Goroutine lifecycle - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a goroutine in Go?

A goroutine is a lightweight thread managed by the Go runtime. It allows functions to run concurrently without the overhead of traditional threads.

intermediate

What are the main states in a goroutine's lifecycle?

The main states are:

• Created (ready to run)
• Running (actively executing)
• Waiting (blocked on I/O, channel, or synchronization)
• Dead (finished execution)

intermediate

How does a goroutine transition from waiting to running?

When the event it waits for completes (like data on a channel or a timer), the goroutine is moved from waiting to ready, then scheduled by the Go runtime to run.

beginner

What happens when a goroutine finishes its function?

It enters the dead state and is cleaned up by the Go runtime. It no longer consumes CPU or memory resources.

intermediate

Why are goroutines considered lightweight compared to OS threads?

Because goroutines use small stacks that grow and shrink dynamically and are multiplexed onto fewer OS threads by the Go scheduler, making them efficient to create and manage.

Which state is NOT part of the goroutine lifecycle?

A Sleeping

B Running

C Waiting

D Dead

Goroutines do not have a 'Sleeping' state; they are either running, waiting (blocked), or dead.

What triggers a goroutine to move from waiting to running?

A Completion of the event it waits for

B Manual restart by the programmer

C Garbage collection

D Timeout expiration only

When the awaited event (like channel data or timer) completes, the goroutine becomes ready to run.

How does the Go runtime manage many goroutines efficiently?

A By running goroutines sequentially

B By multiplexing goroutines onto fewer OS threads

C By pausing all goroutines periodically

D By creating one OS thread per goroutine

The Go scheduler multiplexes many goroutines onto a smaller number of OS threads to save resources.

What happens to a goroutine after it finishes execution?

A It goes back to waiting state

B It restarts automatically

C It enters the dead state and is cleaned up

D It becomes a zombie process

Finished goroutines enter the dead state and are cleaned up by the runtime.

Which of these is a reason goroutines are lightweight?

A They run only on a single CPU core

B They require a full OS thread each

C They cannot communicate with each other

D They use small, dynamically growing stacks

Goroutines use small stacks that grow as needed, making them lightweight compared to OS threads.

Describe the lifecycle of a goroutine from creation to termination.

Think about how a goroutine starts, waits, runs, and finishes.

Explain why goroutines are more efficient than traditional OS threads.

Consider resource use and scheduling.