From: engrbohn@aol.com (Engr Bohn) Newsgroups: comp.parallel.mpi Subject: Re: WINNT and UNIX Date: 10 Mar 1999 12:18:41 GMT Organization: AOL http://www.aol.com References: <36E55DC5.1B42A9F4@lhm.mw.tu-muenchen.de> Message-Id: <19990310071841.29267.00000438@ng109.aol.com> Xref: ukc comp.parallel.mpi:4724 On 3/9/99 12:43 PM Eastern Standard Time, "Martin F. Schuster" wrote: >Since I am >dependent on every >resource I can get, I was wondering, whether I could connect PCs >running WINNT 4.0 with >our SGI Indigo/Oxigene and IBM RS6000 workstations. I could imagine that >I'll >get in trouble with respect to the binary compatiblity of the the >different architectures. We've recently begun experimenting with PaTENT MPI for WinNT and MPICH 1.1.2 (requires source code modifications to MPICH) on Linux (both with Pentium IIs), and that's working fine. I don't recall off the top of my head whether the MIPS & PowerPC processors are big endian or little endian -- I also don't know whether MPI would correct for this, so I make no promises as to whether our experience with WinNT & Linux will extend to WinNT & SGI or IBM. >Optional I could run our PCs (Dual PII 330) under Linux, however I 've >had the experience >that WINNT's Visual Fortran Compiler, with its excellent optimization >routines, >generated 60% faster code. We've had similar experience (except with Visual C++ vs g++). There are two factors here. First is the default optimizations. MS's compilers default to maximum optimization, while the GNU compilers default to a lower optimization (-O0 IIRC -- no optimization). After specifiying optimization levels, we still found a performance difference. And we suspect that this is because the GNU compilers are general-purpose and will generate code for 386s & better. There is a group that has developed egcs-derived compilers optimized specifically for the Pentium or Pentium Pro/II/III (pgcc), available from http://www.goof.com/pcg -- we haven't tested the pgcc suite yet, though. Take care, cb Christopher A. Bohn EngrBohn@aol.com http://members.aol.com/EngrBohn/ "Oooh! What does >this< button do!?"