Improve memory usage in Bundler::Settings, and thus improve boot time #6884

technicalpickles · 2023-08-16T19:33:31Z

What was the end-user or developer problem that led to this PR?

I was running memory_profiler on our Rails app boot-time, and saw some opportunities.

What is your fix for the problem, implemented in this PR?

I used this code to scope memory allocations in our rails app to just bundler:

require 'memory_profiler'

MemoryProfiler.report(allow_files: 'bundler/settings.rb') do
  require_relative 'config/environment'
end.pretty_print

And then compared it with these changes by adding adding calling it with ruby -Ipath/to/checkout/rubygems/bundler/lib.

Memory

Before:

Total allocated: 4883872 bytes (65211 objects)
Total retained:  22644 bytes (226 objects)


allocated memory by file
-----------------------------------
   4883872  /Users/josh.nichols/.rbenv/versions/3.2.2/lib/ruby/gems/3.2.0/gems/bundler-2.4.18/lib/bundler/settings.rb

allocated objects by file
-----------------------------------
     28606  /Users/josh.nichols/workspace/rubygems/bundler/lib/bundler/settings.rb

retained memory by file
-----------------------------------
     21333  /Users/josh.nichols/workspace/rubygems/bundler/lib/bundler/settings.rb

retained objects by file
-----------------------------------
       226  /Users/josh.nichols/workspace/rubygems/bundler/lib/bundler/settings.rb

After:

Total allocated: 2326771 bytes (28606 objects)
Total retained:  20207 bytes (221 objects)

allocated memory by file
-----------------------------------
   2326771  /Users/josh.nichols/workspace/rubygems/bundler/lib/bundler/settings.rb

allocated objects by file
-----------------------------------
     28606  /Users/josh.nichols/workspace/rubygems/bundler/lib/bundler/settings.rb


retained memory by file
-----------------------------------
     20207  /Users/josh.nichols/workspace/rubygems/bundler/lib/bundler/settings.rb

retained objects by file
-----------------------------------
       221  /Users/josh.nichols/workspace/rubygems/bundler/lib/bundler/settings.rb

Runtime

For runtime, I with the same file above, but without the memory_profiling:

require_relative 'config/environment'

I used hyperfine to compare before/after: hyperfine "ruby boot-time-benchmark.rb" "ruby -I/Users/josh.nichols/workspace/rubygems/bundler/lib boot-time-benchmark.rb":

Summary

This reduces the amount of memory allocated during Rails startup in our app by 52%, from 4_883_872 bytes to 2_326_771 bytes.

It also reduces startup time by 6%, from 8.807s to 8.256s.

Make sure the following tasks are checked

Describe the problem / feature
Write tests for features and bug fixes
Write code to solve the problem
Make sure you follow the current code style and write meaningful commit messages without tags

…ng another hash. `String#start_with?` is faster than regex that is bound to the start of a string.

… can use bang methods to avoid allocating new copies

… saves allocating 2 arrays

The individual keys are also new, so we can use ! methods on each individual one as well.

…iple times

…, which is not used

Use .prepend to avoid allocating a new string.

indirect · 2023-08-16T19:44:12Z

Nice! A boon for the massively-environmented users everywhere 😂

technicalpickles · 2023-08-16T20:08:02Z

I think I got over-ambitious with this PR, and now I'm getting tons of failures that aren't super obvious where to begin (ie expected some big string, but got empty string) so will break some of these out.

bundler/lib/bundler/settings.rb

…e that

technicalpickles · 2023-08-19T16:24:29Z

@martinemde pushed up those changes!

deivid-rodriguez · 2023-08-25T09:18:35Z

Hei, I didn't fin time to chime in here, but THIS IS SO AWESOME! Thank you so much!

I previously identified and improved this method over in rubygems#6884 but while reviewing another memory_profiler profile, I realized another gain we can eek out. This method keeps comes up in part because `configs` is allocating a new Hash every time. My last change took advantage of that by using `map!` on it. `configs` is called quite often, including in this `[]` method, so there's a benefit to memoizing it. Back in `[]`, logically we are trying to find the first Hash in `configs` that has a value for the given key. Currently, we end up `map` and `compact` to just get that value. Instead, we can use a loop over `configs`, and break when we find the value for the key.

