Re: PROMBLEM: CD burning at 16x uses excessive CPU, although DMA is enabled

Anssi Saari (as@sci.fi)
Sun, 14 Apr 2002 15:39:35 +0300


On Tue, Apr 09, 2002 at 01:27:48PM -0700, Andre Hedrick wrote:
> On Tue, 9 Apr 2002, Roger Larsson wrote:
>
> > On tisdagen den 9 april 2002 12.01, Anssi Saari wrote:
> > > On Mon, Apr 08, 2002 at 06:02:55PM -0400, Mark Hahn wrote:
> > > > I think someone else already pointed out that doing
> > > > a kernel profile would be good. strace would also
> > > > be quite useful, even just the -c form.
> > >
> > > Here it is:
> > >
> > > With unmaskirq=1 first:
> > >
> > >
> > > 49 handle_IRQ_event 0.5104
> > > 239 file_read_actor 2.4896
> > > 3324 default_idle 69.2500
> > > 20097 ide_output_data 104.6719
> >
> > Hey, what is this?
> >
> > Comment of the function is:
> > "This is used for most PIO data transfers *to* the IDE interface"
> > (see /drivers/ide/ide.c:426)
> > Has it reverted to PIO mode?
>
> This is because there are not a proper and correct state diagram data
> handler set for ATAPI, period. Initially the driver evolved out of PIO
> calls to the PACKET_COMMAND opcode for the ATA command set. Since there
> has been zero updates/attempts to create a proper ATAPI/ASPI by anyone,
> you can expect PIO transactions.

I have now tried the writer on an old Pentium motherboard with Intel
430HX chipset and PIIX3. The performance problems didn't happen there,
so I would guess this is more a problem with how Linux handles the VIA
686b southbridge.

But what can I do to help fix this problem?

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