Inaccurate system load plugin

[roger]

Hi all,

Since I'm not sure that the system load plugin is currently (actively) 
maintained - I haven't seen a new "official" release with the memswap.c fix 
that was proposed by a "normal" user several months ago - I'm using this 
general list instead of the xfce-goodies-dev one.

I'm afraid that there is some inaccuracy in the way cpu.c reports performance 
statistics, at least on Linux 2.6 systems.
Basically, the reported CPU usage (user, including nice, plus system) is 
overestimated since the elapsed time is underestimated, mainly due to the I/O 
wait time not being considered at all (this can be noticed when creating a 
big tar file).

Here is a cpu.c (http://rmlx.dyndns.org/misc/cpu.c), which I believe is more 
accurate on Linux 2.6 systems; for the code change, check the compilation key 
RS(=true).

Cheers,
Roger Seguin