…e and memory usage I previously identified and improved this method over in rubygems/rubygems#6884 but while reviewing another memory_profiler profile, I realized another gain we can eek out. This method keeps comes up in part because `configs` is allocating a new Hash every time. My last change took advantage of that by using `map!` on it. `configs` is called quite often, including in this `[]` method, so there's a benefit to memoizing it. Back in `[]`, logically we are trying to find the first Hash in `configs` that has a value for the given key. Currently, we end up `map` and `compact` to just get that value. Instead, we can use a loop over `configs`, and break when we find the value for the key. rubygems/rubygems@b913cfc87b

Improve memory usage in Bundler::Settings, and thus improve boot time (cherry picked from commit 06231fd)

technicalpickles added 10 commits August 16, 2023 14:57

ENV.to_h returns a new hash, so we can select! it to avoid allocati…

9b2006e

…ng another hash. `String#start_with?` is faster than regex that is bound to the start of a string.

config is a new Hash, and config.values is a new Array. that means we…

8bc13fa

… can use bang methods to avoid allocating new copies

Use Array#union to join these, instead of with | multiple times. This…

48c03b3

… saves allocating 2 arrays

Use ! methods on the array, since it is brand new.

f2e912b

The individual keys are also new, so we can use ! methods on each individual one as well.

String#start_with? is faster than regex with beginning boundaries

d7cde68

name is often a symbol, so only to_s once to avoid allocating it mult…

8eac49c

…iple times

Use .to_s once in the beginning to save allocations if it's a symbol.

f8167db

Use value.match? only on Strings, which avoids allocating a matchdata…

cbf9ac9

…, which is not used

call key.to_s once instead of multiple times to save when it's a symbol

535feb8

Use ! methods once we have a new copy of the string.

2ac35a6

Use .prepend to avoid allocating a new string.

segiddins reviewed Aug 17, 2023

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martinemde reviewed Aug 17, 2023

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martinemde reviewed Aug 17, 2023

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martinemde and others added 3 commits August 18, 2023 09:31

Don't rely on globals when not matching regexp for "local."

e79ccda

handle removing BUNDLE_, since using start_with? would still includ…

235d9b3

…e that

use a one-liner

4674588

fix lint

75c0f27

segiddins approved these changes Aug 19, 2023

View reviewed changes

indirect merged commit 06231fd into rubygems:master Aug 20, 2023
92 checks passed

technicalpickles deleted the settings-memory branch August 21, 2023 16:30

deivid-rodriguez added the bundler: performance label Aug 25, 2023

technicalpickles mentioned this pull request Aug 29, 2023

(Further) Improve Bundler::Settings#[] performance and memory usage #6923

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deivid-rodriguez pushed a commit that referenced this pull request Sep 21, 2023

Merge pull request #6884 from technicalpickles/settings-memory

04c4af3

Improve memory usage in Bundler::Settings, and thus improve boot time (cherry picked from commit 06231fd)

deivid-rodriguez pushed a commit that referenced this pull request Sep 21, 2023

Merge pull request #6884 from technicalpickles/settings-memory

f160d55

Improve memory usage in Bundler::Settings, and thus improve boot time (cherry picked from commit 06231fd)

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Improve memory usage in Bundler::Settings, and thus improve boot time #6884

Improve memory usage in Bundler::Settings, and thus improve boot time #6884

technicalpickles commented Aug 16, 2023 •

edited

indirect commented Aug 16, 2023

technicalpickles commented Aug 16, 2023

technicalpickles commented Aug 19, 2023

deivid-rodriguez commented Aug 25, 2023

Improve memory usage in Bundler::Settings, and thus improve boot time #6884

Improve memory usage in Bundler::Settings, and thus improve boot time #6884

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technicalpickles commented Aug 16, 2023 • edited

What was the end-user or developer problem that led to this PR?

What is your fix for the problem, implemented in this PR?

Memory

Runtime

Summary

Make sure the following tasks are checked

indirect commented Aug 16, 2023

technicalpickles commented Aug 16, 2023

technicalpickles commented Aug 19, 2023

deivid-rodriguez commented Aug 25, 2023

technicalpickles commented Aug 16, 2023 •

edited