[MPlayer-users] mplayer and preemptible kernel

[Nyk Tarr]

On Tue, Oct 29, 2002 at 11:45:19PM +0000, Nyk Tarr wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> On Tue, Oct 29, 2002 at 11:52:42PM +0100, Jindrich Makovicka wrote:
> > [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> > Jeremy Brenner wrote:
> > 
> > >[Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> > >
> > > 
> > >
> > >>>From what I read on the linux kernel mailing list, ide-scsi does not
> > >>support dma. I suspect it never will as the only things that use it
> > >>(programs that need direct access to cd-rom/cd-rw etc. hardware) will
> > >>have a new interface to use in the next stable release. Oh, and the new
> > >>IDE code (>2.5.somethingorother) can have both ide-cd and ide-scsi
> > >>loaded for the same device.
> > >>
> > >
> > >wow... thats great... my cpu usage when burning or ripping at 40x is
> > >ludicrous.  I almost payed another 100$ for the scsi version because of
> > >this.  Its sad that a windows install would actually perform better
> > >burning cds than my gentoo install.
> > >
> > I just tried hdparm -d 0 & hdparm -d 1 on /dev/cdrom and the CPU usage 
> > is 7% with DMA and 70% without.
> > Using vanilla 2.4.19, scsi emulation on all CD drives.
> 
> Looks like I completely misunderstood. Obviously DMA /is/ relevent...
> 
> Sorry.


Bad form, I know, but...

After further investigation...
cdrecord does indeed use ide-scsi, or rather the sg interface.
ide-scsi does support DMA, but not for the reading and writing of audio
tracks.
see
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&selm=1033330079.14029.6.camel%40irongate.swansea.linux.org.uk

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