Re: Interactivity issue in 2.6.25-rc3

From: Ingo Molnar
Date: Fri Feb 29 2008 - 10:58:16 EST



* Ray Lee <ray-lk@xxxxxxxxxxxxx> wrote:

> But it's good to keep in mind that the scheduler can't do anything
> about slowdowns due to tasks being swapped out or waiting on reads
> from the disk. I mention this as shortly after CFS got into mainline,
> something changed in the VM that seems to make my system spend a lot
> more time in IO wait, causing the system to be much less responsive
> than it used to be.
>
> Unfortunately it seems to be dependent upon the history of what tasks
> I've run and their memory usage, so it's been hard to come up with a
> reproducible test case (well that and a complete lack of time). All I
> can say is that I've seen what you've reported as well, though it had
> nothing to do with using any 3d applications, just a browser, editor,
> gcc, etc.

what does latencytop say about those delays, what causes them? It should
be able to capture all sorts of latency sources in the system.

Ingo
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