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SubjectRe: PROMBLEM: CD burning at 16x uses excessive CPU, although DMA is enabled
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I'm not completely sure about burning audio, but linux doesn't read
audio cds using DMA. It just wont on ide devices. You can use a patch
that allows this from andrew morton. I dont write many audio cds so
I've never tested it's effect on writing a cd, only reading. I imagine
it's not safe to use dma on raw/audio cds. but go check it out
anyways.


On Mon, 2002-04-08 at 10:54, Bill Davidsen wrote:
> On Mon, 8 Apr 2002, Anssi Saari wrote:
>
> > [1.] One line summary of the problem:
> > CD burning at 16x uses excessive CPU, although DMA is enabled
>
> That's a hint things are not working as you expect...
>
> > [2.] Full description of the problem/report:
> > My system seems to use a lot of CPU time when writing CDs at 16x. The
> > system is unable to feed the burning software's buffer fast enough when
> > burning software (cdrecord 1.11a20, cdrdao 1.1.5) is run as normal user.
> > If run as root, system is almost unresponsive during the burn.
>
> With all the information you provided, you have totally not quatified
> how much CPU you find "excessive." I would not be surprised to see 10-15%
> of the CPU, virtually all in system time, as a normal burn of an ISO
> image. If the time is in user mode with other image types, it may well be
> that you are doing something which actually requires a lot of CPU (byte
> swapping or some such).
>
> Going from a disk to a CD using DMA on both should not take much
> *system* CPU, even if these are ATAPI (assuming they are not on the same
> cable).
>
> --
> bill davidsen <davidsen@tmr.com>
> CTO, TMR Associates, Inc
> Doing interesting things with little computers since 1979.
>
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