Tracing C++ function performance live via instrumentation [video]

Hello, since some time now I develop an extension for Visual Studio that makes it possible to see what's going on in your program live. This includes which code paths are executed and what changes in variables take place on each line of the function. Here, I decided to create a prototype that makes it possible to visualize the longest executing lines in the function, also completely live and at runtime.

The difference between this and e.g profilers like Tracy is that there's no need to insert the instrumentation manually, and you can explore the codebase much more freely to see what's going on. This is done through dynamic function relocation and inserting an rdtsc call after each line to collect the CPU timestamps. There's some more supporting code of course, but when it comes to overhead we get about ~15 instructions per line (more if it supported multiple threads).

On top of all that, the extension works really hard not to disrupt any standard Visual Studio workflow like setting breakpoints or viewing the call stack, which has been a very hard thing to achieve: the VS debugger expects that all code is on the same place as it was and that it maps perfectly to the corresponding debug information (which is not at all the case when the extension is running!).

If you want to try out the extension: https://d-0.dev/

I'm also active on a Discord server for the project if you want to talk more/follow for more updates: https://discord.gg/PY6X3NMmuN