cvs commit: src/sys/kern sched_ule.c

Robert Watson rwatson at
Wed Jul 7 09:06:19 PDT 2004

On Wed, 7 Jul 2004, John Baldwin wrote:

> On Tuesday 06 July 2004 01:57 am, Robert Watson wrote:
> > rwatson     2004-07-06 05:57:30 UTC
> >
> >   FreeBSD src repository
> >
> >   Modified files:
> >     sys/kern             sched_ule.c
> >   Log:
> >   Temporarily disable preemption in SCHED_ULE due to reported panics and
> >   hangs due to recent preemption changes.  This change appears to remove
> >   the panic that I was running into, but at the cost of increasing
> >   ithread scheduling latency, and as such is a temporary band-aid until
> >   jhb has a chance to resolve the ule<->preemption interaction that is
> >   the source of the problem.  If it doesn't fix the problem for others--
> >   sorry!
> It it just broken on SMP?  I actually did the commit from a UP
> preemption kernel using SCHED_ULE from within X11 with KDE, etc.
> running. 

I was only able to reproduce this with an SMP-enabled kernel; however, the
reports on -current were unclear and I didn't follow up on each one. 

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert at      Principal Research Scientist, McAfee Research

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