F16 slowness

[Adam Williamson]

On Sat, 2011-09-10 at 12:06 -0500, Mike Chambers wrote:
> On Sat, 2011-09-10 at 12:42 +0200, Michael Schwendt wrote:
> > On Fri, 9 Sep 2011 15:46:21 -0400, DJ (Dave) wrote:
> > 
> > > you can turn off some of the heavier weight debugging by booting
> > > the 3.0 kernels with "slub_debug=-"
> > > (In the 2.6.40 builds, this is only on in the -debug flavor)
> > > 
> > > Debugging options are going to be turned off for the next builds
> > > in time for the beta.
> > 
> > Based on first impressions, this option makes a difference. At least
> > for the "xterm -e mc" resize test, under the assumption that I've not
> > made a typo when adding this in GRUB2 command-line.
> > 
> > Together with the workaround from clutter bug 720605, Claws Mail also
> > no longer suffers from missing subject lines in its Folder Summary View.
> > 
> > Additionally, I've yet to see the "vertical scrollbar repeat effect"
> > where a single mouse-click moves up/down more than 1 page as if the
> > button is stuck.
> 
> So, is the kernel you tested with debugging off, one built from Fedora
> or a custom one?  Which version,
> kernel-3.1.0-0.rc5.git0.0.fc16.x86_64.rpm?

I think Michael was testing the "slub_debug=-" parameter.

In the bug report, I noted that I recompiled rc5 with debugging disabled
and it does indeed clear up all the performance problems. Seems like the
debugging overhead got a lot heavier between 3.0 and 3.1, so you really
see the sluggishness in 3.1 kernels. See
https://bugzilla.redhat.com/show_bug.cgi?id=735268 for the numbers.
-- 
Adam Williamson
Fedora QA Community Monkey
IRC: adamw | Twitter: AdamW_Fedora | identi.ca: adamwfedora
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