C# Asynchronous Libraries Benchmarks

This project is built to benchmark C# asynchronous libraries against each other.

These benchmarks are ran using BenchmarkDotNet.

This is a non-exhaustive benchmark of each library's features. It is only meant to compare the most common use scenario (awaiting an asynchronous result). Some libraries provide more/different features than others.

Asynchronous libraries benchmarked:

• Built-in callbacks (System.Action), measured as the baseline
• System.Threading.Tasks (TPL), Task and ValueTask
• ProtoPromise v3.5.0
• UniTask v2.5.10
• UnityFx.Async v1.1.0
• RSG Promises v3.0.1

To run the benchmarks on your machine:

1. Run RunAllBenchmarks.bat (or run a script individually for each runtime in the Scripts directory).
2. See your results in the generated Scripts/BenchmarkDotNet.Artifacts directory.

Note: Some functions are not actually supported in some libraries (like RSG does not support async/await), so they will show as NA or ?. Callbacks are measured the same for each benchmark as a baseline to compare against, and does not mean you can actually use async/await or ContinueWith with them.

ContinueWith is either using the .ContinueWith API or .Then API, depending on each library.

.Net 10.0 Benchmarks

BenchmarkDotNet v0.16.0-nightly.20251220.380, Windows 10 (10.0.19045.6466/22H2/2022Update)
AMD Ryzen 7 9800X3D 4.70GHz, 1 CPU, 16 logical and 8 physical cores
.NET SDK 10.0.100
  [Host]     : .NET 10.0.0 (10.0.0, 10.0.25.52411), X64 RyuJIT x86-64-v4
  DefaultJob : .NET 10.0.0 (10.0.0, 10.0.25.52411), X64 RyuJIT x86-64-v4

Type	Method	Pending	Mean	Ratio	Allocated	Pooled
AsyncAwait	Callback	False	42.28 ns	1.00	832 B	-
AsyncAwait	ProtoPromise	False	16.49 ns	0.39	-	-
AsyncAwait	RsgPromise	False	NA	?	NA	NA
AsyncAwait	Task	False	32.36 ns	0.77	192 B	-
AsyncAwait	UniTask	False	33.75 ns	0.80	-	-
AsyncAwait	UnityFxAsync	False	44.41 ns	1.05	360 B	-
AsyncAwait	ValueTask	False	33.21 ns	0.79	-	-
AsyncAwait	Callback	True	51.69 ns	1.00	832 B	-
AsyncAwait	ProtoPromise	True	326.92 ns	6.33	-	600 B
AsyncAwait	RsgPromise	True	NA	?	NA	NA
AsyncAwait	Task	True	405.42 ns	7.84	1120 B	-
AsyncAwait	UniTask	True	373.51 ns	7.23	-	720 B
AsyncAwait	UnityFxAsync	True	366.40 ns	7.09	1952 B	-
AsyncAwait	ValueTask	True	492.82 ns	9.53	1352 B	-
ContinueWith	Callback	False	42.34 ns	1.00	832 B	-
ContinueWith	ProtoPromise	False	78.77 ns	1.86	-	-
ContinueWith	RsgPromise	False	74.19 ns	1.75	1032 B	-
ContinueWith	Task	False	300.68 ns	7.10	1224 B	-
ContinueWith	UniTask	False	81.72 ns	1.93	-	-
ContinueWith	UnityFxAsync	False	238.66 ns	5.64	1304 B	-
ContinueWith	ValueTask	False	NA	?	NA	NA
ContinueWith	Callback	True	51.92 ns	1.00	832 B	-
ContinueWith	ProtoPromise	True	312.85 ns	6.03	-	312 B
ContinueWith	RsgPromise	True	790.59 ns	15.23	10104 B	-
ContinueWith	Task	True	527.94 ns	10.17	1864 B	-
ContinueWith	UniTask	True	522.47 ns	10.06	-	1272 B
ContinueWith	UnityFxAsync	True	364.54 ns	7.02	1560 B	-
ContinueWith	ValueTask	True	NA	?	NA	NA