From bbac8958097b644ddad4a9762d4b8fd5939da566 Mon Sep 17 00:00:00 2001
From: Adam Doppelt <amd@gurge.com>
Date: Tue, 19 Aug 2025 22:01:57 -0700
Subject: [PATCH 1/9] wip

---
 lib/image_optim.rb                      | 27 ++++++++++
 lib/image_optim/benchmark.rb            | 21 ++++++++
 lib/image_optim/runner.rb               | 64 ++++++++++++++++++++++--
 lib/image_optim/runner/option_parser.rb |  5 ++
 lib/image_optim/table.rb                | 66 +++++++++++++++++++++++++
 5 files changed, 178 insertions(+), 5 deletions(-)
 create mode 100644 lib/image_optim/benchmark.rb
 create mode 100644 lib/image_optim/table.rb

diff --git a/lib/image_optim.rb b/lib/image_optim.rb
index 184d170e..49a558f7 100644
--- a/lib/image_optim.rb
+++ b/lib/image_optim.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require 'image_optim/benchmark'
 require 'image_optim/bin_resolver'
 require 'image_optim/cache'
 require 'image_optim/config'
@@ -8,6 +9,7 @@
 require 'image_optim/image_meta'
 require 'image_optim/optimized_path'
 require 'image_optim/path'
+require 'image_optim/table'
 require 'image_optim/timer'
 require 'image_optim/worker'
 require 'in_threads'
@@ -162,6 +164,27 @@ def optimize_image_data(original_data)
     end
   end
 
+  def benchmark_image(original)
+    src = Path.convert(original)
+    return unless (workers = workers_for_image(src))
+
+    timer = timeout && Timer.new(timeout)
+    workers.map do |worker|
+      start = ElapsedTime.now
+      dst = src.temp_path
+      begin
+        begin
+          worker.optimize(src, dst, timeout: timer)
+        rescue Errors::TimeoutExceeded
+          # nop
+        end
+        Benchmark.new(src: src, dst: dst, elapsed: (ElapsedTime.now - start), worker: worker)
+      ensure
+        dst.unlink
+      end
+    end
+  end
+
   # Optimize multiple images
   # if block given yields path and result for each image and returns array of
   # yield results
@@ -186,6 +209,10 @@ def optimize_images_data(datas, &block)
     run_method_for(datas, :optimize_image_data, &block)
   end
 
+  def benchmark_images(paths, &block)
+    run_method_for(paths, :benchmark_image, &block)
+  end
+
   class << self
     # Optimization methods with default options
     def method_missing(method, *args, &block)
diff --git a/lib/image_optim/benchmark.rb b/lib/image_optim/benchmark.rb
new file mode 100644
index 00000000..968366a4
--- /dev/null
+++ b/lib/image_optim/benchmark.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+class ImageOptim
+  # Benchmark result for one worker+src
+  class Benchmark
+    attr_reader :bytes, :elapsed, :worker
+
+    def initialize(src:, dst:, elapsed:, worker:)
+      @bytes = bytes_saved(src, dst)
+      @elapsed = elapsed
+      @worker = worker.class.bin_sym.to_s
+    end
+
+    def bytes_saved(src, dst)
+      src, dst = src.size, dst.size
+      return 0 if dst == 0 # failure
+      return 0 if dst > src # the file got bigger
+      src - dst
+    end
+  end
+end
diff --git a/lib/image_optim/runner.rb b/lib/image_optim/runner.rb
index 94a8dba5..d0faf83e 100644
--- a/lib/image_optim/runner.rb
+++ b/lib/image_optim/runner.rb
@@ -45,10 +45,51 @@ def size_percent(size_a, size_b)
       end
     end
 
+    # files, elapsed, kb saved, kb/s
+    class BenchmarkResults
+      def initialize
+        @all = []
+      end
+
+      def add(_original, rows)
+        @all.concat(rows)
+      end
+
+      def print
+        if @all.empty?
+          puts 'nothing to report'
+          return
+        end
+
+        # group by worker
+        report = @all.group_by(&:worker).map do |name, results|
+          kb = (results.sum(&:bytes) / 1024.0)
+          elapsed = results.sum(&:elapsed)
+          {
+            'name' => name,
+            'files' => results.length,
+            'elapsed' => elapsed,
+            'kb saved' => kb,
+            'kb/s' => (kb / elapsed),
+          }
+        end
+
+        # sort
+        report = report.sort_by do |row|
+          [-row['kb/s'], row['name']]
+        end
+
+        # output
+        puts "\nBENCHMARK RESULTS\n\n"
+        puts Table.new(report)
+      end
+    end
+
     def initialize(options)
       options = HashHelpers.deep_symbolise_keys(options)
       @recursive = options.delete(:recursive)
       @progress = options.delete(:show_progress) != false
+      @benchmark = options.delete(:benchmark)
       @exclude_dir_globs, @exclude_file_globs = %w[dir file].map do |type|
         glob = options.delete(:"exclude_#{type}_glob") || '.*'
         GlobHelpers.expand_braces(glob)
@@ -59,13 +100,21 @@ def initialize(options)
     def run!(args) # rubocop:disable Naming/PredicateMethod
       to_optimize = find_to_optimize(args)
       unless to_optimize.empty?
-        results = Results.new
+        if @benchmark
+          benchmark_results = BenchmarkResults.new
+          benchmark_images(to_optimize).each do |original, bm|
+            benchmark_results.add(original, bm)
+          end
+          benchmark_results.print
+        else
+          results = Results.new
 
