Quote Originally Posted by savantu View Post
You've shown the worst example for HT. Linpack uses Intel libraries which are assembler optimized, you cannot get any higher efficiency than Linpack on CPUs; obviously HT has nothing to help here.
i showed you exactly what i intended: hyperthreading causing negative performance. nice straw man though. here are some more.

ASM optimizations are usually not that useful. the compilers designers know way more about optimizations than programmers (it's a big part of their job). they know when x87 is faster than SSE, what fp instructions have higher accuracy, what instruction have lowest latency, etc. well written source code with inline assembly can be faster than pure ASM, with less bugs, development time and more portable. MKL is still a great lib though.