x86_64 smp 2.6.15-1.1781_FC4 in ?

[Dave Jones]

On Tue, Jan 03, 2006 at 02:15:35PM +0100, dragoran wrote:

 > >Do you mean why not have a non-smp kernel for x86_64? If so probably 
 > >because many(most?/all?) EMT64 CPUs support HT or dual core.
 > >
 > there are many non dualcore am64 chips arround

lock prefix on uniprocessor AMD systems is a lot lower overhead
than it is on Intel. The performance impact of running with spinlocks
on UP there is tiny. The gain is that we save shipping an extra
kernel on the CD, the installer gets simpler, and we have a single
codepath on that architecture.

There is work ongoing upstream that may make it in for 2.6.16 to
actually nop out the spinlocks on UP configurations, making them
completely free.

 > http://people.redhat.com/davej/kernels/Fedora/FC4/RPMS.kernel/kernel-2.6.15-1.1781_FC4.x86_64.rpm
 > and 
 > http://people.redhat.com/davej/kernels/Fedora/FC4/RPMS.kernel/kernel-smp-2.6.15-1.1781_FC4.x86_64.rpm
 > smp is already enabled in the non smp kernel.. so why do we have 2 
 > kernels with different names but same config? (or is there a difference 
 > beween them)

The unification happened after FC4 was released. FC5 will be the
first single-kernel x86-64 release.

		Dave