Re: ULE/yielding patch for testing.

On Wed, 3 Oct 2007, Gelsema, P (Patrick) - FreeBSD wrote:

> 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

I believe I have fixed this bug in the enclosed patch.  It is rooted from 
/usr/src/sys so you should cd there to apply it.

Thanks,
Jeff

>
> 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
>
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