CppCon 2026

At scale, writing C++ becomes a different engineering discipline. Problems that appear secondary in smaller systems — dependency boundaries, build graph stability, toolchain inconsistencies, integration latency, ownership, and deployability — become first-order constraints.

In production HFT, a single core infrastructure repository may contain 26+ million lines of C++ across 100K files, organized into 250+ distinct subprojects: exchange gateways, feed handlers, protocol codecs, shared risk libraries, replay frameworks, and strategy infrastructure. That shared foundation is continuously modified, rebuilt, tested, and deployed by engineering teams across five time zones and more than 40 trading teams, each maintaining their own siloed multi-million-line client systems in C++, Rust, and Python.

Under these conditions, many accepted “best practices” simply do not survive contact with reality. Systems must instead evolve toward what might be called a ground state: components reduced to their essential boundaries and responsibilities, abstract enough to support radically different workloads, but precise enough to compose into a coherent whole.

The challenge is not merely writing fast code. It is building systems that remain correct, flexible, and evolvable while operating under constant latency and operational pressure.

This is not a talk about “perfect architecture,” but about the tradeoffs, hard-earned lessons, constraints, and occasional failures through which generations of engineers — myself included — have kept large systems moving forward without stopping the business behind them.

Your system has interchangeable strategies chosen at runtime, but the hot path runs millions of times per second. Runtime polymorphism has virtual dispatch overhead. Templates give you performance but lock you at compile time.

This workshop shows how to leverage inheritance for extensibility while avoiding vtable overhead, using a layered architecture of compile-time patterns. We'll build them up through OpenJDK's GC barrier system, where different GC algorithms compose different barriers on one of the hottest paths in the JVM.

We will also discuss trade-offs against alternatives like std::variant, function pointers, and plain virtual dispatch throughout. No JVM knowledge required.