which cputype for Althon 64 X2 Dual Core

Jeffrey Goldberg jeffrey at goldmark.org
Fri Dec 21 19:17:33 PST 2007

First of all, thank you very much for your response.  I have some  
follow up questions below.

On Dec 21, 2007, at 6:45 PM, Chuck Swiger wrote:

> On Dec 21, 2007, at 4:33 PM, Jeffrey Goldberg wrote:

>> What optimizations should I make in make.conf?
> A reasonable starting point is no special optimizations, and simply  
> disable debug options like WITNESS, INVARIANTS, etc.

I didn't see mention of these in the example make.conf so I don't know  
how to disable those if they are enabled in the first place.

> If you plan to go beyond that, you'll need to start by doing some  
> benchmarks [...]

I'm after the "low hanging fruit" and I don't really have the  
inclination to do such extensive tuning.  I was just wondering if  
there is anything obvious.

>> The example make.conf says
>> AMD64 architecture: opteron, athlon64, nocona, prescott, core2
>> But I don't know whether althon64 or core2 would be the safest and  
>> most appropriate.
>> Also GENERIC for amd64 lists
>>   cpu    HAMMER
>> is that the best (only) choice?
> Yes, as far as AMD64 code goes.  You could always switch down to  
> running in 32-bit mode, though.

That answer the question for the kernel configuration.  But what  
should I put in make.conf as cputype?  Right now, I've just left it  

I started a make buildworld and was surprised to see that it is using

   -O2 -fno-strict-aliasing -pipe

even though I didn't tell it to do so.  -O2 sounds like an odd default  
when it appears to be recommended against.

Where should I look for the defaults?



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