From: "k0kubun (Takashi Kokubun) via ruby-core" <ruby-core@ml.ruby-lang.org>
To: ruby-core@ml.ruby-lang.org
Cc: "k0kubun (Takashi Kokubun)" <noreply@ruby-lang.org>
Subject: [ruby-core:119002] [Ruby master Bug#20641] `lib/bundled_gems.rb` makes `Kernel.require` over 100x slower
Date: Mon, 02 Sep 2024 09:39:12 +0000 (UTC) [thread overview]
Message-ID: <redmine.journal-109577.20240902093912.7941@ruby-lang.org> (raw)
In-Reply-To: <redmine.issue-20641.20240719120317.7941@ruby-lang.org>
Issue #20641 has been updated by k0kubun (Takashi Kokubun).
Backport changed from 3.1: DONTNEED, 3.2: DONTNEED, 3.3: REQUIRED to 3.1: DONTNEED, 3.2: DONTNEED, 3.3: DONE
ruby_3_3 commit:4667f8ec10269b0b5deca459f098abbdf3bae4ec.
----------------------------------------
Bug #20641: `lib/bundled_gems.rb` makes `Kernel.require` over 100x slower
https://bugs.ruby-lang.org/issues/20641#change-109577
* Author: byroot (Jean Boussier)
* Status: Closed
* Backport: 3.1: DONTNEED, 3.2: DONTNEED, 3.3: DONE
----------------------------------------
I just discovered this while profiling Active Record's test suite, and I noticed 40% of the runtime was in `$LOAD_PATH.resolve_feature_path`, so much I thought it was a profiler bug.
But it turns out it's real. Various APIs do call `require` late, for instance Psych calls `require 'date'` every single time it parses a date: https://github.com/ruby/psych/blob/be0ba74e5613c20f213403e15914d24944c2652d/lib/psych/scalar_scanner.rb#L64
I've put together a quick benchmark:
```ruby
# frozen_string_literal: true
require "bundler/inline"
gemfile(true) do
source "https://rubygems.org"
gem "benchmark-ips"
end
Benchmark.ips do |x|
x.report(RUBY_VERSION) { require "erb" }
x.save! "/tmp/require.bench"
x.compare!
end
```
And the difference is massive:
```
Calculating -------------------------------------
3.2.2 6.450M (± 1.2%) i/s - 32.822M in 5.089538s
Comparison:
3.2.2: 6449899.4 i/s
3.3.3: 46996.8 i/s - 137.24x slower
```
And that's with a small `$LOAD_PATH`, the bigger the application, the worse it is, if I add:
```ruby
100.times do |i|
$LOAD_PATH.unshift("/tmp/empty-#{i}")
end
```
```
Calculating -------------------------------------
3.3.3 6.198k (± 6.1%) i/s - 30.968k in 5.018955s
Comparison:
3.2.2: 3380939.6 i/s
3.3.3: 6198.4 i/s - 545.46x slower
```
I'm looking at a way to speed this up, but this is big enough that I believe we should backport the fix.
cc @hsbt
--
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prev parent reply other threads:[~2024-09-02 9:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-19 12:03 [ruby-core:118637] " byroot (Jean Boussier) via ruby-core
2024-07-19 15:08 ` [ruby-core:118638] " byroot (Jean Boussier) via ruby-core
2024-09-02 9:39 ` k0kubun (Takashi Kokubun) via ruby-core [this message]
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