Re: page color initialization

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Fri, Sep 30, 2011 at 03:36:14PM +0900, Masao Uebayashi wrote:
> 
> - is there any architecture which allows MP with different cache-line sizes?

At a guess, this can probably happen on an SGI Challenge (a real Challenge,
that is, a DM, L, or XL, not a "Challenge S").  It is possible it can also
happen on supported configurations of the successor CrayLink-based
platforms (Origin 200/2xxx/3x0/3xxx) even including Altix though I doubt
such configurations were ever supported even by SGI.

Do we care?  Probably not.  But Challenge and Origin are nice examples
of how weird big MP platforms can be and still get good performance
through excellent kernel implementation (Origin is very, very NUMA and
the Irix kernel deals with this very very well) so sometimes it might
be worth thinking about what we'd need to do to run on such platforms with
acceptable performance.

It's unfortunate that even after excising most of the AT&T code -- maybe
all? -- SGI never really opened up any of the Irix sources except XFS.

Thor