Swift VS C# benchmarks

Current benchmark data was generated on Sun Jul 13 2025, full log can be found HERE

CONTRIBUTIONS are WELCOME!

[x86_64][4 cores] AMD EPYC 7763 64-Core Processor (Model 1)

* -m in a file name stands for multi-threading or multi-processing

* -i in a file name stands for direct intrinsics usage. (Usage of simd intrinsics via libraries is not counted)

* -ffi in a file name stands for non-stdlib FFI usage

* (You may find time < time(user) + time(sys) for some non-parallelized programs, the overhead is from GC or JIT compiler, which are allowed to take advantage of multi-cores as that's more close to real-world scenarios.)

binarytrees

Input: 18

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
csharp 1.cs 931ms 8.3ms 181.9MB 933ms 137ms dotnet 9.0.302
csharp 1.cs 942ms 11ms 168.9MB 943ms 137ms dotnet/aot 9.0.302
csharp 1.cs 1685ms 22ms 103.4MB 1870ms 203ms mono 6.12.0
swift 1.swift 2692ms 22ms 53.8MB 2657ms 20ms swift 6.1.2

Input: 15

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
csharp 1.cs 118ms 10ms 31.4MB 80ms 27ms dotnet/aot 9.0.302
csharp 1.cs 141ms 3.1ms 44.2MB 120ms 13ms mono 6.12.0
csharp 1.cs 191ms 3.1ms 51.1MB 157ms 30ms dotnet 9.0.302
swift 1.swift 240ms 0.7ms 11.9MB 230ms 0ms swift 6.1.2

fannkuch-redux

Input: 11

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
swift 1.swift 2463ms 7.5ms 5.5MB 2453ms 0ms swift 6.1.2

Input: 10

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
swift 1.swift 213ms 2.3ms 5.5MB 200ms 0ms swift 6.1.2

fasta

Input: 2500000

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
csharp 5-m.cs 127ms 6.3ms 25.3MB 360ms 83ms dotnet/aot 9.0.302
swift 3-m.swift 139ms 1.6ms 20.7MB 400ms 3ms swift 6.1.2
csharp 5-m.cs 191ms 3.3ms 37.6MB 470ms 120ms dotnet 9.0.302
csharp 5-m.cs 241ms 16ms 47.5MB 667ms 120ms mono 6.12.0

Input: 250000

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
csharp 5-m.cs 26ms 1.6ms 16.6MB 37ms 17ms dotnet/aot 9.0.302
swift 3.swift 37ms 0.3ms 14.2MB 30ms 0ms swift 6.1.2
csharp 5-m.cs 62ms 1.9ms 37.9MB 90ms 13ms dotnet 9.0.302
csharp 5-m.cs 71ms 2.1ms 30.6MB 103ms 20ms mono 6.12.0

helloworld

Input: QwQ

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
swift 1.swift 2.4ms 0.1ms 5.6MB 0ms 0ms swift 6.1.2
csharp 1.cs 6.3ms 0.2ms 9.4MB 0ms 0ms dotnet/aot 9.0.302
csharp 1.cs 33ms 1.2ms 21.3MB 20ms 0ms mono 6.12.0
csharp 1.cs 35ms 1.0ms 26.0MB 20ms 8ms dotnet 9.0.302

knucleotide

Input: 2500000_in

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
csharp 6-m.cs 459ms 14ms 46.3MB 1217ms 20ms dotnet/aot 9.0.302
csharp 6-m.cs 748ms 18ms 68.5MB 2110ms 23ms dotnet 9.0.302
csharp 6-m.cs 1011ms 2.7ms 66.6MB 2913ms 20ms mono 6.12.0
swift 2-m.swift 1361ms 16ms 74.3MB 4960ms 37ms swift 6.1.2

Input: 250000_in

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
csharp 6-m.cs 91ms 6.2ms 34.7MB 153ms 13ms dotnet/aot 9.0.302
csharp 6-m.cs 178ms 6.7ms 57.0MB 263ms 30ms dotnet 9.0.302
csharp 6-m.cs 199ms 4.8ms 55.2MB 377ms 20ms mono 6.12.0
swift 2-m.swift 251ms 2.0ms 60.0MB 663ms 30ms swift 6.1.2

nbody

Input: 5000000

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
swift 7.swift 346ms 2.1ms 9.9MB 337ms 0ms swift 6.1.2
csharp 9.cs 368ms 4.8ms 27.9MB 340ms 7ms dotnet 9.0.302
csharp 8.cs 372ms 3.5ms 9.9MB 357ms 0ms dotnet/aot 9.0.302
csharp 8.cs 419ms 3.4ms 27.9MB 403ms 7ms dotnet 9.0.302
csharp 8.cs 1250ms 3.2ms 22.1MB 1233ms 0ms mono 6.12.0

Input: 500000

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
swift 7.swift 39ms 0.9ms 9.9MB 30ms 0ms swift 6.1.2
csharp 8.cs 46ms 1.1ms 9.9MB 40ms 0ms dotnet/aot 9.0.302
csharp 9.cs 91ms 0.6ms 28.3MB 73ms 7ms dotnet 9.0.302
csharp 8.cs 97ms 3.8ms 27.6MB 80ms 7ms dotnet 9.0.302
csharp 8.cs 165ms 0.7ms 22.6MB 150ms 0ms mono 6.12.0

pidigits

Input: 8000

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
csharp 1.cs 3220ms 22ms 14.0MB 3130ms 93ms dotnet/aot 9.0.302
csharp 1.cs 3571ms 43ms 38.0MB 3593ms 117ms dotnet 9.0.302
swift 1.swift timeout 0.0ms 7.3MB 4927ms 60ms swift 6.1.2

Input: 4000

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
csharp 1.cs 753ms 1.0ms 13.3MB 720ms 27ms dotnet/aot 9.0.302
csharp 1.cs 993ms 5.8ms 37.9MB 1077ms 40ms dotnet 9.0.302
swift 1.swift 1865ms 11ms 7.0MB 1853ms 0ms swift 6.1.2