Hi, On Sun 27 Jan 2002 08:23, [EMAIL PROTECTED] wrote: > On 26 Jan 2002, at 14:45, John R Pierce wrote: > > > http://www.slashdot.org has a link to http://open-mag.com on a new > > > Intel compiler for Linux an M$ Windows. The new compiler makes use of > > > the new instructions in the Pentium III and IV. Of course, the most > > > important part of the Prime95 code does not get compiled at all, since > > > it has already been handcoded. But it would be nice to know if a > > > recompile with this compiler would improve throughput significantly, > > > anyone? > > > > I believe the Intel C 5.0 compiler is based on Kai C++, which is hardly > > new. Its also $500 per user per system on Linux. The MS Windows version > > requires you to already have the MS Visual C++ 6.0 package, as this > > piggybacks on the MS C tools. This isn't going to take the open source > > world by storm... > > > [snip] > > Where such a compiler would make a difference is in porting code > to new or substantially different architectures; Glucas is already > pretty good on IA32/linux, but a compiler "upgrade" might help get > it a bit closer to Prime95. The difficulty with porting Prime95 to non- > IA32 architectures is that so much of it is in assembler, which is > not easy to port between architectures whilst retaining something > approaching optimum efficiency. In fact it would be pretty much a > total rewrite job. >
I've already used Intel 5.0 compiler for Glucas in both IA32 and IA64 architectures. For IA32, GNU/gcc does better job because of Glucas also has assembler macros in its code and Intel compiler has problems with them. So, I had to compile Glucas for PentiumIII (linux) deactivating the assembler code and the result was a code about 20% slower. As a proof, I also deactivate the assembler code in GNU/gcc compiler and the result was a bit slower (5%) than Intel in very big FFT runLengths. On IA64/linux Intel compiler clearly is the winner (about 30% faster than gcc job). Actually the last binaries for Glucas 2.8c/IA64 are built with it. Some other advantage of Intel compiler is the OpenMP compatibily. I used it to make Glucas OpenMP compatible, but then I also made it multithreaded using Posix Threads and GNU/gcc compiler. > As John points implies, you've got to be pretty committed to shell > out ~$500 per system for the privelege of compiling code on your > own hardware. It would take a _really_ significant speed boost to > make that sort of expenditure worthwhile. > I downloaded a free complete version for non-profit proposes from intel site. Have a nice Sunday Guillermo. -- Guillermo Ballester Valor [EMAIL PROTECTED] Granada (Spain) _________________________________________________________________________ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
