< iframe size =" 480" elevation =" 320" src =" https://www.youtube.com/embed/VzyhpbrC2Bs?rel=0" frameborder =" 0" allowfullscreen > Efficiency is just one of the chief reasons numerous C++ programmers enjoy the language. In the past, Moore's Law indicated that our programs ran much faster annually. Since Dennard scaling has actually ended, C++ developers need to work more challenging to obtain high efficiency for their applications. In this talk, I'll first talk about a few of the considerable as well as unusual difficulties facing C++ developers trying to attain high performance on modern-day equipment systems: efficiency is far less steady and also foreseeable than you could believe! I'll offer some experimental proof that highly suggests we can not count on compiler optimizations to aid us out of this hole: in specific, I'll reveal-- utilizing a brand-new speculative methodology-- that the difference between clang's -O2 as well as -O3 optimization degrees is basically tantamount from sound. Since compiler optimizations have actually run out of steam, we need much better profiling support, especially for modern concurrent, multi-threaded applications. I'll talk concerning a brand-new technique to profiling, which I call "causal profiling". Causal profiling lets developers optimize for throughput or latency, as well as which identifies and precisely forecasts the effect of optimizations. It functions by running efficiency experiments, based on the suggestion of "online speedups". We have actually built a causal profiler called Coz, which now ships as component of common Linux distros, and also which additionally benefits C++ and also Corrosion (there's even a Java version). Using it, we discover that Cousin can unlock formerly unknown optimization opportunities. Directed by Cousin, we enhanced the efficiency of Memcached (9%), SQLite (25%), and accelerated 6 various other applications by as high as 68%; for the most part, this entailed changing less than 10 lines of code as well as took under half a hr (without any prior understanding of the programs!). MAGAZINE APPROVALS: CppCon Organizer supplied Coding Tech with the authorization to republish CppCon computerese. CREDITS: CppCon YouTube channel: https://www.youtube.com/user/CppCon/videos