Bumping MAXCPU for MIPS configurations

[Jayachandran C.]

On Tue, Jul 19, 2011 at 5:18 PM, Attilio Rao <attilio at freebsd.org> wrote:
> 2011/7/19 Jayachandran C. <c.jayachandran at gmail.com>:
>> 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.
>
> As I'm going to bump the MAXCPUs for all the architectures now, where
> needed, I'm not sure why we should not do that now, even if the full
> support is not ready yet.
>
> If you are strongly against the change I won't commit it, otherwise it
> would be good to bump now, along with amd64 and ia64.

I have no issues with bumping it up to 128. Thought I would just note
that we don't support it yet, and hopefully we can remedy that soon :)

JC.