Bumping MAXCPU for MIPS configurations

[Jayachandran C.]

On Tue, Jul 19, 2011 at 6:37 AM, Attilio Rao <attilio at freebsd.org> wrote:
> 2011/7/3 Jayachandran C. <c.jayachandran at gmail.com>:
>> On Wed, Jun 29, 2011 at 4:48 PM, Attilio Rao <attilio at freebsd.org> wrote:
>>> 2011/6/29 Jayachandran C. <c.jayachandran at gmail.com>:
>>>> On Wed, Jun 29, 2011 at 3:10 PM, Attilio Rao <attilio at freebsd.org> wrote:
>>>>> [ Please CC me in replies as I'm not subscribed to this mailing list ]
>>>>>
>>>>> I'm planning to bump MAXCPU for all the kernel configurations
>>>>> requiring it, as long as the latest cut of largeSMP changes is
>>>>> completed.
>>>>>
>>>>> Anyway, I'm not really sure what MIPS configurations may benefit from
>>>>> a larger number of MAXCPU. Probabilly XLP should, for what I've heard,
>>>>> but I'd like to get a precise mapping between configurations that want
>>>>> to bump the number and the actual maximum number of CPUs to be
>>>>> supported.
>>>>
>>>> An XLP SoC has 32 cpus (8cores x 4 hw threads per core), and 4 of
>>>> these can be interconnected to have upto 128 cpus.  We have an XLP
>>>> port running on one chip with 32cpus, but there is interest in trying
>>>> out 2 chip (64cpus) and 4 chip(128 cpus) configurations, so this is
>>>> something I want to do when I get access to multi-chip boards for
>>>> FreeBSD development.
>>>
>>> I'll bump MAXCPU to 128 for XLP then, thanks.
>>> Do you have informations about XLR?
>>
>> For XLR the the MAXCPU should be 32 (8 cores x 4 threads per core on
>> the SoC). We cannot connect multiple chips together like the XLP.
>
> So what do you think about this patch?:
> http://www.freebsd.org/~attilio/maxcpu_bump.diff
>
> I already got Marcel's approval on ia64 part, but I need you review
> the mips bits.

For the XLP changes, we don't really need 128 for MAXCPU now.  The ICI
interface driver which is needed to connect multiple XLPs together to
get 64/128 cpus have not been checked in yet.  I plan to do this a few
months down the line.

Regards,
JC.