Re: 2.6.36 io bring the system to its knees

From: Jesper Juhl
Date: Thu Nov 04 2010 - 19:59:45 EST


On Thu, 28 Oct 2010, Chris Mason wrote:

> On Thu, Oct 28, 2010 at 03:30:36PM +0200, Ingo Molnar wrote:
> >
> > "Many seconds freezes" and slowdowns wont be fixed via the VFS scalability patches
> > i'm afraid.
> >
> > This has the appearance of some really bad IO or VM latency problem. Unfixed and
> > present in stable kernel versions going from years ago all the way to v2.6.36.
>
> Hmmm, the workload you're describing here has two special parts. First
> it dramatically overloads the disk, and then it has guis doing things
> waiting for the disk.
>

Just want to chime in with a 'me too'.

I see something similar on Arch Linux when doing 'pacman -Syyuv' and there
are many (as in more than 5-10) updates to apply. While the update is
running (even if that's all the system is doing) system responsiveness is
terrible - just starting 'chromium' which is usually instant (at least
less than 2 sec at worst) can take upwards of 10 seconds and the mouse
cursor in X starts to jump a bit as well and switching virtual desktops
noticably lags when redrawing the new desktop if there's a full screen app
like gimp or OpenOffice open there. This is on a Lenovo Thinkpad R61i
which has a 'Intel(R) Core(TM)2 Duo CPU T7250 @ 2.00GHz' CPU, 2GB of
memory and 499996 kilobytes of swap.


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Jesper Juhl <jj@xxxxxxxxxxxxx> http://www.chaosbits.net/
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