On Fri, 5 May 2000, Michael Robinton wrote:
> > > >
> > > > Not entirely, there is a fair bit more CPU overhead running an
> > > > IDE bus than a proper SCSI one.
> > >
> > > A "fair" bit on a 500mhz+ processor is really negligible.
> >
> >
> > Ehem, a fair bit on a 500Mhz CPU is ~ 30%. I have watched a
> > *single* UDMA66 drive (with read ahead, multiblock io, 32bit mode, and
> > dma transfers enabled) on a 2.2.14 + IDE + RAID patched take over 30%
> > of the CPU during disk activity. The same system with a 4 x 28G RAID0
> > set running would be < .1% idle during large copies. An exactly
> > configured system with UltraWide SCSI instead of IDE sits ~ 95% idle
> > during the same ops.
>
> Try turning on DMA
Ahem, try re-reading the above, line 3 first word!
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