Re: Eradic disk access during reads

[Willy Tarreau <willy@w.ods.org>]

On Sun, Sep 18, 2005 at 07:02:17PM +0300, Denis Vlasenko wrote:
> > > My CPU is not that new:
> > 
> > PII - 400Mhz here.
> 
> I meant that kernel seem to eat too much CPU here. This
> is not expected. I expected CPU bar to be all D.

This is often caused by disks running in PIO instead of DMA.

> > Also, great meter!  Best of all does not hog the CPU!
> > Could you add a top3 procs display?
> 
> What is a "top3 procs display"?

probably something which will turn your tool into sort of a complex and
unusable one when another session running 'top' could do the trick.

Oh, BTW, the first reason I wrote my tool was to avoid copying into
/dev/null which consumes a small amount of CPU. Thus, I made it a pure
data eater. It might be interesting to run it instead of 'dd' while your
tool is running, to see if system usage decreases a bit.

Regards,
Willy