OCaml VS Rust 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
rust 4.rs 1277ms 6.1ms 33.6MB 1253ms 10ms rustc 1.88.0
rust 5.rs 1404ms 46ms 33.8MB 1380ms 7ms rustc 1.88.0
rust 3.rs 1431ms 12ms 49.8MB 1400ms 13ms rustc 1.88.0
ocaml 1.ml 3087ms 52ms 157.2MB 3003ms 70ms ocaml 5.3.0

Input: 15

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 4.rs 122ms 2.6ms 5.6MB 110ms 0ms rustc 1.88.0
rust 5.rs 128ms 3.1ms 5.8MB 120ms 0ms rustc 1.88.0
rust 3.rs 137ms 3.2ms 7.8MB 127ms 0ms rustc 1.88.0
ocaml 1.ml 221ms 1.6ms 19.1MB 207ms 0ms ocaml 5.3.0

fannkuch-redux

Input: 11

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 3-im.rs 408ms 2.7ms 2.1MB 1570ms 0ms rustc 1.88.0
rust 5-m.rs 555ms 5.1ms 2.0MB 2160ms 0ms rustc 1.88.0
rust 2-im.rs 672ms 12ms 2.0MB 2567ms 0ms rustc 1.88.0
rust 1-m.rs 941ms 5.9ms 2.1MB 3617ms 0ms rustc 1.88.0
rust 3-i.rs 1506ms 1.0ms 1.9MB 1500ms 0ms rustc 1.88.0
rust 2-i.rs 2400ms 1.3ms 1.8MB 2390ms 0ms rustc 1.88.0
rust 1.rs 2723ms 24ms 1.8MB 2713ms 0ms rustc 1.88.0
ocaml 2.ml 2909ms 4.1ms 4.9MB 2903ms 0ms ocaml 5.3.0

Input: 10

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 3-im.rs 37ms 0.3ms 2.0MB 120ms 0ms rustc 1.88.0
rust 5-m.rs 52ms 0.9ms 2.1MB 170ms 0ms rustc 1.88.0
rust 2-im.rs 60ms 1.0ms 2.1MB 203ms 0ms rustc 1.88.0
rust 1-m.rs 81ms 1.2ms 2.1MB 290ms 0ms rustc 1.88.0
rust 3-i.rs 126ms 0.1ms 1.9MB 120ms 0ms rustc 1.88.0
rust 2-i.rs 198ms 0.3ms 1.8MB 190ms 0ms rustc 1.88.0
rust 1.rs 229ms 1.4ms 1.8MB 220ms 0ms rustc 1.88.0
ocaml 2.ml 245ms 0.8ms 5.2MB 237ms 0ms ocaml 5.3.0

fasta

Input: 2500000

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 6.rs 90ms 1.0ms 1.9MB 80ms 0ms rustc 1.88.0
rust 5c-m.rs 90ms 0.3ms 3.4MB 260ms 0ms rustc 1.88.0
rust 5-m.rs 91ms 0.4ms 3.2MB 273ms 0ms rustc 1.88.0
rust 1c.rs 161ms 0.2ms 1.9MB 150ms 0ms rustc 1.88.0
rust 1.rs 195ms 1.3ms 1.9MB 183ms 0ms rustc 1.88.0
ocaml 6.ml 346ms 1.9ms 24.8MB 330ms 0ms ocaml 5.3.0

Input: 250000

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 6.rs 11ms 0.4ms 1.9MB 0ms 0ms rustc 1.88.0
rust 5c-m.rs 15ms 0.6ms 3.4MB 23ms 0ms rustc 1.88.0
rust 5-m.rs 16ms 0.4ms 3.2MB 27ms 0ms rustc 1.88.0
rust 1c.rs 19ms 0.4ms 1.9MB 10ms 0ms rustc 1.88.0
rust 1.rs 22ms 0.5ms 1.9MB 10ms 0ms rustc 1.88.0
ocaml 6.ml 39ms 0.7ms 7.4MB 30ms 0ms ocaml 5.3.0

helloworld

Input: QwQ

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 1.rs 1.2ms 0.0ms 1.8MB 0ms 0ms rustc 1.88.0
rust 1.rs 1.2ms 0.1ms 1.9MB 0ms 0ms rustc 1.90.0-nightly
ocaml 1.ml 1.8ms 0.1ms 5.0MB 0ms 0ms ocaml 5.3.0

lru

Input: 1000 1000000

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 0-unsafe.rs 38ms 5.3ms 1.8MB 33ms 0ms rustc 1.88.0
rust 1.rs 51ms 5.5ms 1.9MB 43ms 0ms rustc 1.88.0
ocaml 1.ml 173ms 2.7ms 6.4MB 163ms 0ms ocaml 5.3.0

Input: 1000 3000000

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 0-unsafe.rs 136ms 6.3ms 1.8MB 127ms 0ms rustc 1.88.0
rust 1.rs 197ms 16ms 2.0MB 190ms 0ms rustc 1.88.0
ocaml 1.ml 532ms 18ms 6.6MB 520ms 0ms ocaml 5.3.0

Input: 100 500000

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 0-unsafe.rs 24ms 1.1ms 1.8MB 20ms 0ms rustc 1.88.0
rust 1.rs 30ms 1.2ms 1.8MB 20ms 0ms rustc 1.88.0
ocaml 1.ml 78ms 0.4ms 6.2MB 70ms 0ms ocaml 5.3.0

merkletrees

Input: 17

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 1.rs 712ms 1.1ms 33.8MB 690ms 10ms rustc 1.88.0
ocaml 1.ml 1077ms 22ms 70.2MB 1037ms 27ms ocaml 5.3.0
ocaml 2.ml 2068ms 35ms 91.8MB 2017ms 37ms ocaml 5.3.0

