On 1/13/06, Raphael Melo de Oliveira Bastos Sales <[EMAIL PROTECTED]> wrote: > Actually, mmx doesn't really mean anything: > > http://en.wikipedia.org/wiki/MMX > > mplayer and the X server gain performance by using these extensions > (mmx, sse, sse2). One of the reasons why X is much faster in Gentoo > than in Debian. (Personal Experience, please, no flames)
Yes, MMX is quite an improvement if actually used in code. I once had to squeeze microseconds out of some windows code that I was writing, in order to speed up RS232 communication, and it made a HUGE difference. The code was originally taking a few ms, but I got it down to a few hundred microseconds by using MMX. MMX can operate on 64bit integers, where standard IA32 instructions can only operate on 32bit integers. > > 2006/1/13, John Myers <[EMAIL PROTECTED]>: > > On Friday 13 January 2006 07:45, Francesco Riosa wrote: > > > Tom Smith wrote: > > > > Well, if they're /not/ mutually exclusive, another question that comes > > > > up is... > > > > > > > > If a program is compiled with sse or sse2 support on a Pentium II, will > > > > the program run slower than it otherwise would? (Some of the programs I > > > > have are compiled and then distributed to servers with different > > > > CPUs--P-IIs and P-IVs, mainly.) > > > > > > speaking of manually added options to CFLAGS*, not of use flags > > > > > > The only place where mathematics count on a server is encryption ? > > > (notice the question mark) > > > Mayor part of server software use integer math that are not so enhanced > > > by optimizations. > > > The code produced is less stable, and difficult to debug, this bring to > > > the > > > question: why take the risk ? > > actually, mmx (MultiMedia eXtensions) , sse and sse2 instructions are > > designed > > primarily for multimedia and gaming type applications, which _do_ use > > floating-point math, and AFAIK, encryption is going to be all-integer too > > (floating-point math is not perfectly precise) > > > > And, like I said earlier, if you put a program with an sse or sse2 > > instruction > > on a PII, the program will most likely spontaneously abort when it tries to > > execute the unsupported instruction. > > -- > > # > > # electronerd, the electronerdian from electronerdia > > # > > > > > > > > -- > gentoo-user@gentoo.org mailing list > > -- gentoo-user@gentoo.org mailing list
