This library provides implementations of concurrent FIFO queues (for both
general boxed and primitive unboxed values) that are fast, perform well under
contention, and offer a Chan-like interface. The library may be of limited
usefulness outside of x86 architectures where the fetch-and-add instruction is
We export several variations of our design; some support additional
functionality while others try for lower latency by removing features or making
them more restrictive (e.g. in the 'Unboxed' variants).
'Unagi': a general-purpose near drop-in replacement for 'Chan'.
'Unagi.Unboxed': like 'Unagi' but specialized for primitive types; this may
perform better if a queue grows very large.
'Unagi.Bounded': a bounded variant with blocking and non-blocking writes, and
other functionality where a notion of the queue's capacity is required.
'Unagi.NoBlocking': lowest latency implementations for when blocking reads
'Unagi.NoBlocking.Unboxed': like 'Unagi.NoBlocking' but for primitive types.
Some of these may be deprecated in the future if they are found to provide
little performance benefit, or no unique features; you should benchmark and
experiment with them for your use cases, and please submit pull requests for
additions to the benchmark suite that reflect what you find.
Here is an example benchmark measuring the time taken to concurrently write and
read 100,000 messages, with work divided amongst increasing number of readers
and writers, comparing against the top-performing queues in the standard
libraries. The inset graph shows a zoomed-in view on the implementations here.