Date: Fri, 27 May 2005 22:53:18 -0700
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Lee Revell <rlrevell@joe-job.com>, "Bill Huey (hui)" <bhuey@lnxw.com>,
       Andi Kleen <ak@muc.de>, Sven-Thorsten Dietrich <sdietrich@mvista.com>,
       Ingo Molnar <mingo@elte.hu>, dwalker@mvista.com, hch@infradead.org,
       akpm@osdl.org, linux-kernel@vger.kernel.org
Subject: Re: RT patch acceptance
Message-ID: <20050528055318.GB2958@nietzsche.lynx.com>
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On Sat, May 28, 2005 at 02:43:30PM +1000, Nick Piggin wrote:
> If you are talking about soft-RT, or things running on Linux today,
> then sure they'll keep working. Even some or all of PREEMPT_RT may
> be merged into the Linux guest too, for better soft-RT. I haven't
> been arguing against that.

Hard RT guarantee are very possible, not in years, but months (possibly
already) under constraints previously outlined.

[dual complexity issues snippeted]

> I agree we'll never have a fully functional hard-RT Linux kernel.
> But this thread hasn't been about whether or not the RT task knows
> what it is doing (we assume it does), but the possibility of making
> more parts of the kernel able to provide some RT guarantee (ie. so
> said RT task *can* use more functionality).

No sane RT app person is going to call into the kernel and expect
guarantees in a general purpose system. Folks doing this kind of
RT work will have at least a path that they can follow to *possibly*
make this happen. It's all conjecture at the moment and it won't be
known until somebody takes a shot at it and all associated kernel
issues. It's most definitely a worthy project.

If this happens Linux would be an ideal kernel for digital video
recorders and such.

bill

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