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mordantemordante
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[libc++][format][4/7] Improves std::format_to performance.
This changes the __output_buffer users for format_to to the new structure. It also uses the new allocating buffer to improve performance. write_double_comparison: Before ---------------------------------------------------------------------------------------- Benchmark Time CPU Iterations ---------------------------------------------------------------------------------------- BM_sprintf 197 ns 197 ns 3537000 BM_to_string 219 ns 219 ns 3200000 BM_to_chars 42.3 ns 42.3 ns 16490000 BM_to_chars_as_string 48.1 ns 48.1 ns 14508000 BM_format 167 ns 167 ns 4207000 BM_format_to_back_inserter<std::string> 179 ns 179 ns 3914000 BM_format_to_back_inserter<std::vector<char>> 216 ns 216 ns 3234000 BM_format_to_back_inserter<std::list<char>> 752 ns 752 ns 932000 BM_format_to_iterator/<std::array> 165 ns 165 ns 4257000 BM_format_to_iterator/<std::string> 165 ns 165 ns 4251000 BM_format_to_iterator/<std::vector> 165 ns 165 ns 4254000 After ---------------------------------------------------------------------------------------- Benchmark Time CPU Iterations ---------------------------------------------------------------------------------------- BM_sprintf 197 ns 197 ns 3548000 BM_to_string 219 ns 219 ns 3203000 BM_to_chars 42.3 ns 42.3 ns 16540000 BM_to_chars_as_string 48.2 ns 48.2 ns 14532000 BM_format 167 ns 167 ns 4190000 BM_format_to_back_inserter<std::string> 176 ns 176 ns 3959000 BM_format_to_back_inserter<std::vector<char>> 211 ns 211 ns 3312000 BM_format_to_back_inserter<std::list<char>> 752 ns 752 ns 934000 BM_format_to_iterator/<std::array> 162 ns 162 ns 4313000 BM_format_to_iterator/<std::string> 162 ns 162 ns 4307000 BM_format_to_iterator/<std::vector> 162 ns 162 ns 4308000 Comparison Benchmark Time CPU Time Old Time New CPU Old CPU New -------------------------------------------------------------------------------------------------------------------------------------------- BM_sprintf +0.0003 +0.0002 197 197 197 197 BM_to_string -0.0004 -0.0004 219 219 219 219 BM_to_chars +0.0003 +0.0003 42 42 42 42 BM_to_chars_as_string +0.0004 +0.0004 48 48 48 48 BM_format +0.0016 +0.0016 167 167 167 167 BM_format_to_back_inserter<std::string> -0.0128 -0.0127 179 176 179 176 BM_format_to_back_inserter<std::vector<char>> -0.0216 -0.0216 216 211 216 211 BM_format_to_back_inserter<std::list<char>> -0.0008 -0.0008 752 752 752 752 BM_format_to_iterator/<std::array> -0.0137 -0.0137 165 162 165 162 BM_format_to_iterator/<std::string> -0.0154 -0.0153 165 162 165 162 BM_format_to_iterator/<std::vector> -0.0138 -0.0138 165 162 165 162 OVERALL_GEOMEAN -0.0069 -0.0069 0 0 0 0 write_int_comparison: Before ---------------------------------------------------------------------------------------- Benchmark Time CPU Iterations ---------------------------------------------------------------------------------------- BM_sprintf 80.3 ns 80.1 ns 8703000 BM_to_string 15.0 ns 14.9 ns 46849000 BM_to_chars 4.94 ns 4.92 ns 139052000 BM_to_chars_as_string 15.6 ns 15.6 ns 44945000 BM_format 62.1 ns 61.9 ns 11302000 BM_format_to_back_inserter<std::string> 70.3 ns 70.1 ns 9984000 BM_format_to_back_inserter<std::vector<char>> 92.9 ns 92.7 ns 7520000 BM_format_to_back_inserter<std::list<char>> 239 ns 239 ns 2926000 BM_format_to_iterator/<std::array> 60.6 ns 60.4 ns 11582000 BM_format_to_iterator/<std::string> 60.2 ns 60.0 ns 11671000 BM_format_to_iterator/<std::vector> 60.1 ns 60.0 ns 11691000 After ---------------------------------------------------------------------------------------- Benchmark Time CPU Iterations ---------------------------------------------------------------------------------------- BM_sprintf 81.3 ns 81.2 ns 8546000 BM_to_string 14.9 ns 14.9 ns 46809000 BM_to_chars 4.93 ns 4.93 ns 138278000 BM_to_chars_as_string 15.4 ns 15.4 ns 45504000 BM_format 62.0 ns 61.9 ns 11330000 BM_format_to_back_inserter<std::string> 69.0 ns 68.9 ns 10164000 BM_format_to_back_inserter<std::vector<char>> 90.4 ns 90.3 ns 7736000 BM_format_to_back_inserter<std::list<char>> 242 ns 242 ns 2891000 BM_format_to_iterator/<std::array> 58.6 ns 58.6 ns 11952000 BM_format_to_iterator/<std::string> 58.2 ns 58.1 ns 12052000 BM_format_to_iterator/<std::vector> 58.4 ns 58.3 ns 11983000 Comparison Benchmark Time CPU Time Old Time New CPU Old CPU New -------------------------------------------------------------------------------------------------------------------------------------------- BM_sprintf +0.0116 +0.0132 80 81 80 81 BM_to_string -0.0050 -0.0036 15 15 15 15 BM_to_chars -0.0005 +0.0010 5 5 5 5 BM_to_chars_as_string -0.0168 -0.0149 16 15 16 15 BM_format -0.0015 +0.0001 62 62 62 62 BM_format_to_back_inserter<std::string> -0.0186 -0.0172 70 69 70 69 BM_format_to_back_inserter<std::vector<char>> -0.0271 -0.0256 93 90 93 90 BM_format_to_back_inserter<std::list<char>> +0.0104 +0.0119 239 242 239 242 BM_format_to_iterator/<std::array> -0.0322 -0.0304 61 59 60 59 BM_format_to_iterator/<std::string> -0.0330 -0.0317 60 58 60 58 BM_format_to_iterator/<std::vector> -0.0285 -0.0270 60 58 60 58 OVERALL_GEOMEAN -0.0130 -0.0114 0 0 0 0 write_string_comparison: Before --------------------------------------------------------------------------------------------------------------- Benchmark Time CPU Iterations --------------------------------------------------------------------------------------------------------------- BM_sprintf/C string len = 6 3.58 ns 3.58 ns 195215226 BM_format/C string len = 6 49.6 ns 49.6 ns 14114169 BM_format_to_back_inserter<std::string>/C string len = 6 56.8 ns 56.7 ns 12354503 BM_format_to_back_inserter<std::vector<char>>/C string len = 6 73.0 ns 72.9 ns 9558050 BM_format_to_back_inserter<std::deque<char>>/C string len = 6 156 ns 156 ns 4498803 BM_format_to_back_inserter<std::list<char>>/C string len = 6 136 ns 136 ns 5164775 BM_format_to_iterator/<std::array> C string len = 6 46.6 ns 46.5 ns 15056991 BM_format_to_iterator/<std::string> C string len = 6 47.2 ns 47.1 ns 14865806 BM_format_to_iterator/<std::vector> C string len = 6 46.4 ns 46.4 ns 15115383 BM_format_to_iterator/<std::deque> C string len = 6 52.5 ns 52.4 ns 