ULE scheduler not quite there yet

Scott Long scottl at samsco.org
Sat Sep 18 15:50:29 PDT 2004

Kris Kennaway wrote:
> On Sat, Sep 18, 2004 at 12:06:43PM -0700, Sean McNeil wrote:
>>I've had good luck with the 4BSD scheduler and PREEMPTION on so I
>>thought I would try the ULE scheduler.  Was up for just a short time
>>before I got the following on my amd64 machine:
> This is a known problem, BTW.
> Kris

There is likely a message at the top of the dmesg output that says,

"WARNING: Kernel PREEMPTION is unstable under SCHED_ULE."

This has been discussed quite a bit recently and we decided that
focusing on the 4BSD scheduler gave us a better chance at having a
stable system for 5.3.  I still welcome anyone to step in and
investigate the problems with ULE.


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