🌀 GoSchedulerSim

A playful simulation of Go's internal runtime scheduler, written in pure Go — featuring:

• M:P:G model (OS threads, processors, goroutines)
• Network polling simulation
• Work stealing between processors
• Preemption for long-running goroutines
• Blocking syscalls and resuming

Inspired by the real Go scheduler, built to learn and explore how concurrency works under the hood.

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✨ Features

• Simulates:
  • M (OS kernel threads)
  • P (logical processors with run queues)
  • G (goroutines / lightweight tasks)
• Network poller that injects tasks at random
• Handling blocking syscalls (with goroutines moving to a blocked queue)
• Simple round-robin binding of threads to processors
• Work stealing across processors to balance load
• Preemption: if a goroutine runs too long, it’s put back into the queue

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📦 Project Structure

type Scheduler struct { ... }
type OSThread struct { ... }
type Processor struct { ... }
type Goroutine struct { ... }

func (s *Scheduler) Start()
func (s *Scheduler) Go(task Task)
func (s *Scheduler) RunMachine(...)
...

All the logic lives in the internal package, written in idiomatic Go.

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🚀 Usage

Clone and run as a simple experiment or base for deeper exploration.

git clone https://github.com/omniflare/go-routine-scheduler
cd go-routine-scheduler
go run cmd/main.go

Inside main.go you can find:

	scheduler := internals.NewSchedler(2, 3)

	scheduler.Start()
	for i :=range 10 {
		scheduler.GO(func() {
			fmt.Printf("GOROUTINE %d running...\n", i)
			time.Sleep(50 * time.Millisecond)
		})
	}
	time.Sleep(5 * time.Second)

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🎓 Why?

This project is a learning experiment to understand how the Go scheduler manages thousands of goroutines efficiently — and to see how concepts like preemption, work stealing, and network polling look in code.

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📕 Sources

https://github.com/golang/go/blob/master/src/runtime/proc.go

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❤️ Contributing

Feel free to fork, explore, add features (e.g., priority scheduling, dynamic P/M management) and open PRs!

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