We have been using an old version of the Intel Fortran Compiler, Professional Edition 11.1 for Linux, on Ubuntu 12.04LTS installed on a Xeon CPU with an Intel server since 2011. Now we have upgraded our server to a E5-2600 V4 Xeon based Intel server and installed Ubuntu 16.04LTS with Fortran Intel Parallel Studio XE Composer Edition for Fortran, for Linix version 17.0.
Our problem is that when we recompile our Fortran code on the new server with the new compiler (17.1) it runs drastically slower compared to when we run the older statically linked executable (compiled on the old server using Fortran 11.1). The old executable runs 20% faster on the new server which is the speed improvement we excepted due to the hardware upgrade. However, that speed improvement is completely lost if we recompile our code with the new 17.1 compiler on the new server.
We have tried optimization levels 01 and 03 but they don't help performance.
Any suggestions would be helpful.
Are there older versions of the compiler we can try and if yes where can we download them?
Please provide a test case we can build and run, along with the compile options you used. I'd recommend doing this through Intel Premier Support. See https://software.intel.com/en-us/articles/older-version-installation/ for downloading older versions.