>> Now where does the "i686+SSE2" come into play? Does this SSE2 have any >> effect on those programs that do not contain SSE(2) related assembly code? >> Is this 1-2% improvement that you are mentioning only about these kind of >> programs (that do not contain assembly code)? > > One advantage of SSE2 is that it can be used as a replacement for the > braindead x87 (floating point) instructions. The x87 instructions are > architecturally stupid because they arrange the registers as a stack, > whereas what a compiler wants is a flat register file. > > There was an experimental branch of the OCaml/i386 compiler which used > SSE2 as a replacement for x87 instructions, and it gained a 10-15% > increase in performance *on floating point benchmarks* [1] (ie. not > just on any old code, and not code which used specific hand-written > SSE2 optimizations). > > (It's worth noting that SSE2 is always used on ocamlopt/x86_64) That's because its always been there on x86_64 and most people that care about performance have already moved to x86_64 to get the other performance benefits of 64 bit anyway. Peter -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
