Redmine

I confirmed that subsequent renderings within the same request become faster with code like the following.

require 'test_helper'
require 'benchmark/ips'

class ViewPerformanceTest < ActionDispatch::IntegrationTest
  def setup
    @controller = ApplicationController.new
    @controller.request = ActionDispatch::TestRequest.create
    @view_context = @controller.view_context
  end

  def test_view_benchmarks
    puts "\n--- Benchmarking Render Methods ---" 

    Benchmark.ips do |x|
      x.report('Helper (Cold Start)') do
        controller = ApplicationController.new
        controller.request = ActionDispatch::TestRequest.create
        view_context = controller.view_context
        view_context.wikitoolbar(preview_url: "/users/1"){'<textarea></textarea>'}
      end

      # Execute it once beforehand to memoize it.
      @view_context.wikitoolbar(preview_url: "/users/1"){'<textarea></textarea>'}

      x.report("Helper (Memoized)") do
        @view_context.wikitoolbar(preview_url: "/users/1"){'<textarea></textarea>'}
      end

      x.compare!
    end
  end
end

--- Benchmarking Render Methods ---
ruby 3.4.7 (2025-10-08 revision 7a5688e2a2) +PRISM [x86_64-linux]
Warming up --------------------------------------
 Helper (Cold Start)    40.000 i/100ms
   Helper (Memoized)   439.000 i/100ms
Calculating -------------------------------------
 Helper (Cold Start)    401.374 (±12.7%) i/s    (2.49 ms/i) -      2.000k in   5.073074s
   Helper (Memoized)      5.138k (±11.7%) i/s  (194.61 μs/i) -     25.462k in   5.033269s

Comparison:
   Helper (Memoized):     5138.4 i/s
 Helper (Cold Start):      401.4 i/s - 12.80x  slower