Will C++/CLI + C++ Native increases performance? [closed]

Question

In our project we have three modules. C++ (Native), C++/CLI, C#. We are using C++/CLI to use C++(Native) code in C#. For this we are statically linking C++(Native) with C++/CLI, and now we can use C++/CLI managed dll with C#.

Now, code in C++(Native) is simple mathematics algorithms (No Win32, no interaction with OS). When I link static lib with C++/CLI, will it not become managed code? Means will it not come under CLR.

Does using C++(Native) static lib with C++/CLI in C# increases my performance? Can I not achieve writing code in C# itself rather than native code.

Kindly note, we have used algorithms,containers and iterators of standard C++ library extensively in our C++(Native) code.

Thanks.

Answer 1

When I link static lib with C++/CLI, will it not become managed code? Means will it not come under CLR.

No, not necessarily. In C++/CLI, all managed types will be compiled to MSIL and the code will run under the CLR. Native types are either compiled to MSIL or native machine code, depending on your compiler options:

• The /clr option generates a mixture of native and managed code.
• The /clr:pure option generates a managed-only assembly that can contain native types compiled to MSIL. This works basically like C# code compiled with the /unsafe option.
• The /clr:safe option generates a managed-only assembly that contains no native code. This works basically like C# code compiled without the /unsafe option.

Does using C++(Native) static lib with C++/CLI in C# increases my performance? Can I not achieve writing code in C# itself rather than native code.

Like all optimization questions, the answer is that it depends. On the one hand, native code is often faster than managed code and can be more highly optimized (e.g. with the use of SIMD). On the other hand, there is a performance hit associated with mixed-mode assemblies. The C++ interop implementation is usually quite fast (certainly much faster than P/Invoke from C#), but if the gains you're getting from compiling to native code are not substantial enough, it may still not be worth it. The only way to really know is to test the two options.

Managed code often gets a bad rap, especially from seasoned C++ programmers, but the truth is that well-written C# code can be just as fast if not faster than the equivalent native C++ code. It's also a lot easier to shoot yourself in the foot in C++, so if you've got a team of developers who are C# experts and not necessarily C++ experts, you're likely to end up with poorly-written and slower C++ code. Finally, when the rest of your project is all in C#, the decreased maintenance costs may mean that even similar performance is acceptable.