math - Optimize mathematical library (libm) -


have tried compile glibc -march=corei7 see if there's performance improvement on version comes default linux x68_64 distribution? gcc compiled -march=i686. think (not sure) mathematical library compiled same way. can confirm this?

most linux distributions x86 compile using i686 instructions, asking scheduling them later processors. haven't followed later developments.

a long while different versions of system libraries according processor lines common, performance differences deemed small cost. , machines got more uniform in performance meanwhile.

one thing has remembered today's machines memory bound. i.e., today memory access takes few hundred times longer instruction, , gap growing. not mention machine (an oldish laptop, top-of-the-line 2 years back) has 4 cores (8 threads), battling data/instructions memory. making code run tiny bit faster, cpu can wait longer ram, isn't productive.


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