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++.
