HEADS UP! Debugging, SMP changed in RELENG_6

Scott Long
Sat, 17 Sep 2005 21:00:21 -0000

All,

I've turned off kernel deubgging (INVARIANTS, WITNESS, KDB) and malloc
debugging (the default is now 'aj) in the RELENG_6 branch in preparation
for 6.0-BETA5.  I've also turned off SMP in the i386 and amd64 GENERIC
kernels and have added and SMP kernel config for those architectures.
All of these changes are nearly identical to what is in RELENG_5.  All
of this was done to facilitate performance measurement of the upcoming
release and to recognize that our buglist is shrinking considerably and
thus the release will be coming soon.

### IMPORTANT ###

If you are using a stock GENERIC kernel on amd64 or i386 and expect
multiple CPUs to be enabled, you must either switch to the SMP kernel
config, or add the 'options SMP' line back to the GENERIC config.
Multiple CPUs, including mutli-core and Hyperthreading, will only be
enabled when this option is included.  Hyperthreading also requires
that you add the line 'machdep.hyperthreading_allowed=1' to
/boot/loader.conf.

Given the growth of multicore offerings from AMD and Intel, the default
on SMP may change in future releases as SMP systems become ubiquitous.
Appropriate warning will be given on the mailing lists if this happens.

Scott