Re: 2.6.4 : 100% CPU use on EIDE disk operarion, VIA chipset

[Bill Davidsen]

Andreas Hartmann wrote:
> Bill Davidsen wrote:
>
> > Andreas Hartmann wrote:
> >
> > > This is what top says during cp of 512MB-file:
> > > Cpu(s):  2.0% us,  8.3% sy,  0.0% ni,  0.0% id, 89.0% wa,  0.7% hi,  
> > > 0.0% si
> > >
> > > New is "wa", what probably means "wait". This value is very high as 
> > > long as the HD is writing or reading datas:
> > >
> > > cp dummy /dev/null
> > > produces this top-line:
> > > Cpu(s):  3.0% us,  5.3% sy,  0.0% ni,  0.0% id, 91.0% wa,  0.7% hi,  
> > > 0.0% si
> >
> >
> > Yes "wa" is not intuitive, some other operating systems use "wio" for 
> > "wait i/o" time. As noted in the other thread, you can try the 
> > deadline elevator or increased readahead for your load.
>
>
> If the processor and the kernel could do other things during wa, like
> compiling e.g., it would be no problem. But it seems to be, that this is
> not possible. Or did I oversee something?

Yes, wio is similar to idle, processor is available for work even if 
disk access is running slowly.

--
bill davidsen <davidsen@xxxxxxx>
  CTO TMR Associates, Inc
  Doing interesting things with small computers since 1979
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