Alan Cox wrote: >> 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. > You see things I don't. Running mail and news servers on identical hardware with 12GB RAM I see about 4% difference in articles/sec. This is a serious but not extreme load, so it really is working a little faster in x86_64, but not 20%. If you mean 20% on some CPU bound number cruncher, that might be true, I no longer run loads like that for money, and haven't for years out of curiousity. > 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 ;)] > You mean booting an encrypted disk with LUKS from an encrypted device created in qemu-img? I do have some interesting clients... And I do run my desktop in a VM, WFM. -- Bill Davidsen <davidsen@xxxxxxx> "We have more to fear from the bungling of the incompetent than from the machinations of the wicked." - from Slashdot -- 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
