From 6e1d498ac7cd6fcd18352a22d8a3e3ed19df9c6b Mon Sep 17 00:00:00 2001 From: mrkn Date: Sun, 6 Jan 2019 00:46:36 +0000 Subject: [PATCH] range.c: optimize rb_range_last for int renage This change improves the performance of Range#last method for a range of integer. This optimization directly computes only required values only in a range instead of converting all values in the range to an array. The optimized implementation is 129-16.7k times faster than the previous one in the benchmark result given below. === Benchmark Result === ``` $ make benchmark ITEM=range_last COMPARE_RUBY=/Users/mrkn/.rbenv/versions/2.6.0/bin/ruby generating known_errors.inc known_errors.inc unchanged /Users/mrkn/src/github.com/ruby/ruby/revision.h unchanged /Users/mrkn/.rbenv/shims/ruby --disable=gems -rrubygems -I/Users/mrkn/src/github.com/ruby/ruby/benchmark/lib /Users/mrkn/src/github.com/ruby/ruby/benchmark/benchmark-driver/exe/benchmark-driver \ --executables="compare-ruby::/Users/mrkn/.rbenv/versions/2.6.0/bin/ruby -I.ext/common --disable-gem" \ --executables="built-ruby::./miniruby -I/Users/mrkn/src/github.com/ruby/ruby/lib -I. -I.ext/common -r/Users/mrkn/src/github.com/ruby/ruby/prelude --disable-gem" \ $(find /Users/mrkn/src/github.com/ruby/ruby/benchmark -maxdepth 1 -name '*range_last*.yml' -o -name '*range_last*.rb' | sort) Warming up -------------------------------------- (1..1_000_000).last(100) 35.600 i/s - 36.000 times in 1.011239s (28.09ms/i) (1..1_000_000).last(1000) 36.204 i/s - 39.000 times in 1.077240s (27.62ms/i) (1..1_000_000).last(10000) 36.470 i/s - 39.000 times in 1.069386s (27.42ms/i) Calculating ------------------------------------- compare-ruby built-ruby (1..1_000_000).last(100) 36.477 609.196k i/s - 106.000 times in 2.905950s 0.000174s (1..1_000_000).last(1000) 35.936 50.350k i/s - 108.000 times in 3.005321s 0.002145s (1..1_000_000).last(10000) 35.641 4.602k i/s - 109.000 times in 3.058233s 0.023685s Comparison: (1..1_000_000).last(100) built-ruby: 609195.7 i/s compare-ruby: 36.5 i/s - 16700.87x slower (1..1_000_000).last(1000) built-ruby: 50349.7 i/s compare-ruby: 35.9 i/s - 1401.08x slower (1..1_000_000).last(10000) built-ruby: 4602.1 i/s compare-ruby: 35.6 i/s - 129.12x slower ``` git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66734 b2dd03c8-39d4-4d8f-98ff-823fe69b080e --- range.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) diff --git a/range.c b/range.c index ac9affd872..77b1d7b25d 100644 --- a/range.c +++ b/range.c @@ -11,6 +11,7 @@ #include "internal.h" #include "id.h" +#include #ifdef HAVE_FLOAT_H #include @@ -1005,6 +1006,58 @@ range_first(int argc, VALUE *argv, VALUE range) return ary[1]; } +static VALUE +rb_int_range_last(int argc, VALUE *argv, VALUE range) +{ + static const VALUE ONE = INT2FIX(1); + + VALUE b, e, len_1, len, nv, ary; + int x; + long n; + + assert(argc > 0); + + b = RANGE_BEG(range); + e = RANGE_END(range); + assert(RB_INTEGER_TYPE_P(b) && RB_INTEGER_TYPE_P(e)); + + x = EXCL(range); + + len_1 = rb_int_minus(e, b); + if (FIXNUM_ZERO_P(len_1) || rb_num_negative_p(len_1)) { + return rb_ary_new_capa(0); + } + + if (x) { + e = rb_int_minus(e, ONE); + len = len_1; + } + else { + len = rb_int_plus(len_1, ONE); + } + + rb_scan_args(argc, argv, "1", &nv); + n = NUM2LONG(nv); + if (n < 0) { + rb_raise(rb_eArgError, "negative array size"); + } + + nv = LONG2NUM(n); + if (RTEST(rb_int_gt(nv, len))) { + nv = len; + n = NUM2LONG(nv); + } + + ary = rb_ary_new_capa(n); + b = rb_int_minus(e, nv); + while (n) { + b = rb_int_plus(b, ONE); + rb_ary_push(ary, b); + --n; + } + + return ary; +} /* * call-seq: @@ -1026,10 +1079,18 @@ range_first(int argc, VALUE *argv, VALUE range) static VALUE range_last(int argc, VALUE *argv, VALUE range) { + VALUE b, e; + if (NIL_P(RANGE_END(range))) { rb_raise(rb_eRangeError, "cannot get the last element of endless range"); } if (argc == 0) return RANGE_END(range); + + b = RANGE_BEG(range); + e = RANGE_END(range); + if (RB_INTEGER_TYPE_P(b) && RB_INTEGER_TYPE_P(e)) { + return rb_int_range_last(argc, argv, range); + } return rb_ary_last(argc, argv, rb_Array(range)); }