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Date: Mon, 18 Jul 2005 20:31:32 -0700
To: Daniel Walker <dwalker@mvista.com>
Cc: Ingo Molnar <mingo@elte.hu>, Dave Chinner <dgc@sgi.com>,
       Nathan Scott <nathans@sgi.com>, Steve Lord <lord@xfs.org>,
       linux-kernel@vger.kernel.org, linux-xfs@oss.sgi.com,
       Christoph Hellwig <hch@infradead.org>
Subject: Re: RT and XFS
Message-ID: <20050719033132.GB22060@nietzsche.lynx.com>
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From: Bill Huey (hui) <bhuey@lnxw.com>
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On Fri, Jul 15, 2005 at 09:16:55AM -0700, Daniel Walker wrote:
> I don't agree with that. But of course I'm always speaking from a real
> time perspective . PI is expensive , but it won't always be. However, no
> one is forcing PI on anyone, even if I think it's good ..

It depends on what kind of PI under specific circumstances. In the general
kernel, it's really to be avoided at all costs since it's masking a general
contention problem at those places. In a formally provable worst case system
using priority ceiling emulation and stuff, PI really valuable. How a system
like the Linux kernel fits into that is a totally different story. General
purpose kernels using general purpose facilities don't.

That's how I see it.

bill