core2 flag for arch on gcc 4.3.2

[Tim Prince]

tom gogh wrote:

>    I am planning to migrate my linux to 4.3.2 but, current flag for core 2 duo is nocona.
> I couldn't find elaborate explanation of core2 flag compare to nocona.
> What is difference between core2 and nocona flags?
> Do they behave identical or core2 offers better performance/tunning?

Not knowing where you're trying to go with this, default for 64-bit gcc is
 good for Core 2, from no difference up to 50% better throughput than
nocona in my tests.  -msse3 is available for either Nocona or Core 2 CPUs.
 You probably wouldn't want the nocona option even for the older CPU.  I
can't imagine why you don't simply try the options you have in mind, nor
do I understand what you mean by nocona being a current flag.  Maybe you
mean the best option for some old version of gcc which predates Core 2.
I don't think -mtune=barcelona is available until more recent versions of
gcc; it may often give better vectorization even on Core 2, particularly
for Fortran, maybe for C, not so much for C++.