Bumping MAXCPU on amd64?

[John Baldwin]

On Wednesday, September 22, 2010 6:36:56 am Maxim Sobolev wrote:
> Hi,
> 
> Is there any reason to keep MAXCPU at 16 in the default kernel config? 
> There are quite few servers on the market today that have 24 or even 32 
> physical cores. With hyper-threading this can even go as high as 48 or 
> 64 virtual cpus. People who buy such hardware might get very 
> disappointed finding out that the FreeBSD is not going to use such 
> hardware to its full potential.
> 
> Does anybody object if I'd bump MAXCPU to 32, which is still low but 
> might me more reasonable default these days, or at least make it an 
> kernel configuration option documented in the NOTES?

?

% grep MAXCPU ~/work/freebsd/svn/head/sys/amd64/include/param.h 
#define MAXCPU          32
#define MAXCPU          1

In fact:

% grep MAXCPU ~/work/freebsd/svn/stable/8/sys/amd64/include/param.h 
#define MAXCPU          32
#define MAXCPU          1

Unfortunately this can't be MFC'd to 7 as it would destroy the ABI for 
existing klds. 

-- 
John Baldwin