Lock Contention

Noun · Development

Definitions

  1. A performance bottleneck that occurs when multiple threads frequently compete for the same lock, causing them to block and wait instead of doing useful work. High contention on a hot lock can serialize an otherwise parallel workload, destroying throughput.

    In plain English: When too many threads are fighting over the same lock at once, causing them to spend most of their time waiting instead of working.

    Example: "The flame graph shows 60% of wall time is threads blocked on lock contention around the global request counter — we need to shard it."

Related Terms