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

From: Bill Davidsen
Date: Wed Nov 10 2004 - 15:31:41 EST


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@xxxxxxx)
"The secret to procrastination is to put things off until the
last possible moment - but no longer" -me

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