13340197 BM_format/string len = 6 49.7 ns 49.6 ns 14109221 BM_format_to_back_inserter<std::string>/string len = 6 55.7 ns 55.6 ns 12566789 BM_format_to_back_inserter<std::vector<char>>/string len = 6 73.0 ns 72.9 ns 9615078 BM_format_to_back_inserter<std::deque<char>>/string len = 6 155 ns 154 ns 4527026 BM_format_to_back_inserter<std::list<char>>/string len = 6 133 ns 133 ns 5260984 BM_format_to_iterator/<std::array> string len = 6 46.7 ns 46.7 ns 14997233 BM_format_to_iterator/<std::string> string len = 6 47.3 ns 47.3 ns 14823572 BM_format_to_iterator/<std::vector> string len = 6 46.4 ns 46.4 ns 15096193 BM_format_to_iterator/<std::deque> string len = 6 52.8 ns 52.8 ns 13255170 BM_format/string_view len = 6 48.9 ns 48.9 ns 14343000 BM_format_to_back_inserter<std::string>/string_view len = 6 56.2 ns 56.2 ns 12465511 BM_format_to_back_inserter<std::vector<char>>/string_view len = 6 72.0 ns 72.0 ns 9713443 BM_format_to_back_inserter<std::deque<char>>/string_view len = 6 153 ns 153 ns 4567407 BM_format_to_back_inserter<std::list<char>>/string_view len = 6 132 ns 132 ns 5299318 BM_format_to_iterator/<std::array> string_view len = 6 46.3 ns 46.3 ns 15136404 BM_format_to_iterator/<std::string> string_view len = 6 46.3 ns 46.2 ns 15109243 BM_format_to_iterator/<std::vector> string_view len = 6 46.2 ns 46.2 ns 15109163 BM_format_to_iterator/<std::deque> string_view len = 6 51.7 ns 51.6 ns 13596607 BM_sprintf/C string len = 60 4.84 ns 4.84 ns 144840145 BM_format/C string len = 60 63.7 ns 63.6 ns 10992968 BM_format_to_back_inserter<std::string>/C string len = 60 75.1 ns 75.0 ns 9344335 BM_format_to_back_inserter<std::vector<char>>/C string len = 60 88.7 ns 88.6 ns 7890501 BM_format_to_back_inserter<std::deque<char>>/C string len = 60 285 ns 285 ns 2456362 BM_format_to_back_inserter<std::list<char>>/C string len = 60 1164 ns 1163 ns 601922 BM_format_to_iterator/<std::array> C string len = 60 46.3 ns 46.3 ns 15130688 BM_format_to_iterator/<std::string> C string len = 60 47.0 ns 47.0 ns 14932772 BM_format_to_iterator/<std::vector> C string len = 60 46.4 ns 46.3 ns 15105615 BM_format_to_iterator/<std::deque> C string len = 60 52.1 ns 52.1 ns 13457398 BM_format/string len = 60 62.2 ns 62.2 ns 11214844 BM_format_to_back_inserter<std::string>/string len = 60 74.7 ns 74.7 ns 9362502 BM_format_to_back_inserter<std::vector<char>>/string len = 60 86.6 ns 86.5 ns 8089613 BM_format_to_back_inserter<std::deque<char>>/string len = 60 279 ns 279 ns 2512066 BM_format_to_back_inserter<std::list<char>>/string len = 60 1167 ns 1165 ns 599277 BM_format_to_iterator/<std::array> string len = 60 46.7 ns 46.7 ns 15001681 BM_format_to_iterator/<std::string> string len = 60 47.3 ns 47.2 ns 14812974 BM_format_to_iterator/<std::vector> string len = 60 46.4 ns 46.4 ns 15082006 BM_format_to_iterator/<std::deque> string len = 60 52.3 ns 52.2 ns 13388503 BM_format/string_view len = 60 62.1 ns 62.0 ns 11284789 BM_format_to_back_inserter<std::string>/string_view len = 60 74.4 ns 74.3 ns 9417398 BM_format_to_back_inserter<std::vector<char>>/string_view len = 60 86.4 ns 86.3 ns 8130553 BM_format_to_back_inserter<std::deque<char>>/string_view len = 60 279 ns 279 ns 2504047 BM_format_to_back_inserter<std::list<char>>/string_view len = 60 1164 ns 1163 ns 602294 BM_format_to_iterator/<std::array> string_view len = 60 46.7 ns 46.6 ns 15000596 BM_format_to_iterator/<std::string> string_view len = 60 46.4 ns 46.4 ns 15109351 BM_format_to_iterator/<std::vector> string_view len = 60 46.4 ns 46.4 ns 15094222 BM_format_to_iterator/<std::deque> string_view len = 60 52.1 ns 52.1 ns 13453584 BM_sprintf/C string len = 6000 77.1 ns 77.0 ns 9095120 BM_format/C string len = 6000 345 ns 345 ns 2032789 BM_format_to_back_inserter<std::string>/C string len = 6000 1001 ns 1000 ns 697688 BM_format_to_back_inserter<std::vector<char>>/C string len = 6000 972 ns 971 ns 720843 BM_format_to_back_inserter<std::deque<char>>/C string len = 6000 15129 ns 15114 ns 46330 BM_format_to_back_inserter<std::list<char>>/C string len = 6000 115290 ns 115167 ns 6065 BM_format_to_iterator/<std::array> C string len = 6000 161 ns 161 ns 4358261 BM_format_to_iterator/<std::string> C string len = 6000 154 ns 154 ns 4559197 BM_format_to_iterator/<std::vector> C string len = 6000 150 ns 150 ns 4660257 BM_format_to_iterator/<std::deque> C string len = 6000 463 ns 463 ns 1512400 BM_format/string len = 6000 282 ns 281 ns 2494935 BM_format_to_back_inserter<std::string>/string len = 6000 941 ns 940 ns 742779 BM_format_to_back_inserter<std::vector<char>>/string len = 6000 933 ns 932 ns 749515 BM_format_to_back_inserter<std::deque<char>>/string len = 6000 15110 ns 15095 ns 46447 BM_format_to_back_inserter<std::list<char>>/string len = 6000 115131 ns 114854 ns 6080 BM_format_to_iterator/<std::array> string len = 6000 119 ns 118 ns 5903779 BM_format_to_iterator/<std::string> string len = 6000 108 ns 107 ns 6528813 BM_format_to_iterator/<std::vector> string len = 6000 107 ns 107 ns 6574916 BM_format_to_iterator/<std::deque> string len = 6000 395 ns 394 ns 1776801 BM_format/string_view len = 6000 282 ns 281 ns 2484729 BM_format_to_back_inserter<std::string>/string_view len = 6000 936 ns 934 ns 751176 BM_format_to_back_inserter<std::vector<char>>/string_view len = 6000 925 ns 922 ns 759237 BM_format_to_back_inserter<std::deque<char>>/string_view len = 6000 15072 ns 15036 ns 46625 BM_format_to_back_inserter<std::list<char>>/string_view len = 6000 115332 ns 115059 ns 6094 BM_format_to_iterator/<std::array> string_view len = 6000 119 ns 119 ns 5907620 BM_format_to_iterator/<std::string> string_view len = 6000 108 ns 107 ns 6509157 BM_format_to_iterator/<std::vector> string_view len = 6000 107 ns 107 ns 6556001 BM_format_to_iterator/<std::deque> string_view len = 6000 392 ns 391 ns 1791454 After --------------------------------------------------------------------------------------------------------------- Benchmark Time CPU Iterations --------------------------------------------------------------------------------------------------------------- BM_sprintf/C string len = 6 3.57 ns 3.56 ns 196180052 BM_format/C string len = 6 49.5 ns 49.4 ns 14164054 BM_format_to_back_inserter<std::string>/C string len = 6 56.0 ns 55.9 ns 12538707 BM_format_to_back_inserter<std::vector<char>>/C