Re: what's next for the linux kernel?

[Andi Kleen]

Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> writes:

> On Llu, 2005-10-03 at 22:07 +0100, Luke Kenneth Casson Leighton wrote:
> >  made?  _cool_.  actual hardware.  new knowledge for me.  do you know
> >  of any online references, papers or stuff?  [btw just to clarify:
> >  you're saying you have a NUMA bus or you're saying you have an
> >  augmented SMP+NUMA+separate-parallel-message-passing-bus er .. thing]
> 
> Its a standard current Intel feature. See "mwait" in the processor
> manual. The CPUs are also smart enough to do cache to cache transfers.
> No special hardware no magic.

It's unfortunately useless for anything but kernels right now because
Intel has disabled it in ring 3 (and AMD doesn't support it yet)
And the only good use the kernel found for it so far is fast wakeup
from the idle loop.

> And unless I want my messages to cause interrupts and wake events (in
> which case the APIC does it nicely) then any locked operation on memory
> will do the job just fine. I don't need funky hardware on a system. The
> first point I need funky hardware is between boards and that isn't
> consumer any more.

Firewire + CLFLUSH should do the job.

-Andi
 
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