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Feature #16635
closedReduce allocation of begin-less/end-less range with Integer literal
Status:
Closed
Assignee:
-
Target version:
-
Description
The patch is here. https://github.com/ruby/ruby/pull/2910
Currently Ruby optimizes Integer only Range with reducing Range allocation.
1..2
returns the same object.
For example:
$ ruby -e 'def a() 1..2 end; p a.object_id == a.object_id'
true
But it does not optimize begin-less/end-less ranges.
For example:
$ ruby -e 'def a() ..2 end; p a.object_id == a.object_id'
false
$ ruby -e 'def a() 1.. end; p a.object_id == a.object_id'
false
This patch applies the same optimization to begin-less/end-less ranges.
I think it will be helpful when we replace 1..-1
with ..-1
for String or Array slicing. Like str[1..-1]
.
We can rewrite str[1..-1]
to str[1..]
with keeping the speed with this patch.
Benchmark¶
It uses benchmark-driver gem.
# bench.yaml
prelude: |
def endless
1..
end
def beginless
..1
end
def endless_substr(str)
str[1..]
end
benchmark:
endless: endless
beginless: beginless
endless_substr: "endless_substr('foo')"
$ benchmark-driver test.yaml --rbenv 'patched;trunk'
Warming up --------------------------------------
endless 45.948M i/s - 46.076M times in 1.002782s (21.76ns/i, 26clocks/i)
beginless 49.986M i/s - 50.237M times in 1.005037s (20.01ns/i, 24clocks/i)
endless_substr 8.067M i/s - 8.187M times in 1.014936s (123.96ns/i, 148clocks/i)
Calculating -------------------------------------
patched trunk
endless 115.679M 21.500M i/s - 137.843M times in 1.191597s 6.411398s
beginless 112.599M 22.060M i/s - 149.957M times in 1.331778s 6.797768s
endless_substr 8.888M 6.760M i/s - 24.201M times in 2.722995s 3.580038s
Comparison:
endless
patched: 115679391.9 i/s
trunk: 21499711.2 i/s - 5.38x slower
beginless
patched: 112598731.5 i/s
trunk: 22059673.0 i/s - 5.10x slower
endless_substr
patched: 8887513.1 i/s
trunk: 6759886.2 i/s - 1.31x slower
trunk
is the HEAD of Ruby, and patched
is trunk
with this patch.
$ RBENV_VERSION=trunk ruby -v
ruby 2.8.0dev (2020-02-15T12:52:03Z master 961630126b) [x86_64-linux]
$ RBENV_VERSION=patched ruby -v
ruby 2.8.0dev (2020-02-15T12:52:03Z origin/master 961630126b) [x86_64-linux]
Updated by mame (Yusuke Endoh) about 4 years ago
- Tracker changed from Bug to Feature
- ruby -v deleted (
ruby 2.8.0dev (2020-02-15T12:52:03Z master 961630126b) [x86_64-linux]) - Backport deleted (
2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN)
Looks good. I will merge after it passes the CIs. Thanks.
Updated by k0kubun (Takashi Kokubun) about 4 years ago
- Status changed from Open to Closed
Merged in 527829423088f09cf2f708be12bb4337d640dc69
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