Linux Command

6. STUPID TRICKS Sampler

Many of these 'tricks' work best when you give top a scheduling boost. So plan on starting him with a nice value of -10, assuming you've got the authority.

6a. Kernel Magic

6b. Bouncing Windows

6c. The Big Bird Window

6a. Kernel Magic

For these stupid tricks, top needs full-screen mode.

• The user interface, through prompts and help, intentionally implies that the delay interval is limited to tenths of a second. However, you're free to set any desired delay. If you want to see Linux at his scheduling best, try a delay of .09 seconds or less.

  For this experiment, under x-windows open an xterm and maximize it. Then do the following:
  . provide a scheduling boost and tiny delay via:
  nice -n -10 top -d.09
  . keep sorted column highlighting Off to minimize
  path length
  . turn On reverse row highlighting for emphasis
  . try various sort columns (TIME/MEM work well),
  and normal or reverse sorts to bring the most
  active processes into view

  What you'll see is a very busy Linux doing what he's always done for you, but there was no program available to illustrate this.

• Under an xterm using 'white-on-black' colors, try setting top's task color to black and be sure that task highlighting is set to bold, not reverse. Then set the delay interval to around .3 seconds.

  After bringing the most active processes into view, what you'll see are the ghostly images of just the currently running tasks.

• Delete the existing rcfile, or create a new symlink. Start this new version then type 'T' (a secret key, see topic 3c. TASK Area Commands, Sorting) followed by 'W' and 'q'. Finally, restart the program with -d0 (zero delay).

  Your display will be refreshed at three times the rate of the former top, a 300% speed advantage. As top climbs the TIME ladder, be as patient as you can while speculating on whether or not top will ever reach the top.

6b. Bouncing Windows

For these stupid tricks, top needs alternate-display mode.

• With 3 or 4 task displays visible, pick any window other than the last and turn idle processes Off. Depending on where you applied 'i', sometimes several task displays are bouncing and sometimes it's like an accordion, as top tries his best to allocate space.

• Set each window's summary lines differently: one with no memory; another with no states; maybe one with nothing at all, just the message line. Then hold down 'a' or 'w' and watch a variation on bouncing windows -- hopping windows.

• Display all 4 windows and for each, in turn, set idle processes to Off. You've just entered the "extreme bounce" zone.

6c. The Big Bird Window

This stupid trick also requires alternate-display mode.

• Display all 4 windows and make sure that 1:Def is the 'current' window. Then, keep increasing window size until the all the other task displays are "pushed out of the nest".

  When they've all been displaced, toggle between all visible/invisible windows. Then ponder this:
  
  is top fibbing or telling honestly your imposed truth?

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