ruby.git/ext/bigdecimal/missing, branch v3_3_11 The Ruby Programming Language [ruby/bigdecimal] Optimize rb_float_convert_to_BigDecimal by using dtoa 2021-01-12T17:11:18+00:00 Kenta Murata mrkn@mrkn.jp 2021-01-12T13:58:17+00:00 4ba3a4491e15ed50f26c8f7a602fb4ef5452085a This improve the conversion speed several times faster than before. ``` RUBYLIB= BUNDLER_ORIG_RUBYLIB= /home/mrkn/.rbenv/versions/3.0.0/bin/ruby -v -S benchmark-driver /home/mrkn/src/github.com/ruby/bigdecimal/benchmark/from_float.yml ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-linux] Calculating ------------------------------------- bigdecimal 3.0.0 master flt_e0 156.400k 783.356k i/s - 100.000k times in 0.639388s 0.127656s flt_ep10 158.640k 777.978k i/s - 100.000k times in 0.630359s 0.128538s flt_ep100 101.676k 504.259k i/s - 100.000k times in 0.983512s 0.198311s flt_em10 103.439k 726.339k i/s - 100.000k times in 0.966751s 0.137677s flt_em100 79.675k 651.446k i/s - 100.000k times in 1.255095s 0.153505s Comparison: flt_e0 master: 783355.6 i/s bigdecimal 3.0.0: 156399.5 i/s - 5.01x slower flt_ep10 master: 777977.6 i/s bigdecimal 3.0.0: 158639.7 i/s - 4.90x slower flt_ep100 master: 504259.4 i/s bigdecimal 3.0.0: 101676.5 i/s - 4.96x slower flt_em10 master: 726338.6 i/s bigdecimal 3.0.0: 103439.2 i/s - 7.02x slower flt_em100 master: 651446.3 i/s bigdecimal 3.0.0: 79675.3 i/s - 8.18x slower ``` https://github.com/ruby/bigdecimal/commit/5bdaedd530 https://github.com/ruby/bigdecimal/commit/9bfff57f90 https://github.com/ruby/bigdecimal/commit/d071a0abbb 
This improve the conversion speed several times faster than before.

```
RUBYLIB= BUNDLER_ORIG_RUBYLIB= /home/mrkn/.rbenv/versions/3.0.0/bin/ruby -v -S benchmark-driver /home/mrkn/src/github.com/ruby/bigdecimal/benchmark/from_float.yml
ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-linux]
Calculating -------------------------------------
                     bigdecimal 3.0.0      master
              flt_e0         156.400k    783.356k i/s -    100.000k times in 0.639388s 0.127656s
            flt_ep10         158.640k    777.978k i/s -    100.000k times in 0.630359s 0.128538s
           flt_ep100         101.676k    504.259k i/s -    100.000k times in 0.983512s 0.198311s
            flt_em10         103.439k    726.339k i/s -    100.000k times in 0.966751s 0.137677s
           flt_em100          79.675k    651.446k i/s -    100.000k times in 1.255095s 0.153505s

Comparison:
                           flt_e0
              master:    783355.6 i/s
    bigdecimal 3.0.0:    156399.5 i/s - 5.01x  slower

                         flt_ep10
              master:    777977.6 i/s
    bigdecimal 3.0.0:    158639.7 i/s - 4.90x  slower

                        flt_ep100
              master:    504259.4 i/s
    bigdecimal 3.0.0:    101676.5 i/s - 4.96x  slower

                         flt_em10
              master:    726338.6 i/s
    bigdecimal 3.0.0:    103439.2 i/s - 7.02x  slower

                        flt_em100
              master:    651446.3 i/s
    bigdecimal 3.0.0:     79675.3 i/s - 8.18x  slower

```

https://github.com/ruby/bigdecimal/commit/5bdaedd530
https://github.com/ruby/bigdecimal/commit/9bfff57f90
https://github.com/ruby/bigdecimal/commit/d071a0abbb