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Re: mutexes, locks and so on...

On Fri, Nov 12, 2010 at 03:25:04PM +0100, Johnny Billquist wrote:
> So what you are arguing is that MI needn't be so much MI anymore,
> and that supporting anything more than mainstream today is more to
> be considered a lucky accident than a desired goal?

It is not about mainstream. Please tell me one architecture that has
been created in the last 10 years, supports at least 32bit address
space, virtual memory and doesn't support either CAS or LL/SC. I would
be very surprised if there is one. Like I said, there has been a lot of
research into scalable primitives and algorithms and processor design
has changed accordingly. The ras-like UP implementation of CAS is almost
free as long as your interrupt rate is much lower than the rate of CAS
operations. There are a lot of low hanging fruits for VAX like providing
proper assembler versions of the atomic add etc, which sound feasible
from the docs I found. There are other areas where VAX hasn't kept up
with the "mainstream" architectures. pmap_growkernel to name one with
practical implications.


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