string len = 6 75.9 ns 75.7 ns 9240871 BM_format_to_back_inserter<std::deque<char>>/C string len = 6 158 ns 157 ns 4451418 BM_format_to_back_inserter<std::list<char>>/C string len = 6 140 ns 140 ns 5027890 BM_format_to_iterator/<std::array> C string len = 6 45.8 ns 45.7 ns 15319048 BM_format_to_iterator/<std::string> C string len = 6 45.6 ns 45.5 ns 15401554 BM_format_to_iterator/<std::vector> C string len = 6 45.8 ns 45.7 ns 15300166 BM_format_to_iterator/<std::deque> C string len = 6 52.7 ns 52.6 ns 13285185 BM_format/string len = 6 48.8 ns 48.7 ns 14348744 BM_format_to_back_inserter<std::string>/string len = 6 55.2 ns 55.0 ns 12741162 BM_format_to_back_inserter<std::vector<char>>/string len = 6 74.1 ns 73.9 ns 9486802 BM_format_to_back_inserter<std::deque<char>>/string len = 6 161 ns 160 ns 4378461 BM_format_to_back_inserter<std::list<char>>/string len = 6 138 ns 138 ns 5093901 BM_format_to_iterator/<std::array> string len = 6 46.2 ns 46.1 ns 15206070 BM_format_to_iterator/<std::string> string len = 6 45.9 ns 45.8 ns 15308600 BM_format_to_iterator/<std::vector> string len = 6 46.0 ns 45.7 ns 15294308 BM_format_to_iterator/<std::deque> string len = 6 52.6 ns 52.5 ns 13337923 BM_format/string_view len = 6 48.0 ns 47.9 ns 14613157 BM_format_to_back_inserter<std::string>/string_view len = 6 54.6 ns 54.5 ns 12873822 BM_format_to_back_inserter<std::vector<char>>/string_view len = 6 75.0 ns 74.8 ns 9336395 BM_format_to_back_inserter<std::deque<char>>/string_view len = 6 157 ns 156 ns 4485483 BM_format_to_back_inserter<std::list<char>>/string_view len = 6 137 ns 137 ns 5103661 BM_format_to_iterator/<std::array> string_view len = 6 45.2 ns 45.1 ns 15521006 BM_format_to_iterator/<std::string> string_view len = 6 44.6 ns 44.5 ns 15774831 BM_format_to_iterator/<std::vector> string_view len = 6 44.8 ns 44.7 ns 15675865 BM_format_to_iterator/<std::deque> string_view len = 6 52.2 ns 52.0 ns 13439531 BM_sprintf/C string len = 60 4.84 ns 4.83 ns 145140791 BM_format/C string len = 60 65.3 ns 65.1 ns 10780458 BM_format_to_back_inserter<std::string>/C string len = 60 74.9 ns 74.7 ns 9347593 BM_format_to_back_inserter<std::vector<char>>/C string len = 60 90.8 ns 90.7 ns 7662645 BM_format_to_back_inserter<std::deque<char>>/C string len = 60 294 ns 294 ns 2381522 BM_format_to_back_inserter<std::list<char>>/C string len = 60 1212 ns 1212 ns 577916 BM_format_to_iterator/<std::array> C string len = 60 45.6 ns 45.6 ns 15344329 BM_format_to_iterator/<std::string> C string len = 60 45.3 ns 45.3 ns 15441949 BM_format_to_iterator/<std::vector> C string len = 60 45.6 ns 45.6 ns 15338324 BM_format_to_iterator/<std::deque> C string len = 60 52.3 ns 52.3 ns 13400650 BM_format/string len = 60 63.9 ns 63.9 ns 10949816 BM_format_to_back_inserter<std::string>/string len = 60 74.5 ns 74.5 ns 9381269 BM_format_to_back_inserter<std::vector<char>>/string len = 60 88.1 ns 88.1 ns 7951042 BM_format_to_back_inserter<std::deque<char>>/string len = 60 295 ns 295 ns 2376712 BM_format_to_back_inserter<std::list<char>>/string len = 60 1212 ns 1212 ns 577933 BM_format_to_iterator/<std::array> string len = 60 46.3 ns 46.3 ns 15126961 BM_format_to_iterator/<std::string> string len = 60 46.0 ns 46.0 ns 15209386 BM_format_to_iterator/<std::vector> string len = 60 46.0 ns 46.0 ns 15215256 BM_format_to_iterator/<std::deque> string len = 60 53.6 ns 53.6 ns 13026167 BM_format/string_view len = 60 61.6 ns 61.6 ns 11367134 BM_format_to_back_inserter<std::string>/string_view len = 60 74.4 ns 74.4 ns 9414535 BM_format_to_back_inserter<std::vector<char>>/string_view len = 60 87.6 ns 87.6 ns 7985409 BM_format_to_back_inserter<std::deque<char>>/string_view len = 60 291 ns 291 ns 2409202 BM_format_to_back_inserter<std::list<char>>/string_view len = 60 1205 ns 1205 ns 580314 BM_format_to_iterator/<std::array> string_view len = 60 45.2 ns 45.2 ns 15495462 BM_format_to_iterator/<std::string> string_view len = 60 44.9 ns 45.0 ns 15592145 BM_format_to_iterator/<std::vector> string_view len = 60 44.9 ns 44.9 ns 15573834 BM_format_to_iterator/<std::deque> string_view len = 60 52.3 ns 52.3 ns 13381282 BM_sprintf/C string len = 6000 114 ns 114 ns 6138575 BM_format/C string len = 6000 342 ns 342 ns 2047071 BM_format_to_back_inserter<std::string>/C string len = 6000 1011 ns 1011 ns 691579 BM_format_to_back_inserter<std::vector<char>>/C string len = 6000 991 ns 991 ns 711574 BM_format_to_back_inserter<std::deque<char>>/C string len = 6000 14990 ns 14990 ns 46648 BM_format_to_back_inserter<std::list<char>>/C string len = 6000 115092 ns 115090 ns 6097 BM_format_to_iterator/<std::array> C string len = 6000 159 ns 159 ns 4420990 BM_format_to_iterator/<std::string> C string len = 6000 147 ns 147 ns 4762118 BM_format_to_iterator/<std::vector> C string len = 6000 148 ns 148 ns 4733276 BM_format_to_iterator/<std::deque> C string len = 6000 308 ns 308 ns 2278285 BM_format/string len = 6000 291 ns 291 ns 2409136 BM_format_to_back_inserter<std::string>/string len = 6000 968 ns 968 ns 721845 BM_format_to_back_inserter<std::vector<char>>/string len = 6000 938 ns 938 ns 752091 BM_format_to_back_inserter<std::deque<char>>/string len = 6000 15029 ns 15030 ns 46591 BM_format_to_back_inserter<std::list<char>>/string len = 6000 115601 ns 115597 ns 6066 BM_format_to_iterator/<std::array> string len = 6000 118 ns 118 ns 5924962 BM_format_to_iterator/<std::string> string len = 6000 105 ns 105 ns 6630413 BM_format_to_iterator/<std::vector> string len = 6000 105 ns 105 ns 6628677 BM_format_to_iterator/<std::deque> string len = 6000 265 ns 265 ns 2684420 BM_format/string_view len = 6000 284 ns 284 ns 2461853 BM_format_to_back_inserter<std::string>/string_view len = 6000 969 ns 969 ns 724433 BM_format_to_back_inserter<std::vector<char>>/string_view len = 6000 938 ns 938 ns 749795 BM_format_to_back_inserter<std::deque<char>>/string_view len = 6000 14999 ns 14999 ns 46697 BM_format_to_back_inserter<std::list<char>>/string_view len = 6000 115524 ns 115520 ns 6033 BM_format_to_iterator/<std::array> string_view len = 6000 117 ns 117 ns 5982505 BM_format_to_iterator/<std::string> string_view len = 6000 105 ns 105 ns 6664752 BM_format_to_iterator/<std::vector> string_view len = 6000 105 ns 105 ns 6684043 BM_format_to_iterator/<std::deque> string_view