[plug] massive CPU activity on CD writing, cdda rips, etc

[Lawrie Abbott]

Craig Ringer wrote:

> Hi all
>
> I just got a nice new  ATA 48/24/48 CDRW drive, and I'm running into 
> an unexpected issue. I can't write at above 24x on my Athlon XP 1.5Ghz 
> machine due to the massive load it places on the CPU. Similar issues 
> are experienced using cdrecord, cdrdao, readcd, grip (w cdparanoia), 
> and other apps. The drive is configured as an IDE-SCSI device.
>
> I have the same problem on another box at work, so its not a 
> single-machine issue.
>
> Both are running Debian, sarge at home and woody at work. I've tried 
> the  woody 2.4 kernel and also run 2.4.20 (my build) as a matter of 
> course.
>
> Strangely, sometimes I'll do a CD write and it uses near zero CPU time 
> like you'd expect with DMA etc. This mainly ocurrs with simple writes 
> of .iso files from cdrecord in cooked mode. Using raw mode in cdrecord 
> or using cdrdao always places a massive load on the CPU.
>
> So ... this can't be right. I can't reliably write a CD at > 24x on a 
> modern fast machine. Anybody have any idea what's going on? My old 8x 
> burner wasn't a problem but that could be due to my failure to 
> actually notice the CPU load.
>
> I've heard things about issues with the IDE-SCSI interface but didn't 
> think it was anything quite this bad. OTOH I've also heard that big 
> improvements are due in 2.6 for ATA cdwriters.
>
> Anybody have any idea what's going on?
>
> Craig Ringer
>
>
>
This may be relevant, 
http://www.uwsg.iu.edu/hypermail/linux/kernel/0301.0/0987.html.

Lawrie