SCHED_ULE should not be the default

Steven Hartland killing at multiplay.co.uk
Thu Dec 15 14:19:48 UTC 2011


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

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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