The Computer Language
25.02 Benchmarks Game

C gcc 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 gcc #6 2.14 8.44 2,712 1582 2.68
* 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
* C gcc #4 14.05 14.06 2,351 1190 2.31
C gcc #5 7.28 28.32—28.45 2,949 917 2.17
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
C gcc #3 36.84 36.84—36.89 2,343 574 2.19
C++ g++ #3 37.89 37.90—37.99 2,351 600 2.70
C gcc #8 39.34 39.52—40.22 2,343 483 2.20
C gcc 39.65 39.64—40.07 2,343 514 2.12
* C gcc #2 10.18 39.98—40.15 2,695 1563 2.51
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 gcc #9 2.10 2.10 2,482 1639 2.99
* C++ g++ #0 2.15 2.16 2,417 1933 3.66
* C gcc #4 4.06 4.06 2,499 1398 2.98
* C++ g++ #7 4.09 4.12—4.17 5,124 1815 4.18
C gcc #6 4.98 4.99 2,482 1186 2.33
C++ g++ #9 5.15 5.17 2,486 1536 3.03
C gcc #2 5.20 5.20 2,490 1270 2.43
C gcc 5.23 5.23 2,486 1179 2.58
C gcc #3 5.24 5.24 2,482 1214 2.42
C++ g++ #3 5.33 5.34 2,482 1402 2.85
* C gcc #5 5.44 5.44 2,494 1436 2.31
* C++ g++ #4 5.46 5.46 2,482 1434 2.83
C gcc #8 5.54 5.54 2,486 1195 2.52
* 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 gcc #7 6.89 6.90 2,490 1250 2.32
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
* C gcc #6 0.40 1.60 3,199 1203 3.38
* C gcc #5 0.72 2.86 3,858 576 2.52
* C gcc #7 0.72 2.86 4,067 906 3.21
* C gcc #4 0.72 2.86 3,719 1145 2.49
* C++ g++ #6 0.72 2.86 3,981 1050 3.08
* C++ g++ #5 1.33 5.28 5,820 1050 2.86
C++ g++ 5.34 5.34 5,292 459 3.75
C gcc #8 5.41 5.41 3,219 389 2.42
C gcc #3 1.43 5.71 4,080 470 2.42
C++ g++ #7 1.53 6.07 4,071 1284 2.71
* C gcc #2   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
* C++ g++ #6 0.98 3.87 37,908 1014 4.36
* C gcc #6 1.29 5.11 35,578 1147 2.64
C gcc #5 1.64 6.32 35,582 788 2.38
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 gcc #4 3.50 13.91 35,197 805 2.16
* C gcc #7 3.51 13.94 35,447 1000 2.60
* C gcc 3.50 13.94 35,017 828 2.23
* C gcc #3 3.55 14.12 34,873 769 2.26
C gcc #9 4.07 15.72 35,394 700 2.47
C++ g++ #2 16.96 16.96 36,704 700 3.28
C gcc #8 25.17 25.18 2,355 412 2.29
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
C gcc #3 0.79 0.79 2,236 1469 2.26
C gcc #5 1.24 1.25 2,154 1286 2.42
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
C++ g++ #3 2.63 2.63 5,284 1311 3.33
C gcc #2 2.77 2.77 2,204 1299 2.25
C gcc #6 0.95 2.77—2.81 3,748 1936 2.44
C++ g++ #7 0.88 3.06 6,304 2711 4.58
C gcc #7 0.83 3.28 4,514 2276 2.39
C++ g++ #4 3.34 3.34 2,363 1291 3.03
C++ g++ #5 1.07 3.69—3.73 7,012 2345 3.90
C gcc 3.71 3.71 2,421 1213 2.25
C++ g++ #6 1.08 3.90 7,127 2326 3.72
C gcc #8 8.27 8.31—8.37 2,195 839 2.20
C gcc #4   Empty  
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
C gcc 3.58 12.06—12.40 135,234 1512 2.82
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
reverse-complement      
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
* C gcc #7 0.44 0.62 514,208 1899 3.13
* C++ g++ #2 0.76 0.76 514,101 2099 4.30
C gcc #9 0.49 0.78 514,159 1551 2.20
C gcc #6 0.97 1.37 693,969 828 2.26
C gcc #5 1.54 1.54 1,020,662 654 2.05
C gcc #2 1.07 1.59 1,021,755 757 2.15
* C gcc #4 3.70 3.71 514,077 716 2.22
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
C++ g++ #5 1.17 4.12—4.17 208,171 891 3.87
C gcc #2 1.56 4.30—4.45 174,780 816 3.21
C++ g++ #9 1.76 4.66—4.82 140,571 815 4.05
C gcc #3 1.96 4.79—4.93 138,711 842 2.94
C++ g++ #6 1.93 4.90—5.09 273,973 851 4.98
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
C++ g++ 2.69 9.43—9.52 1,896,727 760 5.34
C gcc 21.21 21.39—21.70 272,065 660 2.37
C++ g++ #2 22.77 22.81—23.05 274,080 514 3.52
C gcc #5 8.71 31.85—32.27 361,587 914 2.34
pidigits      [ Contentious. Different libraries. ]
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
C++ g++ #4 0.72 0.72 6,496 521 3.45
* C++ g++ #5 0.73 0.73 6,300 804 3.34
C gcc #2 0.74 0.74 4,006 422 2.25
C gcc 0.75 0.75 3,727 459 2.30
regex-redux      [ Contentious. Different libraries. ]
  elapsed Mean or 95% CI      
source secs cpu secs mem gz make
C gcc #5 0.81 2.05 157,463 1403 2.47
C++ g++ #6 1.14 2.25 285,639 2856 5.06
C gcc #2 3.22 3.22 106,713 1121 2.14
C gcc #4 0.97 3.30 157,417 1237 2.18
C gcc #3 1.73 3.32 107,401 1273 2.27
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  
C gcc

gcc (Ubuntu 14.2.0-4ubuntu2) 14.2.0

C++ g++

g++ (Ubuntu 14.2.0-4ubuntu2) 14.2.0