> Also, the ABI is much better, and this may be almost as significant. > > > Unfortunately that biggest gain only occurs if the program logic is such that > > registers run out often. > > Which, in the case of gcc-generated code, is most of the time. gcc > was originally written for, and still works best with, a machine with > 16 or more general-purpose registers. 32- bit x86 only has five or > six registers to play with, and this just isn't enough for good code > generation. I don't think that Java has it very much easier. The overall performance difference seems to be about 20% these days although of course very workload dependant. A 32bit kernel in particular really starts to hurt above 1GB RAM (actually about 900MB) and once you get towards 4GB the 32bit option becomes a complete waste. KVM in some ways makes the choice easier. If you are running lots of guests then its often a very good idea that your main desktop environment is itself a guest - for security and convenience reasons. That makes it easy to have a 32bit guest around, or even keep a 32bit 'internet' guest just for browsing etc and to keep anything of value and the internet further apart from each other. [Also of course means you can have several guests some using tunnels if you are paranoid about the black helicopters ;)] Alan -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
