Re: cfq misbehaving on 2.6.11-1.14_FC3

[Andrew Morton <akpm@osdl.org>]

<spaminos-ker@yahoo.com> wrote:
>
> Hello, I am running into a very bad problem on one of my production servers.
> 
>  * the config
>  Linux Fedora core 3 latest everything, kernel 2.6.11-1.14_FC3
>  AMD Opteron 2 GHz, 1 G RAM, 80 GB Hard drive (IDE, Western Digital)
> 
>  I have a log processor running in the background, it's using sqlite for storing
>  the information it finds in the logs. It takes a few hours to complete a run.
>  It's clearly I/O bound (SleepAVG = 98%, according to /proc/pid/status).
>  I have to use the cfq scheduler because it's the only scheduler that is fair
>  between processes (or should be, keep reading).
> 
>  * the problem
>  Now, after an hour or so of processing, the machine becomes very unresponsive
>  when trying to do new disk operations. I say new because existing processes
>  that stream data to disk don't seem to suffer so much.

It might be useful to test 2.6.12-rc6-mm1 - it has a substantially
rewritten CFQ implementation.