top(1) annoyances

Chris Turner c.turner at
Fri Feb 4 01:53:59 PST 2011

Chris Turner wrote:
top's "this terminal can only display N processes"
gets on my nerves.
Ok - so the top(1) saga continues.

Digging around, and meditating on it a bit,
the following is clear -
1) top was made when fast computers were slow
2) top was made for serial terminals

So - some assumptions for that:

1) scanning the process table is slow.
2) redrawing the terminal is slow

1) only rewrite the needed / changed lines to the
2) Keeping #1 in mind, don't display more than the terminal
   can display, else the terminal become an endlessly
   scrolling nightmare of uninterruptable top output
   (kind of like running 'find / |xargs cat' on a 9600 baud vax tty)
3) The number of processes displayed w/r/t the screen is important
4) And only display what is needed / asked for.
as a result:

1) top does not display more than the default number of processes
   unless requested to do so.
   Someone had asked this previously - to show more, run e.g:

   top 100

   DOH! arty-effem! silly me.

   it is the 'show the top N programs program' not 'fill my screen
   with program stuff program'. Like the top-10 Radio Countdown WOOHOO.
   With Casey Casem.

   or you can fill the screen with program stuff by running 'top -a'

   or if you prefer apropos to man -k : by running 'top all'.

2) top will provide a highly annoying warning when not able to
   view the expected number of processes
in conclusion, I suggest:

1) re-enabling the annoying top warning message, and perhaps choosing
   a sensible default to prevent the annoying warning on a handy-dandy
   default punched-card sized 80x24 display
this would mean changing DEFAULT_TOPN in /usr/src/usr.bin/top/config.h
to 17. (24 - 7 for the 'header' stuff)


- Chris

p.s: did you know you can setup TOPCOLORS to configure colorful
alert thresholds as well? nifty.

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