r300951 make buildworld duration 18h

[Alfred Perlstein]

It's too bad make(1) can't have a "max parallel jobs" for a particular 
directory.

I believe that some of the llvm build winds up using nearly a gig of RAM 
per compiled .c file, so when you are running 2 jobs at once, LLVM will 
swap like mad.

If we could add something under the llvm directory "max jobs = RAM/1GB" 
we could have much faster build worlds.

-Alfred

On 5/30/16 7:43 AM, Kurt Jaeger wrote:
> Hi!
>
>> Yesterday I pulled via svn co ... a fresh r300951 and started the
>> buildworld as
>>
>> # make -j2 buildworld
>>
>> it ended today at lunchtime after 18 hours. The laptop has
>> 2x Intel Atom 1.6GHz and 1 GByte RAM and was otherwise unused.
>> Is this the normal buildworld time of today?
> Yes, this sounds in line with similar setups.
>
>> I think it spent most of the time in building the llvm...
> Yes, llvm is a real hog.
>
> That's why I normally build on amd64 boxes...
>