On Sun, 2009-12-13 at 13:53 -0500, Tom Lane wrote: > Paul Jakma <paul@xxxxxxxxxx> writes: > > On Wed, 18 Nov 2009, Roland McGrath wrote: > >> x86 is unlike other architectures because 64-bit also has twice as > >> many registers as 32-bit. So you get to trade off the benefits of > >> register allocation across more registers against the memory/cache > >> footprint of 64-bit pointers. > > > For what percentage of code is that an appreciable advantage? > > Pretty much everything, actually. The x86 ISA completely sucks. Indeed. Paul, take a look at the Intel 64 ISA and you'll see it's a very different beast. Intel fixed a lot of the issues with the (more than 20 year old really x86 ISA) and it's not simply a doubling of memory footprint because variable width instructions are used in the first place, and continue to be used in the newer ISA upgrade. Personally, I think anyone running i386 on x86_64 who isn't doing some kind of testing under KVM or similar is completely wasting their computing resources and should receive a free copy of the Intel documentation for the holidays ;) Jon. -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
