FC5T2 and Development issues, observations, and questions

Dave Jones davej at redhat.com
Tue Jan 17 17:09:48 UTC 2006

On Tue, Jan 17, 2006 at 08:59:57AM -0800, Nathan Grennan wrote:

 > 2. What is up with x86_64 kernels always being SMP enabled? I noticed a 
 > comment in the release notes, but no reason given as to why. I would 
 > think this could be problematic for debugging unless there is some boot 
 > option that makes the kernel act 100% like it would with a UP kernel.

It's been covered on the lists a few times.  In short, the number of
dual-core/hyperthreaded/smp x86-64s in the wild far outweigh the
uniprocessor variants (soon, even laptops will be moving to dual-core/HT),
and the overhead of running spinlocks on UP is negligable
(and there's work ongoing to make it disappear completely).

Less kernel images overall is a good thing for a number of reasons.
less cd space, less mirror bandwidth, faster build times, being some of
the 'off the top of my head' answers, but there's also value in having
every system going through the same codepath from a debugging standpoint.

If it wasn't for the zillion crappy legacy i386 systems, I'd love to
do the same for 32 bit kernels too, but x86-32 has so many systems that
won't boot an smp kernel it's unfunny.

 > 9. Currently after recent development updates multiple panel applets 
 > crash on login, and one crashes on log out.

gnome-session had a debug switch set, it's been disabled in latest builds,
but didn't make this mornings rawhide push.


More information about the test mailing list