Goroutines are one of Go’s most celebrated features. They make concurrency feel effortless — just add the go keyword and suddenly your program runs concurrently.

But what really happens after that single keyword?

In this talk we will explore the internals of Go’s concurrency runtime and uncover the real cost of goroutines. We will follow the journey of a goroutine from creation to execution and examine how the Go scheduler multiplexes thousands of goroutines onto a small number of OS threads.

Topics covered include:

* The G-M-P scheduler model
* Stack growth and stack shrinking
* Work stealing and scheduling queues
* Syscalls and scheduler parking
* Preemption and cooperative scheduling
* Debugging goroutine leaks
* Real production pitfalls with goroutines

Using real examples and runtime tracing tools, we will visualise how goroutines move through the scheduler and learn how design decisions in Go affect performance and scalability.

Attendees will leave with a deeper mental model of Go’s concurrency runtime and practical techniques for building high-performance concurrent systems.