Re: ULE/yielding patch for testing.

On Wed, October 3, 2007 17:07, Nick Evans wrote:
> On Tue, 2 Oct 2007 16:53:33 -0700 (PDT)
> Jeff Roberson <jroberson_at_chesapeake.net> wrote:
>
>> Enclosed is a patch that does two things:
>>
>> 1)  Reduces UP context switch time by over 10% making it faster than
>> 4BSD
>> on UP.  On SMP it's hard to compare since ULE can do as many as 30x as
>> many switches per second on my 8way system.
>>
>> 2)  Restores old sched_yield() behavior from 6.x.  This was changed in
>> -current unintentionally I think.
>>
>> I'd appreciate any extra testing.  The ULE context switch time
>> improvements required some changes to the frequency that we recalculate
>> priorities.  I'm mostly interested in hearing whether this causes any
>> regression in normal workloads.
>>
>> Those of you still using 4BSD can also verify that the yield changes
>> don't
>> cause any problems there.
>>
>> Thanks,
>> Jeff
>
> Jeff,
>
> I haven't noticed any adverse affects with this patch on yesterdays
> CURRENT+ULE. System is a Pentium D 915 with 1 gig ram. Built a bunch of
> larger
> ports while browsing in firefox and setting up enlightenment-devel,
> interactivity was good. Enlightenment's eye-candy stayed very fluid.
>
> Nick
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Hi,

Running -current as of tuesdaynight CET.

FreeBSD hulk.superhero.nl 7.0-CURRENT FreeBSD 7.0-CURRENT #4: Wed Oct  3
08:19:30 UTC 2007     root_at_hulk.superhero.nl:/usr/obj/usr/src/sys/GENERIC 
amd64

I've done the following (had to as I did not have the actual diff available):

copy text from
http://lists.freebsd.org/pipermail/freebsd-current/attachments/20071002/30d18099/yield-0001.bin
into a file saved in /tmp

#cd /usr/src
#patch < /tmp/patchile

I had to tell the patch with which files I wanted the patchfiles to
compare with. Found this weird but they did apply correctly.

I've recompiled my Kernel with SCHED_ULE and rebooted.

After boot I got up to the login window after which it instantly paniced
with: panic: Invalid priority 128 on timeshare runq

Maybe this error was caused by the method of patching used by me? Can you
please provide me the patch again by email, if this could solve the issue.

If more information is required I am more than happy to provide.

Rgds,

Patrick