[dundarious]

The relevant part were our model calculations and it was already heavily optimized (no allocations, etc.), so none of the new library stuff would help at all. We just found that Linux .NET Core underperformed compared to Windows .NET anything (Framework or Core). Maybe our methodology was wrong, but we had a few people look at it, made the comparison in several ways, and generally tried to be quite thorough. We always found Linux (only .NET Core) had ~0.9x the performance of Windows (any .NET) — and we were a mostly Linux shop, running C/C++ apps, so our Linux build was appropriately tuned. Given .NET Core was relatively new at the time, and Framework still had some legs, we didn’t dig down as far as looking at IR or JIT output, because we could afford to wait. After all, one of the draws was to reduce problems due to using our fancy network cards+stack in Windows, so there was no point in adding complexity from a new Linux .NET runtime, including complexity from having to troubleshoot performance.

I’ve been saying “we”, but I left that job a couple years ago so I won’t be trying any new .NET versions myself :-)