Dining Philosophers Deadlock Simulator (2D)

Table Setup

Philosophers 5

Sim speed 1.0×

Locking strategy

Live Readout

State

Running

Meals served

Holding 1 fork

Deadlocks hit

FPS

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How it works

Dijkstra's dining philosophers problem models a classic concurrency hazard: N processes each need two shared resources (forks) to make progress, and a resource can be held by only one process at a time. Each philosopher alternates thinking → waiting (trying to acquire both forks) → eating → thinking.

Naive — always grab the left fork, then the right. If every philosopher gets hungry at once, everyone holds their left fork and waits forever for a right fork held by their neighbour: a circular wait. That is deadlock.
Resource ordering — forks are numbered, and every philosopher must pick up the lower-numbered fork first. The highest-numbered philosopher then reaches for a different fork first than everyone else, breaking the circular chain.
Waiter / arbitrator — a central arbitrator allows only up to N−1 philosophers to attempt picking up forks at once, guaranteeing at least one can always finish and release forks for the rest.

Deadlock requires four conditions simultaneously: mutual exclusion, hold-and-wait, no preemption, and circular wait. Breaking just one — as resource ordering does to circular wait — makes deadlock structurally impossible.

⛔ DEADLOCK — every philosopher is stuck holding one fork

Thinking Waiting (1 fork) Eating Deadlocked