Re: [2.6.10-rc1 and prev] System unuseable while writing to disk

[Bill Davidsen <davidsen@tmr.com>]

Prakash K. Cheemplavam wrote:
> Hi,
> 
> I have a problem which doesn't seem to be connected to the i/o 
> schedulers, because all I tested (cfq, deadline, noop) show the same:
> 
> While writing (when the kernel actually commits to hd) my system gets 
> very unresponsive esp when another app I want to use wants to write 
> (read?) from hd, as well. This is *not* a UDMA problem (at least no 
> apparent...)! More specific:
> 
> I wrote this primitive code for writing sequentially:

May I suggest running "vmstat 1" while this is happening? Looking at the 
waitio time vs. transfer rates might reveal something. If it all looks 
the same post a small section, if it starts off looking like one thing 
and then changes as buffers fill, data from start to steady state might 
assist someone in helping.

I can't say that I see any such thing with ext[23], so it may be a 
reiser issue and someone else will have to help. Did you look at the 
logs to see that there are no useful warnings there?

-- 
    -bill davidsen (davidsen@tmr.com)
"The secret to procrastination is to put things off until the
  last possible moment - but no longer"  -me