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DragonFly kernel List (threaded) for 2011-02
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Re: top(1) annoyances

From: Chris Turner <c.turner@xxxxxxxxxxxxxxxxxxx>
Date: Fri, 04 Feb 2011 03:50:02 -0600

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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