len = 6000 256 ns 256 ns 2689843 Comparison Benchmark Time CPU Time Old Time New CPU Old CPU New ------------------------------------------------------------------------------------------------------------------------------------------------------------------- BM_sprintf/C string len = 6 -0.0037 -0.0051 4 4 4 4 BM_format/C string len = 6 -0.0022 -0.0037 50 49 50 49 BM_format_to_back_inserter<std::string>/C string len = 6 -0.0136 -0.0151 57 56 57 56 BM_format_to_back_inserter<std::vector<char>>/C string len = 6 +0.0408 +0.0392 73 76 73 76 BM_format_to_back_inserter<std::deque<char>>/C string len = 6 +0.0115 +0.0099 156 158 156 157 BM_format_to_back_inserter<std::list<char>>/C string len = 6 +0.0325 +0.0307 136 140 136 140 BM_format_to_iterator/<std::array> C string len = 6 -0.0153 -0.0167 47 46 47 46 BM_format_to_iterator/<std::string> C string len = 6 -0.0332 -0.0346 47 46 47 46 BM_format_to_iterator/<std::vector> C string len = 6 -0.0125 -0.0141 46 46 46 46 BM_format_to_iterator/<std::deque> C string len = 6 +0.0041 +0.0026 52 53 52 53 BM_format/string len = 6 -0.0170 -0.0185 50 49 50 49 BM_format_to_back_inserter<std::string>/string len = 6 -0.0092 -0.0106 56 55 56 55 BM_format_to_back_inserter<std::vector<char>>/string len = 6 +0.0153 +0.0138 73 74 73 74 BM_format_to_back_inserter<std::deque<char>>/string len = 6 +0.0392 +0.0371 155 161 154 160 BM_format_to_back_inserter<std::list<char>>/string len = 6 +0.0367 +0.0351 133 138 133 138 BM_format_to_iterator/<std::array> string len = 6 -0.0107 -0.0125 47 46 47 46 BM_format_to_iterator/<std::string> string len = 6 -0.0312 -0.0326 47 46 47 46 BM_format_to_iterator/<std::vector> string len = 6 -0.0103 -0.0144 46 46 46 46 BM_format_to_iterator/<std::deque> string len = 6 -0.0042 -0.0057 53 53 53 52 BM_format/string_view len = 6 -0.0191 -0.0206 49 48 49 48 BM_format_to_back_inserter<std::string>/string_view len = 6 -0.0283 -0.0298 56 55 56 54 BM_format_to_back_inserter<std::vector<char>>/string_view len = 6 +0.0408 +0.0389 72 75 72 75 BM_format_to_back_inserter<std::deque<char>>/string_view len = 6 +0.0214 +0.0199 153 157 153 156 BM_format_to_back_inserter<std::list<char>>/string_view len = 6 +0.0407 +0.0393 132 137 132 137 BM_format_to_iterator/<std::array> string_view len = 6 -0.0235 -0.0249 46 45 46 45 BM_format_to_iterator/<std::string> string_view len = 6 -0.0368 -0.0385 46 45 46 44 BM_format_to_iterator/<std::vector> string_view len = 6 -0.0293 -0.0308 46 45 46 45 BM_format_to_iterator/<std::deque> string_view len = 6 +0.0094 +0.0079 52 52 52 52 BM_sprintf/C string len = 60 -0.0004 -0.0018 5 5 5 5 BM_format/C string len = 60 +0.0250 +0.0232 64 65 64 65 BM_format_to_back_inserter<std::string>/C string len = 60 -0.0027 -0.0041 75 75 75 75 BM_format_to_back_inserter<std::vector<char>>/C string len = 60 +0.0228 +0.0233 89 91 89 91 BM_format_to_back_inserter<std::deque<char>>/C string len = 60 +0.0303 +0.0312 285 294 285 294 BM_format_to_back_inserter<std::list<char>>/C string len = 60 +0.0419 +0.0429 1164 1212 1163 1212 BM_format_to_iterator/<std::array> C string len = 60 -0.0154 -0.0145 46 46 46 46 BM_format_to_iterator/<std::string> C string len = 60 -0.0355 -0.0345 47 45 47 45 BM_format_to_iterator/<std::vector> C string len = 60 -0.0161 -0.0152 46 46 46 46 BM_format_to_iterator/<std::deque> C string len = 60 +0.0044 +0.0054 52 52 52 52 BM_format/string len = 60 +0.0268 +0.0278 62 64 62 64 BM_format_to_back_inserter<std::string>/string len = 60 -0.0031 -0.0022 75 74 75 74 BM_format_to_back_inserter<std::vector<char>>/string len = 60 +0.0183 +0.0191 87 88 86 88 BM_format_to_back_inserter<std::deque<char>>/string len = 60 +0.0567 +0.0578 279 295 279 295 BM_format_to_back_inserter<std::list<char>>/string len = 60 +0.0386 +0.0396 1167 1212 1165 1212 BM_format_to_iterator/<std::array> string len = 60 -0.0094 -0.0084 47 46 47 46 BM_format_to_iterator/<std::string> string len = 60 -0.0268 -0.0259 47 46 47 46 BM_format_to_iterator/<std::vector> string len = 60 -0.0082 -0.0073 46 46 46 46 BM_format_to_iterator/<std::deque> string len = 60 +0.0254 +0.0264 52 54 52 54 BM_format/string_view len = 60 -0.0084 -0.0075 62 62 62 62 BM_format_to_back_inserter<std::string>/string_view len = 60 -0.0001 +0.0008 74 74 74 74 BM_format_to_back_inserter<std::vector<char>>/string_view len = 60 +0.0145 +0.0154 86 88 86 88 BM_format_to_back_inserter<std::deque<char>>/string_view len = 60 +0.0411 +0.0420 279 291 279 291 BM_format_to_back_inserter<std::list<char>>/string_view len = 60 +0.0358 +0.0368 1164 1205 1163 1205 BM_format_to_iterator/<std::array> string_view len = 60 -0.0306 -0.0297 47 45 47 45 BM_format_to_iterator/<std::string> string_view len = 60 -0.0321 -0.0312 46 45 46 45 BM_format_to_iterator/<std::vector> string_view len = 60 -0.0320 -0.0311 46 45 46 45 BM_format_to_iterator/<std::deque> string_view len = 60 +0.0039 +0.0048 52 52 52 52 BM_sprintf/C string len = 6000 +0.4788 +0.4802 77 114 77 114 BM_format/C string len = 6000 -0.0087 -0.0078 345 342 345 342 BM_format_to_back_inserter<std::string>/C string len = 6000 +0.0104 +0.0114 1001 1011 1000 1011 BM_format_to_back_inserter<std::vector<char>>/C string len = 6000 +0.0195 +0.0206 972 991 971 991 BM_format_to_back_inserter<std::deque<char>>/C string len = 6000 -0.0092 -0.0082 15129 14990 15114 14990 BM_format_to_back_inserter<std::list<char>>/C string len = 6000 -0.0017 -0.0007 115290 115092 115167 115090 BM_format_to_iterator/<std::array> C string len = 6000 -0.0136 -0.0127 161 159 161 159 BM_format_to_iterator/<std::string> C string len = 6000 -0.0442 -0.0433 154 147 154 147 BM_format_to_iterator/<std::vector> C string len = 6000 -0.0148 -0.0139 150 148 150 148 BM_format_to_iterator/<std::deque> C string len = 6000 -0.3357 -0.3350 463 308 463 308 BM_format/string len = 6000 +0.0329 +0.0341 282 291 281 291 BM_format_to_back_inserter<std::string>/string len = 6000 +0.0289 +0.0299 941 968 940 968 BM_format_to_back_inserter<std::vector<char>>/string len = 6000 +0.0058 +0.0068 933 938 932 938 BM_format_to_back_inserter<std::deque<char>>/string len = 6000 -0.0053 -0.0043 15110 15029 15095 15030 BM_format_to_back_inserter<std::list<char>>/string len = 6000 +0.0041 +0.0065 115131 115601 114854 115597 BM_format_to_iterator/<std::array> string len = 6000 -0.0028 +0.0000 119 118 118 118 BM_format_to_iterator/<std::string> string len = 6000 -0.0214 -0.0190 108 105 107 105 BM_format_to_iterator/<std::vector> string len = 6000 -0.0125 -0.0100 107 105 107 105 BM_format_to_iterator/<std::deque> string len = 6000 -0.3286 -0.3269 395 265 394 265 BM_format/string_view len = 6000 +0.0084 +0.0110 282 284 281 284 BM_format_to_back_inserter<std::string>/string_view len = 6000 +0.0347 +0.0373 936 969 934 969 BM_format_to_back_inserter<std::vector<char>>/string_view len = 6000 +0.0148 +0.0173 925 938 922 938 BM_format_to_back_inserter<std::deque<char>>/string_view len = 6000 -0.0049 -0.0025 15072 14999 15036 14999 BM_format_to_back_inserter<std::list<char>>/string_view len = 6000 +0.0017 +0.0040 115332 115524 115059 115520 BM_format_to_iterator/<std::array> string_view len = 6000 -0.0174 -0.0147 119 117 119 117 BM_format_to_iterator/<std::string> string_view len = 6000 -0.0269 -0.0245 108 105 107 105 BM_format_to_iterator/<std::vector> string_view len = 6000 -0.0226 -0.0202 107 105 107 105 BM_format_to_iterator/<std::deque> string_view len = 6000 -0.3463 -0.3447 392 256 391 256 OVERALL_GEOMEAN -0.0089 -0.0087 0 0 0 0 format_to: Before -------------------------------------------------------------------------------------------------------------------------- Benchmark Time CPU Iterations UserCounters... -------------------------------------------------------------------------------------------------------------------------- BM_format_to_string_back_inserter<std::string>/1 55.3 ns 55.2 ns 12600282 bytes_per_second=17.2841Mi/s BM_format_to_string_back_inserter<std::string>/2 55.3 ns 55.2 ns 12711392 bytes_per_second=34.584Mi/s BM_format_to_string_back_inserter<std::string>/4 55.3 ns 55.2 ns 12668346 bytes_per_second=69.1337Mi/s BM_format_to_string_back_inserter<std::string>/8 55.0 ns 54.8 ns 12806254 bytes_per_second=139.148Mi/s BM_format_to_string_back_inserter<std::string>/16 55.0 ns 54.9 ns 12771640 bytes_per_second=278.038Mi/s BM_format_to_string_back_inserter<std::string>/32 74.3 ns 74.1 ns 9425332 bytes_per_second=411.691Mi/s BM_format_to_string_back_inserter<std::string>/64 74.3 ns 74.1 ns 9467958 bytes_per_second=823.72Mi/s BM_format_to_string_back_inserter<std::string>/128 75.6 ns 75.4 ns 9244814 bytes_per_second=1.58012Gi/s BM_format_to_string_back_inserter<std::string>/256 90.4 ns 90.1 ns 7758708 bytes_per_second=2.64476Gi/s BM_format_to_string_back_inserter<std::string>/512 136 ns 135 ns 5171079 bytes_per_second=3.52016Gi/s BM_format_to_string_back_inserter<std::string>/1024 253 ns 252 ns 2766944 bytes_per_second=3.77704Gi/s BM_format_to_string_back_inserter<std::string>/2048 410 ns 409 ns 1711155 bytes_per_second=4.66192Gi/s BM_format_to_string_back_inserter<std::string>/4096 662 ns 660 ns 1063114 bytes_per_second=5.77795Gi/s BM_format_to_string_back_inserter<std::string>/8192 1124 ns 1121 ns 626215 bytes_per_second=6.80694Gi/s BM_format_to_string_back_inserter<std::string>/16384 2228 ns 2222 ns 315523 bytes_per_second=6.86706Gi/s BM_format_to_string_back_inserter<std::string>/32768 4795 ns 4783 ns 146357 bytes_per_second=6.38068Gi/s BM_format_to_string_back_inserter<std::string>/65536 8433 ns 8412 ns 83268 bytes_per_second=7.25532Gi/s BM_format_to_string_back_inserter<std::string>/131072 44973 ns 44732 ns 15650 bytes_per_second=2.7289Gi/s BM_format_to_string_back_inserter<std::string>/262144 134871 ns 134517 ns 5205 bytes_per_second=1.81495Gi/s BM_format_to_string_back_inserter<std::string>/524288 316669 ns 316613 ns 2208 bytes_per_second=1.5422Gi/s BM_format_to_string_back_inserter<std::string>/1048576 677580 ns 677582 ns 1036 bytes_per_second=1.44125Gi/s BM_format_to_string_back_inserter<std::vector<char>>/1 69.9 ns 69.9 ns 9994480 bytes_per_second=13.6348Mi/s BM_format_to_string_back_inserter<std::vector<char>>/2 70.1 ns 70.1 ns 9995724 bytes_per_second=27.2205Mi/s BM_format_to_string_back_inserter<std::vector<char>>/4 71.3 ns 71.3 ns 9850375 bytes_per_second=53.5283Mi/s BM_format_to_string_back_inserter<std::vector<char>>/8 73.8 ns 73.8 ns 9486647 bytes_per_second=103.44Mi/s BM_format_to_string_back_inserter<std::vector<char>>/16 78.7 ns 78.7 ns 8873541 bytes_per_second=193.765Mi/s BM_format_to_string_back_inserter<std::vector<char>>/32 88.7 ns 88.7 ns 7913676 bytes_per_second=344.039Mi/s BM_format_to_string_back_inserter<std::vector<char>>/64 90.2 ns 90.2 ns 7740112 bytes_per_second=676.676Mi/s BM_format_to_string_back_inserter<std::vector<char>>/128 92.2 ns 92.2 ns 7569110 bytes_per_second=1.29352Gi/s BM_format_to_string_back_inserter<std::vector<char>>/256 106 ns 106 ns 6612544 bytes_per_second=2.25002Gi/s BM_format_to_string_back_inserter<std::vector<char>>/512 163 ns 163 ns 4299613 bytes_per_second=2.9327Gi/s BM_format_to_string_back_inserter<std::vector<char>>/1024 240 ns 240 ns 2919691 bytes_per_second=3.98065Gi/s BM_format_to_string_back_inserter<std::vector<char>>/2048 400 ns 400 ns 1749907 bytes_per_second=4.76489Gi/s BM_format_to_string_back_inserter<std::vector<char>>/4096 635 ns 635 ns 1101669 bytes_per_second=6.00718Gi/s BM_format_to_string_back_inserter<std::vector<char>>/8192 1064 ns 1064 ns 655668 bytes_per_second=7.17313Gi/s BM_format_to_string_back_inserter<std::vector<char>>/16384 1986 ns 1986 ns 352665 bytes_per_second=7.68268Gi/s BM_format_to_string_back_inserter<std::vector<char>>/32768 3834 ns 3835 ns 182295 bytes_per_second=7.95861Gi/s BM_format_to_string_back_inserter<std::vector<char>>/65536 7388 ns 7388 ns 94038 bytes_per_second=8.26153Gi/s BM_format_to_string_back_inserter<std::vector<char>>/131072 17454 ns 17454 ns 40109 bytes_per_second=6.99363Gi/s BM_format_to_string_back_inserter<std::vector<char>>/262144 36133 ns 36133 ns 19353 bytes_per_second=6.75666Gi/s BM_format_to_string_back_inserter<std::vector<char>>/524288 73310 ns 73310 ns 9556 bytes_per_second=6.66053Gi/s BM_format_to_string_back_inserter<std::vector<char>>/1048576 145001 ns 144996 ns 4828 bytes_per_second=6.73509Gi/s BM_format_to_string_back_inserter<std::list<char>>/1 62.9 ns 62.9 ns 11119088 bytes_per_second=15.1622Mi/s BM_format_to_string_back_inserter<std::list<char>>/2 76.0 ns 76.0 ns 9212976 bytes_per_second=25.0904Mi/s BM_format_to_string_back_inserter<std::list<char>>/4 103 ns 103 ns 