rminnich at gmail.com
Sat Jun 20 21:38:11 CEST 2009
On Fri, Jun 19, 2009 at 9:02 AM, Carl-Daniel
Hailfinger<c-d.hailfinger.devel.2006 at gmx.net> wrote:
> However, this locking has to work when some CPUs are in CAR and others
> are in RAM. And that's the big problem.
Let's go back to this original statement. I think it's not correct. We
had decided, on opteron, that bsp does all memory setup -- i.e. sets
up all memory controllers on all sockets. IIRC the opteron code starts
APs up when all of memory is functional. I believe our Intel startup
does this too: BSP sets up memory, and when APs start, memory is
working and usable for stack etc.
If what I am saying is true, that all APs run AFTER the BSP has set up
memory, then there is no issue: all locking can be based in memory,
since NO AP needs to run in CAR mode -- memory is working. IIRC this
is how K8 actually works.
So can we confirm my idea, that no AP need ever run in CAR? If they do
need to run in CAR, why?
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