rawhide slow like a snail because of kernel debugging?

[Michael Schwendt]

On Tue, 12 Feb 2008 14:41:53 +0000, Christopher Brown wrote:

> > It has begun some weeks ago in rawhide and is the same in F9 Alpha,
> > which I installed from jigdo CD images.
> >
> > The entire system is slow whatever it does. Loadavg jumps up
> > quickly. When running a simple yum update, loadavg goes above 6. User
> > processes don't seem to get as much cpu power as would be possible.
> > Windows take seconds to open. The GNOME Desktop is not as responsive
> > as in F8 either. Opening dialogs, clicking buttons, there seems to be
> > a penalty on everything. It's unbearable. Testing rawhide or F9 is no
> > fun at all. Why is this? I remember that during Fedora Core test
> > releases various kernel debugging features are enabled. Is this the
> > reason also this time? Has it become much more cpu power hungry than
> > e.g. with FC7 and older?
> 
> >From the wiki:
> 
> In Rawhide/devel kernels (and in -debug flavors of released kernels),
> Fedora uses the SLUB allocator with full slab debugging enabled by
> default. The debugging might cause problems in some rare cases: memory
> allocations can fail, causing the system to panic. Slab debugging can
> be disabled with the option slub_debug=-  (a single minus sign.) Note,
> that this option will hide an actual bug that really should be
> reported and fixed rather than worked around.

Doesn't answer the original question, however.

Btw, the thread is longer and contains posts with evidence that X is
the culprit.