6740929 bytes_per_second=36.8618Mi/s BM_format_to_string_back_inserter<std::list<char>>/8 171 ns 171 ns 4096894 bytes_per_second=44.6147Mi/s BM_format_to_string_back_inserter<std::list<char>>/16 324 ns 324 ns 2147006 bytes_per_second=47.0328Mi/s BM_format_to_string_back_inserter<std::list<char>>/32 638 ns 638 ns 1096597 bytes_per_second=47.799Mi/s BM_format_to_string_back_inserter<std::list<char>>/64 1230 ns 1230 ns 570396 bytes_per_second=49.6318Mi/s BM_format_to_string_back_inserter<std::list<char>>/128 2427 ns 2427 ns 289550 bytes_per_second=50.306Mi/s BM_format_to_string_back_inserter<std::list<char>>/256 4847 ns 4847 ns 144614 bytes_per_second=50.3648Mi/s BM_format_to_string_back_inserter<std::list<char>>/512 9656 ns 9656 ns 72476 bytes_per_second=50.5676Mi/s BM_format_to_string_back_inserter<std::list<char>>/1024 19415 ns 19416 ns 35934 bytes_per_second=50.298Mi/s BM_format_to_string_back_inserter<std::list<char>>/2048 38927 ns 38928 ns 17986 bytes_per_second=50.173Mi/s BM_format_to_string_back_inserter<std::list<char>>/4096 78062 ns 78064 ns 8967 bytes_per_second=50.0392Mi/s BM_format_to_string_back_inserter<std::list<char>>/8192 156624 ns 156628 ns 4464 bytes_per_second=49.8795Mi/s BM_format_to_string_back_inserter<std::list<char>>/16384 313781 ns 313788 ns 2232 bytes_per_second=49.7948Mi/s BM_format_to_string_back_inserter<std::list<char>>/32768 626674 ns 626667 ns 1112 bytes_per_second=49.867Mi/s BM_format_to_string_back_inserter<std::list<char>>/65536 1248918 ns 1248933 ns 558 bytes_per_second=50.0427Mi/s BM_format_to_string_back_inserter<std::list<char>>/131072 2512031 ns 2511949 ns 277 bytes_per_second=49.7622Mi/s BM_format_to_string_back_inserter<std::list<char>>/262144 5118786 ns 5118308 ns 126 bytes_per_second=48.8443Mi/s BM_format_to_string_back_inserter<std::list<char>>/524288 10395742 ns 10395288 ns 63 bytes_per_second=48.0987Mi/s BM_format_to_string_back_inserter<std::list<char>>/1048576 21110172 ns 21110073 ns 31 bytes_per_second=47.3708Mi/s BM_format_to_string_begin<std::string>/1 47.0 ns 47.0 ns 14928464 bytes_per_second=20.2942Mi/s BM_format_to_string_begin<std::string>/2 47.0 ns 47.0 ns 14889677 bytes_per_second=40.5641Mi/s BM_format_to_string_begin<std::string>/4 47.1 ns 47.1 ns 14877893 bytes_per_second=81.0735Mi/s BM_format_to_string_begin<std::string>/8 47.0 ns 47.0 ns 14855791 bytes_per_second=162.307Mi/s BM_format_to_string_begin<std::string>/16 47.1 ns 47.1 ns 14867291 bytes_per_second=324.274Mi/s BM_format_to_string_begin<std::string>/32 47.0 ns 47.0 ns 14863938 bytes_per_second=649.013Mi/s BM_format_to_string_begin<std::string>/64 46.5 ns 46.5 ns 14004459 bytes_per_second=1.28171Gi/s BM_format_to_string_begin<std::string>/128 47.1 ns 47.1 ns 14831108 bytes_per_second=2.53299Gi/s BM_format_to_string_begin<std::string>/256 51.6 ns 51.6 ns 13604783 bytes_per_second=4.62228Gi/s BM_format_to_string_begin<std::string>/512 50.0 ns 50.0 ns 13980138 bytes_per_second=9.53155Gi/s BM_format_to_string_begin<std::string>/1024 59.2 ns 59.2 ns 11872452 bytes_per_second=16.1221Gi/s BM_format_to_string_begin<std::string>/2048 69.0 ns 69.0 ns 10128771 bytes_per_second=27.6377Gi/s BM_format_to_string_begin<std::string>/4096 100 ns 100 ns 6963452 bytes_per_second=38.0663Gi/s BM_format_to_string_begin<std::string>/8192 151 ns 151 ns 4635381 bytes_per_second=50.5416Gi/s BM_format_to_string_begin<std::string>/16384 314 ns 314 ns 2233442 bytes_per_second=48.5983Gi/s BM_format_to_string_begin<std::string>/32768 1336 ns 1336 ns 524989 bytes_per_second=22.8492Gi/s BM_format_to_string_begin<std::string>/65536 3763 ns 3763 ns 185762 bytes_per_second=16.2188Gi/s BM_format_to_string_begin<std::string>/131072 6556 ns 6556 ns 106616 bytes_per_second=18.6207Gi/s BM_format_to_string_begin<std::string>/262144 13979 ns 13979 ns 50149 bytes_per_second=17.4643Gi/s BM_format_to_string_begin<std::string>/524288 28719 ns 28719 ns 24379 bytes_per_second=17.0019Gi/s BM_format_to_string_begin<std::string>/1048576 57299 ns 57299 ns 12180 bytes_per_second=17.0432Gi/s BM_format_to_string_begin<std::vector<char>>/1 46.1 ns 46.1 ns 15188343 bytes_per_second=20.6809Mi/s BM_format_to_string_begin<std::vector<char>>/2 46.1 ns 46.1 ns 15158904 bytes_per_second=41.3318Mi/s BM_format_to_string_begin<std::vector<char>>/4 46.1 ns 46.1 ns 15170378 bytes_per_second=82.6776Mi/s BM_format_to_string_begin<std::vector<char>>/8 45.7 ns 45.7 ns 15315671 bytes_per_second=167.026Mi/s BM_format_to_string_begin<std::vector<char>>/16 46.2 ns 46.2 ns 15163881 bytes_per_second=330.559Mi/s BM_format_to_string_begin<std::vector<char>>/32 46.1 ns 46.1 ns 15201091 bytes_per_second=661.98Mi/s BM_format_to_string_begin<std::vector<char>>/64 46.2 ns 46.2 ns 14183997 bytes_per_second=1.28927Gi/s BM_format_to_string_begin<std::vector<char>>/128 46.7 ns 46.7 ns 14987395 bytes_per_second=2.55007Gi/s BM_format_to_string_begin<std::vector<char>>/256 51.3 ns 51.3 ns 13898949 bytes_per_second=4.64462Gi/s BM_format_to_string_begin<std::vector<char>>/512 50.1 ns 50.1 ns 10000000 bytes_per_second=9.52165Gi/s BM_format_to_string_begin<std::vector<char>>/1024 59.2 ns 59.2 ns 11805042 bytes_per_second=16.105Gi/s BM_format_to_string_begin<std::vector<char>>/2048 69.0 ns 69.0 ns 10139614 bytes_per_second=27.6266Gi/s BM_format_to_string_begin<std::vector<char>>/4096 97.6 ns 97.6 ns 7179535 bytes_per_second=39.0938Gi/s BM_format_to_string_begin<std::vector<char>>/8192 152 ns 152 ns 4610486 bytes_per_second=50.227Gi/s BM_format_to_string_begin<std::vector<char>>/16384 314 ns 314 ns 2230251 bytes_per_second=48.5946Gi/s BM_format_to_string_begin<std::vector<char>>/32768 1333 ns 1333 ns 525550 bytes_per_second=22.8868Gi/s BM_format_to_string_begin<std::vector<char>>/65536 3760 ns 3760 ns 185821 bytes_per_second=16.2322Gi/s BM_format_to_string_begin<std::vector<char>>/131072 6479 ns 6480 ns 107960 bytes_per_second=18.8391Gi/s BM_format_to_string_begin<std::vector<char>>/262144 14164 ns 14164 ns 49862 bytes_per_second=17.2368Gi/s BM_format_to_string_begin<std::vector<char>>/524288 28916 ns 28916 ns 24149 bytes_per_second=16.8861Gi/s BM_format_to_string_begin<std::vector<char>>/1048576 57621 ns 57622 ns 12140 bytes_per_second=16.9478Gi/s BM_format_to_string_begin<std::list<char>>/1 47.6 ns 47.6 ns 14675857 