flops

I've been asked to measure the performance of a fortran program that solves differential equations on a multi-CPU system. My employer insists that I measure FLOP/s (Floating operations per second) and compare the results with benchmarks ( LINPACK ) but I am not convinced that it's the way to go, simply because no one can explain to me what a FLOP is. I did some research on what exactly a FLOP is and I got some pretty contradicting answers. One of the most popular answers I got was '1 FLOP = An addition and a multiplication operation'. Is that true? If so, again, physically, what exactly does

A decade or two ago, it was worthwhile to write numerical code to avoid using multiplies and divides and use addition and subtraction instead. A good example is using forward differences to evaluate a polynomial curve instead of computing the polynomial directly. Is this still the case, or have modern computer architectures advanced to the point where *,/ are no longer many times slower than +,- ? To be specific, I'm interested in compiled C/C++ code running on modern typical x86 chips with extensive on-board floating point hardware, not a small micro trying to do FP in software. I realize

I'm confused on how many flops per cycle per core can be done with Sandy-Bridge and Haswell. As I understand it with SSE it should be 4 flops per cycle per core for SSE and 8 flops per cycle per core for AVX/AVX2. This seems to be verified here, How do I achieve the theoretical maximum of 4 FLOPs per cycle? ,and here, Sandy-Bridge CPU specification . However the link below seems to indicate that Sandy-bridge can do 16 flops per cycle per core and Haswell 32 flops per cycle per core http://www.extremetech.com/computing/136219-intels-haswell-is-an-unprecedented-threat-to-nvidia-amd . Can someone