The Computer Language
25.02 Benchmarks Game

Rust versus C clang

How the programs are written matters! Always look at the source code.

If the fastest programs are flagged * possible hand-written vector instructions or "unsafe" or naked ffi, does the host language matter? You might be more interested in the less optimised programs — more seconds, less gz source code.

fannkuch-redux      
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
* C clang #6 2.25 8.88 2,941 1582 5.47
* C clang #4 13.38 13.39 2,351 1190 5.22
* Rust #6 3.81 15.06 3,985 1260 11.92
Rust #4 6.94 27.12 3,985 1026 11.71
Rust #5 7.41 28.89 3,990 1023 11.79
C clang #5 8.13 32.00—32.15 4,764 917 5.37
C clang #3 34.18 34.19—34.26 2,355 574 5.02
* C clang #2 8.70 34.15—34.33 2,945 1563 5.27
Rust #2 9.19 36.04—36.08 3,723 1198 11.14
C clang #8 36.36 36.44—36.51 2,347 483 5.13
C clang 36.52 36.54—36.63 2,347 514 5.35
n-body      
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
* Rust #9 2.19 1.90—3.09 3,023 1881 11.01
* C clang #9 2.20 2.20 2,417 1639 6.15
* Rust #7 3.24 3.24 2,937 1759 10.53
Rust #3 3.46 3.46 2,937 1774 10.62
Rust #2 3.65 3.65 3,031 1809 10.49
* Rust #6 4.37 4.36—4.49 3,031 1796 10.86
* C clang #5 4.86 4.86 2,470 1436 5.17
* Rust #5 5.02 5.03 3,035 2224 10.61
Rust #4 5.13 4.99—5.53 3,039 1810 10.50
C clang #6 5.17 5.17 2,970 1186 5.42
C clang 5.38 5.39 2,978 1179 5.06
C clang #2 5.43 5.43 2,966 1270 5.25
Rust 5.52 5.50—5.60 3,027 1483 10.84
* C clang #4 5.60 5.61 2,953 1398 6.30
C clang #8 5.70 5.56—6.19 2,961 1195 5.27
C clang #3 6.13 6.13 2,966 1214 5.26
C clang #7 6.78 6.80 2,966 1250 5.05
spectral-norm      
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
* C clang #6 0.39 1.55 4,686 1203 6.45
* Rust #6 0.72 2.85 3,981 1132 12.60
Rust #4 0.72 2.85 4,047 823 12.00
* Rust #5 0.72 2.86 4,018 1062 11.30
* C clang #4 0.73 2.87 5,382 1145 5.66
* C clang #5 0.73 2.87—2.91 5,403 576 5.55
* Rust #2 0.72 2.86 4,145 1117 11.00
* Rust 0.72 2.86 4,104 1262 11.75
* C clang #2 0.74 4.30—7.09 5,288 941 6.43
* Rust #3 0.74 2.94 4,121 1060 10.92
C clang #8 5.41 5.42 3,211 389 5.15
C clang #3 1.45 5.75—5.79 5,423 470 5.58
* C clang #7 1.84 8.98—10.12 5,439 906 6.66
* Rust #7   Empty  
mandelbrot      
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
* Rust #4 0.95 3.78 35,598 1301 12.26
* Rust #6 1.08 4.21 36,426 1338 12.65
Rust #7 1.10 4.34 35,906 763 12.32
Rust #2 1.10 4.36—4.52 35,754 770 12.80
Rust #5 1.12 4.38 36,311 725 12.27
Rust #3 1.15 4.57 14,615 1013 12.66
C clang #9 1.24 4.92 36,811 700 5.32
C clang #5 1.54 6.10 37,044 788 5.35
Rust 2.01 7.90 42,631 874 10.94
* C clang #4 3.49 13.89—13.95 36,102 805 5.26
* C clang 3.51 13.95 35,643 828 5.65
* C clang #7 3.54 14.02—14.06 36,491 1000 5.49
* C clang #3 3.56 14.16—14.20 35,418 769 5.06
C clang #8 25.51 25.52 2,359 412 5.22
* C clang #6   Empty  
fasta      
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