Input: 15

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
ocaml 1.ml 144ms 1.4ms 21.7MB 127ms 3ms ocaml 5.3.0
rust 1.rs 154ms 4.0ms 9.8MB 143ms 0ms rustc 1.88.0
ocaml 2.ml 359ms 6.4ms 27.7MB 340ms 7ms ocaml 5.3.0

nbody

Input: 5000000

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 4-i.rs 164ms 0.5ms 1.8MB 160ms 0ms rustc 1.88.0
rust 7-i.rs 219ms 0.6ms 1.8MB 210ms 0ms rustc 1.88.0
rust 1.rs 229ms 0.2ms 1.8MB 220ms 0ms rustc 1.88.0
rust 3.rs 279ms 0.6ms 1.9MB 270ms 0ms rustc 1.90.0-nightly
rust 2.rs 279ms 0.4ms 1.8MB 270ms 0ms rustc 1.88.0
ocaml 1.ml 374ms 2.6ms 5.2MB 367ms 0ms ocaml 5.3.0

Input: 500000

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 4-i.rs 19ms 0.1ms 1.8MB 10ms 0ms rustc 1.88.0
rust 7-i.rs 24ms 0.3ms 1.8MB 20ms 0ms rustc 1.88.0
rust 1.rs 25ms 0.4ms 1.8MB 20ms 0ms rustc 1.88.0
rust 3.rs 30ms 0.2ms 1.8MB 20ms 0ms rustc 1.90.0-nightly
rust 2.rs 30ms 0.3ms 1.6MB 20ms 0ms rustc 1.88.0
ocaml 1.ml 40ms 0.1ms 5.2MB 30ms 0ms ocaml 5.3.0

nsieve

Input: 12

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 2.rs 303ms 3.7ms 6.6MB 293ms 0ms rustc 1.88.0
rust 1.rs 377ms 18ms 40.9MB 363ms 0ms rustc 1.88.0
ocaml 1.ml 945ms 11ms 547.9MB 883ms 47ms ocaml 5.3.0
ocaml 2.ml 1884ms 7.1ms 17.2MB 1870ms 0ms ocaml 5.3.0

Input: 10

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 1.rs 68ms 4.3ms 11.6MB 57ms 0ms rustc 1.88.0
rust 2.rs 77ms 1.6ms 2.9MB 70ms 0ms rustc 1.88.0
ocaml 1.ml 178ms 0.8ms 142.3MB 153ms 10ms ocaml 5.3.0
ocaml 2.ml 464ms 1.5ms 9.3MB 453ms 0ms ocaml 5.3.0

regex-redux

Input: 2500000_in

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 7.rs 435ms 3.4ms 78.4MB 443ms 13ms rustc 1.88.0
ocaml 2.ml timeout 0.0ms 462.9MB 4830ms 157ms ocaml 5.3.0

Input: 250000_in

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 7.rs 51ms 0.9ms 11.6MB 43ms 0ms rustc 1.88.0
ocaml 2.ml 542ms 2.0ms 57.1MB 510ms 17ms ocaml 5.3.0

spectral-norm

Input: 8000

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 7-m.rs 493ms 0.6ms 2.1MB 1910ms 0ms rustc 1.88.0
rust 8-m.rs 494ms 0.2ms 2.5MB 1907ms 3ms rustc 1.90.0-nightly
rust 8.rs 992ms 1.9ms 2.4MB 983ms 0ms rustc 1.90.0-nightly
rust 7.rs 1924ms 0.5ms 1.9MB 1913ms 0ms rustc 1.88.0
rust 2-m.rs 2071ms 4.3ms 2.4MB 8133ms 3ms rustc 1.88.0
rust 2.rs 4270ms 7.1ms 2.0MB 4260ms 0ms rustc 1.88.0
ocaml 2.ml 4558ms 6.5ms 6.3MB 4543ms 0ms ocaml 5.3.0

Input: 4000

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 7-m.rs 127ms 0.2ms 2.3MB 470ms 3ms rustc 1.88.0
rust 8-m.rs 128ms 0.3ms 2.3MB 470ms 7ms rustc 1.90.0-nightly
rust 8.rs 250ms 0.4ms 2.1MB 240ms 0ms rustc 1.90.0-nightly
rust 7.rs 488ms 5.6ms 1.8MB 480ms 0ms rustc 1.88.0
rust 2-m.rs 521ms 0.5ms 2.1MB 2013ms 0ms rustc 1.88.0
rust 2.rs 1069ms 2.0ms 1.9MB 1060ms 0ms rustc 1.88.0
ocaml 2.ml 1146ms 5.3ms 6.1MB 1137ms 0ms ocaml 5.3.0

Input: 2000

lang code time stddev peak-mem mem time(user) time(sys) compiler compiler/runtime
rust 8-m.rs 36ms 0.6ms 2.3MB 110ms 0ms rustc 1.90.0-nightly
rust 7-m.rs 36ms 0.0ms 2.1MB 113ms 0ms rustc 1.88.0
rust 8.rs 65ms 0.6ms 1.9MB 60ms 0ms rustc 1.90.0-nightly
rust 7.rs 127ms 1.7ms 1.8MB 120ms 0ms rustc 1.88.0
rust 2-m.rs 134ms 0.2ms 2.1MB 500ms 0ms rustc 1.88.0
rust 2.rs 270ms 1.7ms 1.9MB 260ms 0ms rustc 1.88.0
ocaml 2.ml 296ms 9.1ms 5.2MB 287ms 0ms ocaml 5.3.0