From: Joel VanderWerf <vjoel@...>
Date: 2009-02-02T11:42:34+09:00
Subject: Re: Minor 1.8 <-> 1.9 performance comparison gotcha

M. Edward (Ed) Borasky wrote:
> On Sun, Feb 1, 2009 at 5:55 PM, Joel VanderWerf <vjoel@path.berkeley.edu> wrote:
>> M. Edward (Ed) Borasky wrote:
>>> 2. You should also take advantage of the GCC '-march=' and '-mtune='
>>> options and specify exactly what kind of processor(s) you have.
>> http://gcc.gnu.org/gcc-4.2/changes.html says:
>>> -mtune=native and -march=native will produce code optimized for the
>>> host architecture as detected using the cpuid instruction.
>> Has anyone tried this with ruby?
> 
> I have done it, but not recently. It's pretty easy to do. For example,
> on my Linux Athlon64 X2:
> 
> cd <ruby-source>
> export CFLAGS='-O3 -march=athlon64 -mtune=athlon64'
> ./configure
> make
> make test # be sure the compiler didn't break something!!!
> make benchmark # 1.9.x only!
> sudo make install

What about

CFLAGS='-O3 -march=native -mtune=native'

I was assuming that's how the new feature in gcc 4.2 works (only got 4.1 
here at the moment).

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407