[vorbis] cdparanoia mailing list ?

[Segher Boessenkool]

> data
>  with dma
> hdparm -t /dev/cdrom
> /dev/cdrom:
>  Timing buffered disk reads:  64 MB in 10.04 seconds =  6.37 MB/sec
> 
> without dma (pio mode 4)
> hdparm -t /dev/cdrom
> /dev/cdrom:
>  Timing buffered disk reads:  64 MB in 32.17 seconds =  1.99 MB/sec
>   (and that's with 100% cpu usage)

Your hdd or IDE chipset has a maximum PIO mode that is slower than its
maximum DMA mode.

> Without dma caused the system to crawl and cpu to hit 100% (that's
> increasing heat and slows everything else down)

The fact it is increasing heat is a cpu design problem.  It's a shame
if a cou gets that hot when all it's doing is busy waiting on i/o.

> This discussion wasn't about whether dma was good to use or not,

I'm just reacting on one of those urban myths: "DMA is faster".  It's not,
in general.

> of course
> it's preferred, it was just on who's implimentation was better, scsi or
> the ide patch i posted.  Pio mode whores the computer's cpu and is
> wholefully disgusting to use when you have something like dma mode at
> your disposal.

Yes, DMA is more elegant.

> You can stop spreading fud about dma now.

Tsk tsk.

<p>Segher

<p>--- >8 ----
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