat -vm 1
    we would have:  (KB/t, tps, MBs/r, MBs/w) (I should rename those to
    MBr/s and MBw/s I guess too).
Yep, Megabyte-seconds divided by writes (and reads) doesn't make a 
horrible lot of sense :-)

Jan