Re: layout for top's CPU utilization display

["Greg A. Woods; Planix, Inc." <woods%planix.ca@localhost>]

On 12-May-08, at 7:14 AM, Tobias Nygren wrote:
> I guess eventually there will be more processors than lines on an  
> 80x24
> terminal. How do people feel about changing the above to something  
> like this?
>
>       user   nice    sys   intr   idle         user   nice    sys    
> intr   idle
> CPU0   0.0%   0.0%   0.0%   0.0%   100%  CPU4   0.0%   0.0%   0.0%    
> 0.0%   100%
> CPU1   0.0%   0.0%   0.0%   0.0%   100%  CPU5   0.0%   0.0%   0.0%    
> 0.0%   100%
> CPU2   0.0%   0.0%   0.0%   0.0%   100%  CPU6   0.0%   0.0%   0.0%    
> 0.0%   100%
> CPU3   0.0%   0.0%   0.0%   0.0%   100%  CPU7   0.0%   0.0%   0.0%    
> 0.0%   100%

I don't really like that layout -- one per line is best, if there must  
be one line per CPU.

Two points:

1. aspiring to fit useful information, especially about "large"  
systems, within an 80x24 display is not a useful or laudable goal in  
these days when mega-pixel displays are practically the minimum.  It's  
easy to get at least 50 lines with decent character size on even a  
small laptop display.  I'm not even sure it's worthwhile to try to  
write code to alternately support a compromised layout like that in  
case it is detected that the current screen size is too small.

2. the one per line layout really is much easier to read I think, i.e.  
for the eye to be able to see trends and patterns in the data.  Of  
course ideally a graphical representation is most useful for this  
purpose.

Anyway, beyond 4-6 lines it's not very likely that many of us can sum  
up the total utilization on every update, even if it is only once  
every 5 seconds.  A more dedicated, and hopefully more graphical,  
display would be best if the goal is to visualize individual CPU usage  
(say to verify the fairness of the scheduler and/or the achieved  
parallelism of the workload).  For the likes of 'top' and 'systat' it  
is probably best to just give the overall CPU utilization on one line.

--
                                        Greg A. Woods; Planix, Inc.
                                        <woods%planix.ca@localhost>