On Tue, Jun 16, 2009 at 09:33:22PM -0400, Orcan Ogetbil wrote: > 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) Rich. [1] http://caml.inria.fr/pub/ml-archives/caml-list/2009/05/781b091ad8006b117f8554014826665e.en.html -- Richard Jones, Emerging Technologies, Red Hat http://et.redhat.com/~rjones libguestfs lets you edit virtual machines. Supports shell scripting, bindings from many languages. http://et.redhat.com/~rjones/libguestfs/ See what it can do: http://et.redhat.com/~rjones/libguestfs/recipes.html -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
