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Re: libata - DMA problems ICH7 rev 02

Jan Niklas Hasse wrote:

On Sat, May 3, 2008 at 4:38 AM, Robert Hancock <hancockr@xxxxxxx> wrote:

 This is expected. IOWait just means the system is blocked waiting for IO
and has nothing else to do. It does not mean that DMA is not working.

 [...]

 Looks like you are using DMA:

 ata1.00: configured for UDMA/100
 ata1.01: configured for UDMA/33



Hm.. strange. But the problem is that my system slows down
nevertheless (sometimes the mouse cursor stops moving for a short time
or all my programs don't react). How can i find out what is causing
the problem?

Here I was creating a DVD with dvdauthor which was copying some big
video files. It was nearly impossible to use a web browser, although
CPU load seems only to be 12.7%.

top - 20:33:08 up  4:58,  2 users,  load average: 2.94, 2.81, 2.49
Tasks: 134 total,   2 running, 132 sleeping,   0 stopped,   0 zombie
Cpu(s):  5.0%us,  7.7%sy,  0.0%ni, 16.2%id, 70.1%wa,  0.3%hi,  0.8%si,  0.0%st
Mem:   1019568k total,   996316k used,    23252k free,     1148k buffers
Swap:  2916344k total,    83892k used,  2832452k free,   325284k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 2609 root      15  -5     0    0    0 S    6  0.0   6:41.67 kcryptd
 6344 root      20   0  543m 129m  10m S    3 13.0   6:33.63 Xorg
27062 jhasse    20   0 23164 6424 1176 D    3  0.6   0:11.98 dvdauthor
 6891 jhasse    20   0  208m  18m 8956 S    2  1.9   3:13.41 transmission
27173 jhasse    20   0  263m  24m  12m S    2  2.4   0:00.66 gnome-terminal
  195 root      20   0     0    0    0 S    1  0.0   0:00.14 pdflush

Another example: When I'm burning a disc and at the end, when my drive
finishes the disc (and makes those noises) the computer freezes untill
the CD is finished and ejected (about 3 seconds).

I hope it's the right place to ask here at the mailing list and thanks
for your help so far.
It looks like you have the hard drive and the burner on the same IDE channel? Such problems are unavoidable in this setup since commands to one device on the channel can't execute while the other device is busy (especially for long commands like finalizing the disc). It would be better to move the drives onto separate channels. 
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