Re: 2.6.x Scheduler, preemption and responsiveness - puzzlement

[Con Kolivas]

Sid Boyce writes:

> Nuno Monteiro wrote:
>
> > On 2004.07.11 23:55, Sid Boyce wrote:
> >
> > > I've been wondering why this is, I can't remember what the BIOS says  
> > > about the hard drives, from memory it looked OK, I think it was set to
> >
> >
> > <snip snip>
> >
> > > PCI           IDE              nVidia Corporation nForce2 IDE (rev a2)
> >
> >
> > <snip snip>
> >
> > > # CONFIG_BLK_DEV_AMD74XX is not set
> >
> >
> > You don't have the driver for your IDE chipset compiled in. In the 
> > "ATA/ ATAPI/MFM/RLL support" under "Device Drivers" menu select "AMD 
> > and nVidia  IDE support". Also, you can disable the "Generic PCI IDE 
> > Chipset Support"  and the "VIA82CXXX chipset support" you seem to have 
> > enabled.
> >
> > Then you should be able to do DMA, and things will go a lot faster.
> >
> >
> > Hope this helps.
> >
> >
> >
> >         Nuno
>
> Oops!, thanks. The previous motherboard used the VIA chipset, so that 
> got missed when I changed over.
> Regards
> Sid.

DMA disabled is perhaps the most common reason for poor performance under 
I/O loads. I think some cut down configurations that people have used from 
their 2.4 installations have missed the appropriate IDE driver.

Cheers,
Con

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