On 12/22/2009 06:12 PM, Anthony Liguori wrote:
I think the only two Fully Correct approachs are to support a very
specific CPU (e.g. Xeon-X5270) or provide the ability to individually
tweak cpu flags.
Yes. By a curious coincidence these are what the hardware vendors
define (unlike compat classes etc.).
The notion of compatibility classes should probably be left to
management tools. We can make it a lot easier for them though by
supporting turning point CPU models.
Agreed.
For instance, Xeon-X5570 should be a least common denominator for
Nehalem processors. It's probably better for users too. It's easier
for them to answer "do I have anything older than a Xeon-X5570" than
to ask "do I have any Woodcrest class processors".
I encounter this confusion a lot. I usually ask people whether they
have a Nehalem processor when debugging something and their response
is always, I have a Xeon-XYZ, is that Nehalem?
This is complicated by the fact that processors don't have straight-line
development, and that marketing names don't correspond to anything. For
example Xeon can be any of the Pentium 4, Core, Core 2, and Nehalem (and
perhaps other) microachitectures. A newer Xeon is often introduced with
an older core (usually for larger machines) than previously existing Xeons.
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error compiling committee.c: too many arguments to function
