Re: advice sought: practicality of SMP cache coherency implementedin assembler (and a hardware detect line)

From: Alan Cox
Date: Mon Mar 28 2011 - 18:17:53 EST


> ok - well, having thought about this a little bit (in a non-detailed
> high-level way) i was sort-of hoping, as alan hinted at, to still do
> SMP, even if it's slow, for userspace. the primary thing to prevent
> from happening is to have kernelspace data structures from
> conflicting.
>
> i found kerrigan, btw, spoke to the people on it: louis agreed that
> the whole idea was mad as hell and was therefore actually very
> interesting to attempt :)
>
> as a first approximation i'm absolutely happy for existing pthreads
> applications to be forced to run on the same core.

The underlying problem across a cluster of nodes can be handled
transparently. MOSIX solved that problem a very long time ago using DSM
(distributed shared memory). It's not pretty, it requires a lot of tuning
to make it fly but they did it over comparatively slow interconnects.

Alan
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