Re: libata - DMA problems ICH7 rev 02

[Robert Hancock <hancockr@shaw.ca>]

Jan Niklas Hasse wrote:
> On Sat, May 3, 2008 at 4:38 AM, Robert Hancock <hancockr@shaw.ca> 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.