Parallelism is hard. So until recently, TinyGo (the alternative Go compiler for small systems) simply did not implement it. Instead, we used a simple single threaded scheduler that provides concurrency, but not parallelism. This made all programs act like GOMAXPROCS=1, which caused some practical issues.

Over the past few months we added support for running multiple goroutines in parallel on Linux, MacOS, and on the dual-core RP2040 chip. This required changes in many parts of TinyGo that previously assumed single threaded operation.

This talk will cover a variety of topics that may be interesting to anybody who wants to learn about low level primitives:

• Which parts of Go are affected by parallelism.
• Futexes: the building block of concurrency primitives on modern operating systems.
• How some synchronisation primitives like channels and sync.Mutex are implemented in TinyGo.
• How parallelism is implemented in TinyGo on Linux, MacOS, and the RP2040 chip.