C clang #3 0.79 0.79 2,273 1469 4.57
C clang #5 1.20 1.20 2,204 1286 5.64
* Rust #7 0.78 1.55 4,772 2533 11.68
Rust #3 2.03 2.03 3,199 1235 10.95
C clang #2 2.44 2.44 2,163 1299 5.14
C clang #6 1.04 3.05 5,272 1936 5.40
Rust #9 0.94 3.20—3.33 5,534 1952 11.24
C clang #7 0.83 3.28—3.32 5,861 2276 5.29
Rust #2 0.95 3.46—3.50 5,554 1910 11.45
C clang 3.47 3.47 2,392 1213 5.28
Rust #5 0.94 3.48—3.53 5,554 1963 12.19
Rust #4 3.52 3.53 128,217 944 10.63
Rust #6 3.53 3.53 128,381 959 10.62
Rust 4.45 4.54—4.61 3,113 1240 11.09
C clang #8 8.08 8.14—8.25 2,200 839 5.08
C clang #4   Empty  
k-nucleotide      
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
Rust #7 2.57 8.13—8.39 139,088 1585 13.43
Rust #3 3.28 9.72—10.13 142,631 1549 11.91
Rust #6 2.79 10.06—10.15 165,048 1697 14.10
Rust #5 3.88 11.66—11.92 143,155 1745 12.40
C clang 6.27 13.93—14.23 134,038 1512 6.01
Rust #2 6.00 15.71—16.24 142,946 1350 11.85
Rust #9 6.33 17.72—18.82 141,099 1850 14.41
Rust #4 6.69 18.00—18.74 142,090 1755 13.13
Rust 21.08 64.42—65.12 161,219 1086 12.16
reverse-complement      
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
* C clang #7 0.45 0.61—0.67 514,220 1899 6.22
C clang #9 0.47 0.72 514,216 1551 5.13
* Rust 0.55 0.85 512,963 2762 11.72
Rust #2 1.01 1.61 1,022,128 1332 11.04
C clang #2 1.17 1.70 1,021,891 757 5.17
Rust #3 1.02 1.72 1,022,034 1105 11.45
C clang #5 1.97 2.03—2.09 1,020,813 654 5.16
* C clang #4 3.77 3.78 514,023 716 4.93
C clang #6 1.05 4.15—4.20 714,764 828 5.90
binary-trees      [ Contentious. Different approaches. ]
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
Rust #5 1.07 3.84—4.01 139,121 771 1.28
Rust #2 1.17 4.16—4.25 140,157 729 12.50
Rust #4 1.38 4.98—5.02 202,686 765 12.32
Rust #3 1.40 5.15—5.26 172,392 762 11.90
C clang #2 1.66 5.23—6.05 176,116 816 5.77
C clang #3 1.91 5.90 138,719 842 5.90
Rust 2.10 7.44 137,417 760 11.36
C clang 17.72 17.78—18.29 271,938 660 5.20
C clang #5 9.25 33.42—33.59 361,689 914 4.96
pidigits      [ Contentious. Different libraries. ]
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
Rust #4 0.71 0.72 4,055 804 11.82
C clang #2 0.74 0.74 3,990 422 5.19
* Rust #2 0.75 0.75 4,387 1312 10.44
* Rust 0.75 0.75 4,243 1426 10.19
C clang 0.75 0.75 3,731 459 5.35
* Rust #3 0.75 0.75 4,510 1373 10.10
regex-redux      [ Contentious. Different libraries. ]
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
Rust #6 1.21 1.46 159,846 994 13.12
Rust #5 1.35 1.58 209,863 777 12.67
Rust 1.35 1.59—1.63 159,793 811 12.22
Rust #3 1.38 1.63 210,379 726 13.51
Rust #4 1.38 1.64 206,811 771 12.41
Rust #2 1.38 1.64 159,937 707 11.67
* Rust #7 0.78 2.00 157,442 2464 12.48
C clang #5 0.83 2.82 159,736 1403 5.40
C clang #2 3.22 3.22 106,783 1121 5.07
C clang #4 0.99 3.82—3.86 159,539 1237 5.11
C clang #3 1.76 4.34 109,867 1273 5.08
Rust

1.84.1
(e71f9a9a9
2025-01-27)
LLVM version: 19.1.5

C clang

Ubuntu clang version 18.1.8 (11)