[julia-users] Huge performance boost with USE_SYSTEM_LIBM=1

[John Travers]

For a function which contains many calls to exp, sin, cos I got about a 4x 
performance boost by compiling with USE_SYSTEM_LIBM=1. Is this expected? 
Why exactly does Julia bundle and default to using its own libm? For 
consistency and accuracy? I'm on the latest MacBook Pro with a Haswell CPU 
- maybe this is to do with AVX?