Subject: Re: FVWM: What does xgraph graph?

From: Woodchuck <[email-masked]>
Date: Tue, 14 May 2002 04:44:59 -0400 (EDT)

On Sun, 21 Apr 2002, Felix Karpfen wrote:

> Thank you for the prompt reply.
>
> That was one of my guesses.  However, apart from the unexplained sudden
> massive increases in (apparent) CPU usage - which remain unaffected by
> closing and reloading fvwm2 and only disappear on a reboot of the system
> - there appears to be little correlation with the graphed display and
> the output of top.

The display is of the "load factor", which is more or less the
number of "runnable" processes.  This is not *exactly* the same
as CPU load, since CPU load cannot exceed 100%;  load factor has
no real upper limit.  Moreover, the graph's display is a time-average
over a sample interval. (Every time it scrolls is one interval).

> It is a very trivial problem and does not appear to make the slightest
> difference on the way programs actually run.

Heh.  The genius of Unix.  This is probably because the programs
are IO bound.  I am currently compiling three kernels in parallel
on one machine, and its load factor is running around 5.5 to 6.
But the most top shows for any process is 2-3% cpu.  Compiling is
mostly IO work.  With good disks, you don't really notice a slow down
in things like keyboard response or process initialization.

(This discussion based on BSD, I dunno what Linux or Solaris do.)

When I want to see a high load factor, I simply fetch a bunch of mail
from a popserver.  The various sendmails are actually trivial tasks,
but they stay runnable for a long time doing dns lookups and so on.

> So if there is no obvious answer, please ignore.

For even more graphs, try fetching and installing xperfmon or
one of the other performance monitors.

Dave
-- 
         The man who reads nothing at all is better educated
	 than the man who reads nothing but newspapers.
                                  -- Thomas Jefferson

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