Ruby

Applied in changeset trunk|r58867.

Improve performance in where push the element into non shared Array object

• array.c (ary_ensure_room_for_push): use rb_ary_modify_check() instead of
  rb_ary_modify() to check whether the object can be modified for non shared
  Array object. rb_ary_modify() has the codes for shared Array object too.
  In here, it has condition branch for shared / non shared Array object and
  it can use rb_ary_modify_check() which is smaller function than
  rb_ary_modify() for non shared object.

  rb_ary_modify_check() will be expand as inline function.
  If it will compile with GCC, Array#<< will be faster around 8%.

  [ruby-core:81082] [Bug #13553] [Fix GH-1609]

Clang 802.0.42¶

Before¶

 Array#<< 9.353M (± 1.7%) i/s - 46.787M in 5.004123s Array#push 7.702M (± 1.1%) i/s - 38.577M in 5.009338s Array#values_at 6.133M (± 1.9%) i/s - 30.699M in 5.007772s 

After¶

 Array#<< 9.458M (± 2.0%) i/s - 47.357M in 5.009069s Array#push 7.921M (± 1.8%) i/s - 39.665M in 5.009151s Array#values_at 6.377M (± 2.3%) i/s - 31.881M in 5.001888s 

Result¶

Array#<< -> 1.2% faster
Array#push -> 2.8% faster
Array#values_at -> 3.9% faster

GCC 7.1.0¶

Before¶

 Array#<< 10.497M (± 1.1%) i/s - 52.665M in 5.017601s Array#push 8.527M (± 1.6%) i/s - 42.777M in 5.018003s Array#values_at 7.621M (± 1.7%) i/s - 38.152M in 5.007910s 

After¶

 Array#<< 11.403M (± 1.3%) i/s - 57.028M in 5.001849s Array#push 8.924M (± 1.3%) i/s - 44.609M in 4.999940s Array#values_at 8.291M (± 1.4%) i/s - 41.487M in 5.004727s 

Result¶

Array#<< -> 8.3% faster
Array#push -> 4.3% faster
Array#values_at -> 8.7% faster

Test code¶

require 'benchmark/ips'

Benchmark.ips do |x|

x.report "Array#<<" do |i|
i.times { [1,2] << 3 }
end

x.report "Array#push" do |i|
i.times { [1,2].push(3) }
end

x.report "Array#values_at" do |i|
ary = [1, 2, 3, 4, 5]
i.times { ary.values_at(0, 2, 4) }
end

end