[linux-audio-user] Ardour - xrun in Atlhon 2.8 !?

Mark Knecht mknecht at controlnet.com
Fri Sep 10 15:47:29 EDT 2004


Alexander Franca wrote:
> 
> Recording:
> ---------------------------------------------------------------------
> /dev/hda:
>  Timing buffer-cache reads:   820 MB in  2.01 seconds = 408.43 MB/sec
>  Timing buffered disk reads:   10 MB in  3.38 seconds =   2.96 MB/sec
> 
> Without Record:
> ---------------------------------------------------------------------
> /dev/hda:
>  Timing buffer-cache reads:   852 MB in  2.01 seconds = 423.94 MB/sec
>  Timing buffered disk reads:    8 MB in  3.00 seconds =   2.66 MB/sec
> 
> Recording again:
> ---------------------------------------------------------------------
> /dev/hda:
>  Timing buffer-cache reads:   812 MB in  2.00 seconds = 405.25 MB/sec
>  Timing buffered disk reads:   10 MB in  3.66 seconds =   2.74 MB/sec
> 
> Runing Jack
> ---------------------------------------------------------------------
> /dev/hda:
>  Timing buffer-cache reads:   1028 MB in  2.00 seconds = 512.80 MB/sec
>  Timing buffered disk reads:   10 MB in  3.26 seconds =   3.07 MB/sec
> 
> 
> Thats it?
> 
> []'s
> Alexander

And this looks like your problem. Your disk throughput is so low that 
you're probably not getting the bandwidth that you need. Probably DMA is 
not turned on.

man hdparm will tell you more, but a very basic test setting you could 
try could be something like:

hdparm -A 1 -m 16 -a 64 -c 1 -d 1 -u 1 /dev/hda

(read man hdparm to understand the meaning of each of these.)

Try setting -a up and down and look at the change in throughput. If 
setting it lower doesn't hurt then push it down. If raising it helps 
push it up. I don't know what type of drive you have but you should be 
able to get anywhere from 15MB/S up to 50MB/S depending on your PC, 
drive controller and the drive.



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