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author | nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2017-10-21 23:21:05 +0000 |
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committer | nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2017-10-21 23:21:05 +0000 |
commit | 80c50308f9db813e999367ec5d116e2d2be9f840 (patch) | |
tree | 85b28d288cf288c7c2ac7e6329616c6d3bf9778b /ext | |
parent | d808918583d406d93c9007cf14a9f39af7e4b83e (diff) | |
download | ruby-80c50308f9db813e999367ec5d116e2d2be9f840.tar.gz |
Improve performance of string interpolation
This patch will add pre-allocation in string interpolation.
By this, unecessary capacity resizing is avoided.
For small strings, optimized `rb_str_resurrect` operation is
faster, so pre-allocation is done only when concatenated strings
are large. `MIN_PRE_ALLOC_SIZE` was decided by experimenting with
local machine (x86_64-apple-darwin 16.5.0, Apple LLVM version
8.1.0 (clang - 802.0.42)).
String interpolation will be faster around 72% when large string is created.
* Before
```
Calculating -------------------------------------
Large string interpolation
1.276M (± 5.9%) i/s - 6.358M in 5.002022s
Small string interpolation
5.156M (± 5.5%) i/s - 25.728M in 5.005731s
```
* After
```
Calculating -------------------------------------
Large string interpolation
2.201M (± 5.8%) i/s - 11.063M in 5.043724s
Small string interpolation
5.192M (± 5.7%) i/s - 25.971M in 5.020516s
```
* Test code
```ruby
require 'benchmark/ips'
Benchmark.ips do |x|
x.report "Large string interpolation" do |t|
a = "Hellooooooooooooooooooooooooooooooooooooooooooooooooooo"
b = "Wooooooooooooooooooooooooooooooooooooooooooooooooooorld"
t.times do
"#{a}, #{b}!"
end
end
x.report "Small string interpolation" do |t|
a = "Hello"
b = "World"
t.times do
"#{a}, #{b}!"
end
end
end
```
[Fix GH-1626]
From: Nao Minami <south37777@gmail.com>
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60320 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'ext')
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