bytes_per_second=20.0271Mi/s BM_format_to_string_begin<std::list<char>>/2 48.8 ns 48.8 ns 14331930 bytes_per_second=39.1155Mi/s BM_format_to_string_begin<std::list<char>>/4 50.9 ns 50.9 ns 13747606 bytes_per_second=74.9309Mi/s BM_format_to_string_begin<std::list<char>>/8 63.4 ns 63.4 ns 11065440 bytes_per_second=120.329Mi/s BM_format_to_string_begin<std::list<char>>/16 82.4 ns 82.4 ns 8510480 bytes_per_second=185.222Mi/s BM_format_to_string_begin<std::list<char>>/32 126 ns 126 ns 5564932 bytes_per_second=242.653Mi/s BM_format_to_string_begin<std::list<char>>/64 211 ns 211 ns 3311820 bytes_per_second=289.214Mi/s BM_format_to_string_begin<std::list<char>>/128 384 ns 384 ns 1825012 bytes_per_second=318.238Mi/s BM_format_to_string_begin<std::list<char>>/256 735 ns 735 ns 951285 bytes_per_second=332.108Mi/s BM_format_to_string_begin<std::list<char>>/512 1428 ns 1428 ns 489437 bytes_per_second=341.969Mi/s BM_format_to_string_begin<std::list<char>>/1024 2792 ns 2792 ns 242406 bytes_per_second=349.822Mi/s BM_format_to_string_begin<std::list<char>>/2048 5594 ns 5594 ns 124188 bytes_per_second=349.129Mi/s BM_format_to_string_begin<std::list<char>>/4096 11163 ns 11163 ns 62794 bytes_per_second=349.936Mi/s BM_format_to_string_begin<std::list<char>>/8192 22339 ns 22339 ns 31335 bytes_per_second=349.718Mi/s BM_format_to_string_begin<std::list<char>>/16384 44673 ns 44674 ns 15675 bytes_per_second=349.754Mi/s BM_format_to_string_begin<std::list<char>>/32768 89015 ns 89016 ns 7849 bytes_per_second=351.06Mi/s BM_format_to_string_begin<std::list<char>>/65536 177988 ns 177989 ns 3938 bytes_per_second=351.145Mi/s BM_format_to_string_begin<std::list<char>>/131072 362715 ns 362697 ns 1933 bytes_per_second=344.64Mi/s BM_format_to_string_begin<std::list<char>>/262144 846730 ns 846685 ns 825 bytes_per_second=295.269Mi/s BM_format_to_string_begin<std::list<char>>/524288 2018755 ns 2018721 ns 347 bytes_per_second=247.682Mi/s BM_format_to_string_begin<std::list<char>>/1048576 4225251 ns 4225188 ns 165 bytes_per_second=236.676Mi/s BM_format_to_string_span<char>/1 46.2 ns 46.2 ns 15156896 bytes_per_second=20.6258Mi/s BM_format_to_string_span<char>/2 46.3 ns 46.3 ns 15114242 bytes_per_second=41.1559Mi/s BM_format_to_string_span<char>/4 46.4 ns 46.4 ns 15089475 bytes_per_second=82.1686Mi/s BM_format_to_string_span<char>/8 45.9 ns 45.9 ns 15249334 bytes_per_second=166.143Mi/s BM_format_to_string_span<char>/16 46.3 ns 46.3 ns 15087074 bytes_per_second=329.233Mi/s BM_format_to_string_span<char>/32 46.4 ns 46.4 ns 15099464 bytes_per_second=657.611Mi/s BM_format_to_string_span<char>/64 46.4 ns 46.4 ns 14101746 bytes_per_second=1.2849Gi/s BM_format_to_string_span<char>/128 47.0 ns 47.0 ns 14919410 bytes_per_second=2.53769Gi/s BM_format_to_string_span<char>/256 50.8 ns 50.8 ns 13874090 bytes_per_second=4.69274Gi/s BM_format_to_string_span<char>/512 50.5 ns 50.5 ns 13849265 bytes_per_second=9.44604Gi/s BM_format_to_string_span<char>/1024 59.6 ns 59.6 ns 11774716 bytes_per_second=16.008Gi/s BM_format_to_string_span<char>/2048 69.3 ns 69.3 ns 10102354 bytes_per_second=27.5137Gi/s BM_format_to_string_span<char>/4096 98.0 ns 98.0 ns 7137947 bytes_per_second=38.9144Gi/s BM_format_to_string_span<char>/8192 153 ns 153 ns 4585057 bytes_per_second=49.9901Gi/s BM_format_to_string_span<char>/16384 316 ns 316 ns 2225896 bytes_per_second=48.3398Gi/s BM_format_to_string_span<char>/32768 1339 ns 1339 ns 520365 bytes_per_second=22.7872Gi/s BM_format_to_string_span<char>/65536 3780 ns 3780 ns 184720 bytes_per_second=16.1474Gi/s BM_format_to_string_span<char>/131072 6557 ns 6557 ns 106444 bytes_per_second=18.6157Gi/s BM_format_to_string_span<char>/262144 14199 ns 14199 ns 49363 bytes_per_second=17.1939Gi/s BM_format_to_string_span<char>/524288 28833 ns 28834 ns 24254 bytes_per_second=16.9343Gi/s BM_format_to_string_span<char>/1048576 57660 ns 57660 ns 12166 bytes_per_second=16.9365Gi/s BM_format_to_string_pointer<char>/1 46.4 ns 46.4 ns 15070582 bytes_per_second=20.5355Mi/s BM_format_to_string_pointer<char>/2 46.5 ns 46.5 ns 15064611 bytes_per_second=41.0239Mi/s BM_format_to_string_pointer<char>/4 46.4 ns 46.4 ns 15080092 bytes_per_second=82.1674Mi/s BM_format_to_string_pointer<char>/8 45.9 ns 45.9 ns 15239465 bytes_per_second=166.094Mi/s BM_format_to_string_pointer<char>/16 46.4 ns 46.4 ns 15077440 bytes_per_second=328.884Mi/s BM_format_to_string_pointer<char>/32 46.4 ns 46.4 ns 15070278 bytes_per_second=657.438Mi/s BM_format_to_string_pointer<char>/64 46.4 ns 46.4 ns 14094814 bytes_per_second=1.28358Gi/s BM_format_to_string_pointer<char>/128 46.8 ns 46.8 ns 14894522 bytes_per_second=2.54466Gi/s BM_format_to_string_pointer<char>/256 51.2 ns 51.2 ns 13908865 bytes_per_second=4.65713Gi/s BM_format_to_string_pointer<char>/512 50.2 ns 50.2 ns 13999036 bytes_per_second=9.5049Gi/s BM_format_to_string_pointer<char>/1024 59.4 ns 59.4 ns 11805502 bytes_per_second=16.0611Gi/s BM_format_to_string_pointer<char>/2048 69.1 ns 69.1 ns 10114415 bytes_per_second=27.5936Gi/s BM_format_to_string_pointer<char>/4096 97.6 ns 97.6 ns 7154104 bytes_per_second=39.0914Gi/s BM_format_to_string_pointer<char>/8192 151 ns 151 ns 4653492 bytes_per_second=50.6101Gi/s BM_format_to_string_pointer<char>/16384 314 ns 314 ns 2222259 bytes_per_second=48.6129Gi/s BM_format_to_string_pointer<char>/32768 1336 ns 1336 …
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2 files changed

+93
-2
lines changed

2 files changed

+93
-2
lines changed

‎libcxx/include/__format/buffer.h‎

Lines changed: 91 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -14,6 +14,7 @@
1414
#include <__algorithm/fill_n.h>
1515
#include <__algorithm/max.h>
1616
#include <__algorithm/min.h>
17+
#include <__algorithm/ranges_copy.h>
1718
#include <__algorithm/ranges_copy_n.h>
1819
#include <__algorithm/transform.h>
1920
#include <__algorithm/unwrap_iter.h>
@@ -39,6 +40,7 @@
3940
#include <__utility/exception_guard.h>
4041
#include <__utility/move.h>
4142
#include <cstddef>
43+
#include <stdexcept>
4244
#include <string_view>
4345

4446
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -722,6 +724,95 @@ class _LIBCPP_TEMPLATE_VIS __allocating_buffer : public __output_buffer<_CharT>
722724
}
723725
};
724726

727+
// A buffer that directly writes to the underlying buffer.
