The Computer Language
25.03 Benchmarks Game

Rust versus C++ g++

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++ g++ #6 3.33 13.12 5,800 1535 4.64
* C++ g++ #7 14.06 14.04—14.11 2,449 1156 2.95
* 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++ g++ #5 7.86 30.73—30.82 5,792 987 3.67
C++ g++ #4 8.91 34.99—35.47 5,710 1445 12.14
C++ g++ #2 9.14 35.88—36.26 5,698 1446 11.86
Rust #2 9.19 36.04—36.08 3,723 1198 11.14
C++ g++ #3 37.89 37.90—37.99 2,351 600 2.70
C++ g++ 10.53 41.25—41.55 5,534 1065 3.88
n-body      
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
* C++ g++ #0 2.15 2.16 2,417 1933 3.66
* Rust #9 2.19 1.90—3.09 3,023 1881 11.01
* 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
* C++ g++ #7 4.09 4.12—4.17 5,124 1815 4.18
Rust #6 4.37 4.36—4.49 3,031 1796 10.86
* 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++ g++ #9 5.15 5.17 2,486 1536 3.03
C++ g++ #3 5.33 5.34 2,482 1402 2.85
* C++ g++ #4 5.46 5.46 2,482 1434 2.83
Rust 5.52 5.50—5.60 3,027 1483 10.84
C++ g++ #2 6.02 6.02—6.10 2,490 1524 3.04
C++ g++ #5 6.33 6.35 2,478 1544 2.92
C++ g++ 6.62 6.64 2,499 1666 3.15
C++ g++ #6 6.94 6.93—6.98 2,499 1674 2.98
spectral-norm      
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
* 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
* Rust #2 0.72 2.86 4,145 1117 11.00
* Rust 0.72 2.86 4,104 1262 11.75
* C++ g++ #6 0.72 2.86 3,981 1050 3.08
* Rust #3 0.74 2.94 4,121 1060 10.92
* C++ g++ #5 1.33 5.28 5,820 1050 2.86
C++ g++ 5.34 5.34 5,292 459 3.75
C++ g++ #7 1.53 6.07 4,071 1284 2.71
Rust #7   Empty  
mandelbrot      
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
* C++ g++ #4 0.89 3.46 37,941 3554 5.04
* C++ g++ 0.90 3.48 37,626 1797 3.59
Rust #4 0.95 3.78 35,598 1301 12.26
* C++ g++ #6 0.98 3.87 37,908 1014 4.36
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
Rust 2.01 7.90 42,631 874 10.94
C++ g++ #0 2.36 9.31 38,281 2752 4.60
C++ g++ #7 4.87 13.30 38,048 749 3.03
C++ g++ #5 13.47 13.49 36,884 596 2.76
C++ g++ #9 3.53 13.59 37,863 732 3.03
C++ g++ #2 16.96 16.96 36,704 700 3.28
C++ g++ #3 27.38 27.38 5,181 421 3.69
fasta      
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
* Rust #7 0.78 1.55 4,772 2533 11.68
* C++ g++ #9 0.78 1.56 6,214 2758 6.43
C++ g++ #2 1.85 1.85 5,108 1129 2.89
C++ g++ 1.93 1.93 5,104 1064 2.98
Rust #3 2.03 2.03 3,199 1235 10.95
C++ g++ #3 2.63 2.63 5,284 1311 3.33
C++ g++ #7 0.88 3.06 6,304 2711 4.58
Rust #9 0.94 3.20—3.33 5,534 1952 11.24
C++ g++ #4 3.34 3.34 2,363 1291 3.03
Rust #2 0.95 3.46—3.50 5,554 1910 11.45
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
C++ g++ #5 1.07 3.69—3.73 7,012 2345 3.90
C++ g++ #6 1.08 3.90 7,127 2326 3.72
Rust 4.45 4.54—4.61 3,113 1240 11.09
k-nucleotide      
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
C++ g++ #2 2.02 6.05—6.54 162,349 1634 7.41
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++ g++ #3 4.19 13.83—14.44 171,622 1280 5.17
C++ g++ 7.04 15.17—15.69 778,510 1452 6.55
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++ g++ #2 0.76 0.76 514,101 2099 4.30
* Rust 0.55 0.85 512,963 2762 11.72
Rust #2 1.01 1.61 1,022,128 1332 11.04
Rust #3 1.02 1.72 1,022,034 1105 11.45
C++ g++ 6.55 6.55—6.68 1,006,805 599 3.43
C++ g++ #5 37.66 37.65—37.69 792,846 704 3.40
C++ g++ #6   Bad Output  
C++ g++ #3   Bad Output  
binary-trees      [ Contentious. Different approaches. ]
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
C++ g++ #7 1.01 3.46—3.62 175,108 896 7.50
Rust #5 1.07 3.84—4.01 139,121 771 1.28
C++ g++ #5 1.17 4.12—4.17 208,171 891 3.87
Rust #2 1.17 4.16—4.25 140,157 729 12.50
C++ g++ #9 1.76 4.66—4.82 140,571 815 4.05
C++ g++ #6 1.93 4.90—5.09 273,973 851 4.98
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++ g++ #3 2.28 5.06—5.10 273,715 951 4.79
C++ g++ #4 2.22 5.20—5.33 273,977 826 5.16
Rust 2.10 7.44 137,417 760 11.36
C++ g++ 2.69 9.43—9.52 1,896,727 760 5.34
C++ g++ #2 22.77 22.81—23.05 274,080 514 3.52
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++ g++ #4 0.72 0.72 6,496 521 3.45
* C++ g++ #5 0.73 0.73 6,300 804 3.34
* Rust #2 0.75 0.75 4,387 1312 10.44
* Rust 0.75 0.75 4,243 1426 10.19
* 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++ g++ #6 1.14 2.25 285,639 2856 5.06
C++ g++ #3 12.37 18.03—18.68 222,614 859 12.29
C++ g++   Empty  
C++ g++ #2   Empty  
C++ g++ #5   Empty  
C++ g++ #4   Empty  
Rust

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

C++ g++

g++ (Ubuntu 14.2.0-4ubuntu2) 14.2.0