Producer-Consumer¶
One or more producers generate work; one or more consumers process it, through a shared, bounded buffer that coordinates the handoff. The pattern underneath almost every queue, pipeline, and streaming system covered elsewhere in this tree, at its smallest, single-process scale.
flowchart LR
Junior["Junior: the shared buffer and why it must be bounded"] --> Middle["Middle: implementing it with a condition variable"]
Middle --> Senior["Senior: multiple producers/consumers and starvation"]
Senior --> Professional["Professional: producer-consumer at scale - lock-free ring buffers"]
flowchart LR
Producer1[Producer] --> Buffer["Bounded buffer\n(shared, synchronized)"]
Buffer --> Consumer1[Consumer]
Choose a level¶
| Level | Guide | You are done when |
|---|---|---|
| Junior | The shared buffer | You can explain why an unbounded buffer between a fast producer and slow consumer is dangerous. |
| Middle | Implementing with a condition variable | You can implement a correct bounded buffer using a mutex + condition variable. |
| Senior | Multiple producers/consumers | You can explain how starvation can occur with multiple consumers competing for work. |
| Professional | Lock-free ring buffers at scale | You can explain how a single-producer-single-consumer ring buffer avoids locking entirely. |
Practice rule¶
Before implementing a producer-consumer buffer, ask: "what happens when the buffer is full and a producer tries to add more, or empty and a consumer tries to take?" Both cases need an explicit, correct wait mechanism — get either wrong and you have a busy-wait or a deadlock.