make.conf and building multiple kernels and worlds
Pieter de Goeje
pieter at degoeje.nl
Wed Jan 10 09:04:39 UTC 2007
On Tuesday 09 January 2007 17:21, Jonathan Horne wrote:
> i am finally looking at make.conf and how editing it could improve my
> 1) does specifying a cpu architecture really help?
It depends, but generally: yes. (although the perceived speed increase is
It really helps when you are using programs which use a lot of floating point
operations. gcc is then able to use the faster sse2 instructions instead of
plain x87 instructions.
> 2) if i am building for a p4-540 (nacona?), a p3, and a p4-xeon, what
> problems am i setting myself up for by specifying a cpu type on my build
You should choose the lowest common denominator: the p3 in this case. You'll
run into trouble if you build programs for a new processor and then run them
on an old one.
> at this point, im wondering how to go about building for more than one
> architecture effectively. right now, i build one world, and 3 different
> kernels, but they are all build with generic options.
> just wondering how i can effectivly leverage my build server to have the
> best compile options for my target boxes.
> any suggestions?
The kernel probably won't be any faster, but in any case here's how:
#make CPUTYPE=pentium4 buildkernel
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