Native preemption is the culprit [was Re: today's CURRENT lockups]

[Robert Watson]

On Mon, 12 Jul 2004, Arjan van Leeuwen wrote:

> > I tried to upgrade my kernel from 5.2.1 to -CURRENT and cvsupped
> > post-preemption. Running a UP-Kernel on a UP-Machine with either
> > SCHED_ULE or SCHED_BSD froze the machine under heavy load. It doesn't
> > survive a buildworld or a medium port-build.
> 
> Same here. 

Per my earlier post, I've experienced similar unreliability.  The work
around I'm using is to build with "#define PREEMPTION" from param.h
disabled.  This results in a quite usable kernel, although quite probably
more poor interrupt handling latency, etc.

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