SCHED_ULE should not be the default

[Lars Engels]

On Thu, Dec 15, 2011 at 02:20:04PM -0000, Steven Hartland wrote:
> With all the discussion I thought I'd give a buildworld
> benchmark a go here on a spare 24 core machine. ULE
> tested fine but with 4BSD it wont even boot panicing
> with the following:-
> http://screensnapr.com/v/hwysGV.png
> 
> This is on a clean 8.2-RELEASE-p4
> 
> Upgrading to RELENG_9 fixed this but its a bit concerning
> that just changing the scheduler would cause the machine
> to panic on boot.
> 
> Its only a single run so varience could be high but here's
> the result of a buildworld on this machine running the
> two different schedulers:-
> 4BSD: 24m54.10s real 2h43m12.42s user 56m20.07s sys
> ULE:  23m54.68s real 2h34m59.04s user 50m59.91s sys
> 
> What really sticks out is that this is over double that
> of an 8.2 buildworld on the same machine with the same
> kernel
> ULE:  11m12.76s real 1h27m59.39s user 28m59.57s sys

9.0 ships with gcc and clang which both need to be compiled, 8.2 only
has gcc.

> 
> This was run 9.0-PRERELEASE kernel due to 4BSD panicing
> on boot under 8.2.
> 
> So for this use ULE vs 4BSD is neither here-nor-there
> but 9.0 buildworld is very slow (x2 slower) compared
> with 8.2 so whats a bigger question in my mind.
> 
>     Regards
>     Steve

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