[geeks] Linux disparity

[Mike Meredith]

On Wednesday 18 December 2002 8:01 am, Joshua D Boyd wrote:
> Hey, on my linux machine, CPU meters register barely anything, yet I
> have a very high system load (over 2).  Anyone know why this might
> be? 

Do you mean the output of 'uptime' ? That's the average number of 
processes waiting in the run queue. And '2' is hardly very high ... 
I've seen Linux servers recover gracefully from states with load 
averages in the 50's.

'top' is a far better way of analysing what your system is doing at any 
one time. In particular look at the "system" percentage as that shows 
the amount of work being done by the kernel rather than user processes 
... which might be relevant here.

> I'm doing a fair amount of network copying in the background, but
> nothing heavy over an SSH link.  Is it perhaps being caused by a 3COM
> PCI ethernet card?  I seem to remeber people dissing them here.

I don't remember it coming up here, but nobody I work with would stick a 
3com network card into a server because of the load they are rumoured 
to put onto the CPU.

The most important metric of performance is does the box feel slow ? If 
it doesn't then it isn't worth trying to chase down what is causing the 
problem (except out of curiosity).

BTW: Has anyone got any really good references for performance analysis 
?