728+
template <class _OutIt, __fmt_char_type _CharT>
729+
class _LIBCPP_TEMPLATE_VIS __direct_iterator_buffer : public __output_buffer<_CharT> {
730+
public:
731+
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI explicit __direct_iterator_buffer(_OutIt __out_it)
732+
: __output_buffer<_CharT>{std::__unwrap_iter(__out_it), __buffer_size, __prepare_write}, __out_it_(__out_it) {}
733+
734+
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI _OutIt __out_it() && { return __out_it_ + this->__size(); }
735+
736+
private:
737+
// The function format_to expects a buffer large enough for the output. The
738+
// function format_to_n has its own helper class that restricts the number of
739+
// write options. So this function class can pretend to have an infinite
740+
// buffer.
741+
static constexpr size_t __buffer_size = -1;
742+
743+
_OutIt __out_it_;
744+
745+
_LIBCPP_HIDE_FROM_ABI static void
746+
__prepare_write([[maybe_unused]] __output_buffer<_CharT>& __buffer, [[maybe_unused]] size_t __size_hint) {
747+
std::__throw_length_error("__direct_iterator_buffer");
748+
}
749+
};
750+
751+
// A buffer that writes its output to the end of a container.
752+
template <class _OutIt, __fmt_char_type _CharT>
753+
class _LIBCPP_TEMPLATE_VIS __container_inserter_buffer : public __output_buffer<_CharT> {
754+
public:
755+
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI explicit __container_inserter_buffer(_OutIt __out_it)
756+
: __output_buffer<_CharT>{__buffer_, __buffer_size, __prepare_write}, __container_{__out_it.__get_container()} {}
757+
758+
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI auto __out_it() && {
759+
__container_->insert(__container_->end(), __buffer_, __buffer_ + this->__size());
760+
return std::back_inserter(*__container_);
761+
}
762+
763+
private:
764+
typename __back_insert_iterator_container<_OutIt>::type* __container_;
765+
766+
// This class uses a fixed size buffer and appends the elements in
767+
// __buffer_size chunks. An alternative would be to use an allocating buffer
768+
// and append the output in one write operation. Benchmarking showed no
769+
// performance difference.
770+
static constexpr size_t __buffer_size = 256;
771+
_CharT __buffer_[__buffer_size];
772+
773+
_LIBCPP_HIDE_FROM_ABI void __prepare_write() {
774+
__container_->insert(__container_->end(), __buffer_, __buffer_ + this->__size());
775+
this->__buffer_flused();
776+
}
777+
778+
_LIBCPP_HIDE_FROM_ABI static void
779+
__prepare_write(__output_buffer<_CharT>& __buffer, [[maybe_unused]] size_t __size_hint) {
780+
static_cast<__container_inserter_buffer<_OutIt, _CharT>&>(__buffer).__prepare_write();
781+
}
782+
};
783+
784+
// A buffer that writes to an iterator.
785+
//
786+
// Unlinke the __container_inserter_buffer this class' perfomance does benefit
787+
// from allocating and then inserting.
788+
template <class _OutIt, __fmt_char_type _CharT>
789+
class _LIBCPP_TEMPLATE_VIS __iterator_buffer : public __allocating_buffer<_CharT> {
790+
public:
791+
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI explicit __iterator_buffer(_OutIt __out_it)
792+
: __allocating_buffer<_CharT>{}, __out_it_{std::move(__out_it)} {}
793+
794+
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI auto __out_it() && {
795+
return std::ranges::copy(this->__view(), std::move(__out_it_)).out;
796+
}
797+
798+
private:
799+
_OutIt __out_it_;
800+
};
801+
802+
// Selects the type of the buffer used for the output iterator.
803+
template <class _OutIt, __fmt_char_type _CharT>
804+
class _LIBCPP_TEMPLATE_VIS __buffer_selector {
805+
using _Container = __back_insert_iterator_container<_OutIt>::type;
806+
807+
public:
808+
using type =
809+
conditional_t<!same_as<_Container, void>,
810+
__container_inserter_buffer<_OutIt, _CharT>,
811+
conditional_t<__enable_direct_output<_OutIt, _CharT>,
812+
__direct_iterator_buffer<_OutIt, _CharT>,
813+
__iterator_buffer<_OutIt, _CharT>>>;
814+
};
815+
725816
// ***** ***** ***** LLVM-19 and LLVM-20 class ***** ***** *****
726817

727818
// A dynamically growing buffer intended to be used for retargeting a context.

‎libcxx/include/__format/format_functions.h‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -411,7 +411,7 @@ _LIBCPP_HIDE_FROM_ABI _OutIt __vformat_to(_OutIt __out_it,
411411
return std::__format::__vformat_to(
412412
basic_format_parse_context{__fmt, __args.__size()}, std::__format_context_create(std::move(__out_it), __args));
413413
else {
414-
__format::__format_buffer<_OutIt, _CharT> __buffer{std::move(__out_it)};
414+
typename __format::__buffer_selector<_OutIt, _CharT>::type __buffer{std::move(__out_it)};
415415
std::__format::__vformat_to(basic_format_parse_context{__fmt, __args.__size()},
416416
std::__format_context_create(__buffer.__make_output_iterator(), __args));
417417
return std::move(__buffer).__out_it();
@@ -544,7 +544,7 @@ _LIBCPP_HIDE_FROM_ABI _OutIt __vformat_to(
544544
return std::__format::__vformat_to(basic_format_parse_context{__fmt, __args.__size()},
545545
std::__format_context_create(std::move(__out_it), __args, std::move(__loc)));
546546
else {
547-
__format::__format_buffer<_OutIt, _CharT> __buffer{std::move(__out_it)};
547+
typename __format::__buffer_selector<_OutIt, _CharT>::type __buffer{std::move(__out_it)};
548548
std::__format::__vformat_to(
549549
basic_format_parse_context{__fmt, __args.__size()},
550550
std::__format_context_create(__buffer.__make_output_iterator(), __args, std::move(__loc)));

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