If you don’t feel like installing the CTP, no worries, just follow along. After installing it you can select this platform toolset from the project properties in the General section, as shown to the right. Since constexpr is not natively supported in Visual Studio 2013 I had to install the Visual C++ Compiler November 2013 CTP which contains new C++11 and C++14 features.
Driving fail compilation 2014 how to#
I previously blogged about how to use templates to do slow compiles but the template technique is quite finicky, and the thousands of types that it creates cause other distracting issues, so all of my measurements are done using the constexpr solution (thanks Nicolas). It is a toy project but it was constructed to simulate real issues that I have encountered on larger projects.Įach source file calculates a Fibonacci value at compile time using a recursive constexpr function so that the 56 byte source files take a second or two to compile. My test project consists of 21 C++ source files. After fixing some configuration errors this further dropped to 8.4 s. After turning on parallel builds this dropped to about 22 s. Spoiler alert: my test project started out taking about 32 s to build. Update, December 2019: the VC++ compiler now emits ETW events to make understanding build performance easier. And, as a geeky side-effect, I’ll explain some details of how VC++’s parallel compilation works.
I will also show how to avoid some of the easy mistakes that can significantly reduce VC++ compile parallelism and throughput. I want to show how, on a humble four-core laptop, enabling parallel compilation can give an actual four-times build speed improvement.
Visual Studio supports parallel compilation but it is poorly understood and often not even enabled. The free lunch is over and our CPUs are not getting any faster so if you want faster builds then you have to do parallel builds.
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