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Date:      Tue, 4 Jul 2006 09:20:10 -0400 (EDT)
From:      Daniel Eischen <deischen@freebsd.org>
To:        Peter Wemm <peter@wemm.org>
Cc:        threads@freebsd.org, Robert Watson <rwatson@freebsd.org>, davidxu@freebsd.org
Subject:   Re: Strawman proposal: making libthr default thread implementation?
Message-ID:  <Pine.GSO.4.64.0607040914430.11608@sea.ntplx.net>
In-Reply-To: <200607032253.35982.peter@wemm.org>
References:  <200607032253.35982.peter@wemm.org>

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On Mon, 3 Jul 2006, Peter Wemm wrote:

> On Mon, 3 Jul 2006, Daniel Eischen wrote:
>> On Mon, 3 Jul 2006, David Xu wrote:
>>
>>> On Monday 03 July 2006 19:48, Daniel Eischen wrote:
>>>
>>>> Yes, you have to support PTHREAD_PRIO_PROTECT, PTHREAD_PRIO_INHERIT
>>>> mutexes, and SCHED_RR, SCHED_FIFO, and SCHED_SPORADIC scheduling
>>>> (hopefully not under the restriction that you are a privileged
>>>>  user).
>>>>
>>>
>>> I would tell you don't implement system scope thread in libpthread,
>>> because system scope thread does not work in the way you said here,
>>> it seems you are telling user that the libpthread is fully working in
>>> the way, but the reality is not, without a correct kernel support,
>>> I don't think you should introduce system scope thread into
>>> libpthread, please remove this feautre if you think libpthread should
>>> work in the way.
>>
>> I don't believe that system scope threads have to abide
>> by SCHED_RR, SCHED_FIFO, and SCHED_SPORADIC scheduling
>> since their contention scope is different.
>
> It sounds like (by your definition) that switching to a libthr that only
> has system scope threads means we don't have to implement those modes,
> right?

Actually, I confused contention scope with allocation domain.
Threads with scope system contention scope have to compete
with all other system scope threads regardless of the process'
priority.  On a single CPU system (allocation domain = 1),
system scope threads with SCHED_RR, SCHED_FIFO, and (if supported) 
SCHED_SPORADIC scheduling attributes need to be scheduled
accordingly.

-- 
DE



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