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

[Jon Noack]

On 07/09/04 12:25, Steve Kargl wrote:
> On Fri, Jul 09, 2004 at 12:19:09PM -0500, Jon Noack wrote:
>> On 07/09/04 12:15, John Baldwin wrote:
>>> My test machine is not a true SMP machine either, just HTT.  It
>>> has been running a -j 256 worldloop overnight with no problems,
>>> so I committed a slightly modified version of the patch
>>> yesterday.
>> 
>> Did you test with a UP kernel?  After your latest commit I have
>> been experiencing regular hard locks on my pre-HTT P4 machine.
>> Backing out rev. 1.114 of sched_ule.c fixes it.  See my previous
>> message (Re: FreeBSD keeps hanging......): 
>> http://docs.freebsd.org/cgi/mid.cgi?40EECC49.3070501
> 
> I've tested it on a UP kernel (HTT enabled, ACPI disabled, APIC
> enabled, ULE).   Appears to work fine.

Perhaps it's just extraneous information, but if it's really a UP kernel 
(as in, no 'options SMP') then whether you have HTT enabled doesn't 
matter at all -- the kernel won't use it.

Jon