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Date: Tue, 23 Sep 2008 14:44:36 -0400
From: Mikhail Teterin <mi+mill@aldan.algebra.com>
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To: "Paul B. Mahol" <onemda@gmail.com>
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Cc: stable@freebsd.org
Subject: Re: 7.0-stable: a hung process - scheduler bug?
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Paul B. Mahol ΞΑΠΙΣΑΧ(ΜΑ):
>> Let me know, what else I can do to help fix this bug -- I'm going to
>> reboot the machine tonight... Should I switch to SCHED_ULE as a
>> work-around?
>>     
>
> SCHED_BSD4 is suboptimal for 4 CPUs, and it is replaced with SCHED_ULE
> on 7 STABLE.
>   
Thanks, Paul for the explanation. I've heard of some problems still 
lingering in the ULE and figured, I'll stay with the BSD-scheduler for a 
while. I guess, it is time to switch.
However, what I'm seeing on my system today is evidence of the scheduler 
having a bug, rather than merely being suboptimal. If the old scheduler 
is still maintained and supposed to work (however sub-optimally) in 
4-CPU configurations, I'd expect either inquiries for more 
debug-information or assurances, that the bug is known and worked on.
In the July 26th sys/conf/NOTES file the SCHED_BSD4 is still on the 
default option....
Yours,

    -mi