Audioslave - 7M3 - Live wrote: > > Bill Nottingham wrote: > > Audioslave - 7M3 - Live (creed7m3live@xxxxxxxxxxxxxxx) said: > > > > > I hope that the programs start to be compiled for at least 586 > > > and higher applications. (maybe more efficient programs) > > > > No. Compiling for i586 hurts you on *every* other processor > > variant. > > I can understand all processors being able to understand the i386 > instructions. I don't understand why the other variants cannot > understand the i586 or newer sets. Other Processors do not understand the newer *Intel* instructions (as Intel processors do not understand the new instructions AMD introduced). Remember that some Intel instructions *cannot* be used by other manufacturers because Intel holds patents on them! > The other distro installed and is compiled with i586 optimization. > Red Hat wouldn't even get past the disk integrity checks, on that > machine. What do you call "optimization"? -mach or -mcpu? > > The binaries are already tuned for i686; they just don't use > > i686-specific instructions except in some few cases where it > > actually helps. > > I take it that there were a lot of benchmark tests to determine that > there was no substantial gains in performance. With experimenting > with the kernel a bit. I did see that compiling with MMX didn't lead > to any gains. It seemed, but was not timed, to be slower with that > particular optimization. The MMX instructions are only useful for certain graphics and multimedia operations (for more information see Intel's white paper), for programs which have no use for these instructions they only are additional unneeded stuff to carry along. Most of the newly introduced instructions are useful only for special purposes. So in most cases it not only doesn't make any sense to use these new instructions, it is even bad! Furthermore, most of the really low-level functionality is provided by the kernel and glibc, and both are available for several processor types. Nearly all regular applications will gain *nothing* from using the new instruction sets. Red Hat does the Right Thing (TM). > Do the processors have to shift into different modes for each set of > instructions? Or are the sets of instructions accessable, equally, > with all of the different built-in sets? A processor supports certain instructions. There are no different modes. As long as the processor understands the instructions of which the binary is made of, the binary will run. If just one instruction in the binary is not understood by the processor, the binary will crash. Best regards, Martin Stricker -- Homepage: http://www.martin-stricker.de/ Linux Migration Project: http://www.linux-migration.org/ Red Hat Linux 8.0 for low memory: http://www.rule-project.org/ Registered Linux user #210635: http://counter.li.org/ -- Shrike-list mailing list Shrike-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/shrike-list
