cvs commit: src/sys/amd64/conf GENERIC

Scott Long scottl at
Wed Dec 13 20:32:04 PST 2006

mjacob at wrote:
>> David E. O'Brien wrote:
>>> obrien      2006-12-14 03:57:34 UTC
>>>   FreeBSD src repository
>>>   Modified files:        (Branch: RELENG_6)
>>>     sys/amd64/conf       GENERIC   Log:
>>>   Turn on SMP in the default kernel.
>>>   Most FreeBSD/amd64 machines are either multi-socket and/or multi-core.
>>>     Revision    Changes    Path
>>>   1.439.2.16  +3 -0      src/sys/amd64/conf/GENERIC
>> I guess you missed /sys/amd64/conf/SMP and all of the work that was done
>> in sysinstall to detect and auto-install an SMP kernel.  Idiot.  Welcome
>> back.
> First of all, no need to be so surly- I'm sure David meant well.
> Secondly, I would *like* to have SMP on as a default in RELENG_6 for 
> amd64, as it would avoid doing what I've done twice already- fresh 
> sysinstall may or may not have installed an SMP kernel but going off and 
> building GENERIC then lost me my SMP. It's sort a violation of POLA.

What is in RELENG_6 is a transition step from UP-by-default that has
existed since the beginning of time, to SMP-by-default that is enabled
in 7-CURRENT.  The POLA aspect of compiling GENERIC was discussed, and
we decided that there was enough documentation on it in place to help
people understand what was going on, and that the transition steps were
worth the risk.

There wasn't a full switchover to SMP at 6.0 because an SMP kernel on a
UP system incurs a measurable runtime overhead, and we wanted to present
a system that showed the best of FreeBSD to people who wanted to run it
out-of-the-box.  This includes both novice users as well as OS review
websites.  We also knew that anyone tweaking their kernel config falls
out of the novice category.  So a lot of work was done to add
infrastructure for distributing multiple kernels, give sysinstall the
tools to make automatic decisions, and add documentation to help users
through the transition.  In all, I think that it has turned out well,
and there have been very few complaints of POLA to the mailing lists.


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