-        optimize_images!(to_optimize).each do |original, optimized|
-          results.add(original, optimized)
-        end
+          optimize_images!(to_optimize).each do |original, optimized|
+            results.add(original, optimized)
+          end
 
-        results.print
+          results.print
+        end
       end
 
       !@warnings
@@ -73,6 +122,11 @@ def run!(args) # rubocop:disable Naming/PredicateMethod
 
   private
 
+    def benchmark_images(to_optimize, &block)
+      to_optimize = to_optimize.with_progress('benchmarking') if @progress
+      @image_optim.benchmark_images(to_optimize, &block)
+    end
+
     def optimize_images!(to_optimize, &block)
       to_optimize = to_optimize.with_progress('optimizing') if @progress
       @image_optim.optimize_images!(to_optimize, &block)
diff --git a/lib/image_optim/runner/option_parser.rb b/lib/image_optim/runner/option_parser.rb
index 3af60c52..f051d98e 100644
--- a/lib/image_optim/runner/option_parser.rb
+++ b/lib/image_optim/runner/option_parser.rb
@@ -153,6 +153,11 @@ def wrap_regex(width)
     options[:pack] = pack
   end
 
+  op.separator nil
+  op.on('--benchmark', 'Run in benchmark mode, to compare tools without modifying images') do
+    options[:benchmark] = true
+  end
+
   op.separator nil
   op.separator '  Caching:'
 
diff --git a/lib/image_optim/table.rb b/lib/image_optim/table.rb
new file mode 100644
index 00000000..9cb8f1d2
--- /dev/null
+++ b/lib/image_optim/table.rb
@@ -0,0 +1,66 @@
+# frozen_string_literal: true
+
+class ImageOptim
+  # Handy class for pretty printing a table in the terminal. This is very simple, switch to Terminal
+  # Table, Table Tennis or similar if we need more.
+  class Table
+    attr_reader :rows
+
+    def initialize(rows)
+      @rows = rows
+    end
+
+    def to_s
+      lines = []
+      lines << render_row(columns)
+      lines << render_sep
+      rows.each do |row|
+        lines << render_row(row.values)
+      end
+      lines.join("\n")
+    end
+
+  protected
+
+    # array of column names
+    def columns
+      @columns ||= rows.first.keys
+    end
+
+    # should columns be justified left or right?
+    def justs
+      @justs ||= columns.map do |col|
+        rows.first[col].is_a?(Numeric) ? :rjust : :ljust
+      end
+    end
+
+    # max width of each column
+    def widths
+      @widths ||= columns.map do |col|
+        values = rows.map{ |row| fmt(row[col]) }
+        ([col] + values).map(&:length).max
+      end
+    end
+
+    # render an array of row values
+    def render_row(values)
+      values.map.with_index do |value, ii|
+        fmt(value).send(justs[ii], widths[ii])
+      end.join('  ')
+    end
+
+    # render a separator line
+    def render_sep
+      render_row(widths.map{ |width| '-' * width })
+    end
+
+    # format one cell value
+    def fmt(value)
+      if value.is_a?(Float)
+        format('%0.3f', value)
+      else
+        value.to_s
+      end
+    end
+  end
+end

From eb6e931eb54d8504a4427dbbfd47258942e8a8a1 Mon Sep 17 00:00:00 2001
From: Adam Doppelt <amd@gurge.com>
Date: Wed, 20 Aug 2025 09:59:14 -0700
Subject: [PATCH 2/9] ruby 1.9 fix

---
 lib/image_optim/benchmark.rb | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/image_optim/benchmark.rb b/lib/image_optim/benchmark.rb
index 968366a4..143b6d35 100644
--- a/lib/image_optim/benchmark.rb
+++ b/lib/image_optim/benchmark.rb
@@ -5,7 +5,7 @@ class ImageOptim
   class Benchmark
     attr_reader :bytes, :elapsed, :worker
 
-    def initialize(src:, dst:, elapsed:, worker:)
+    def initialize(src: nil, dst: nil, elapsed: nil, worker: nil)
       @bytes = bytes_saved(src, dst)
       @elapsed = elapsed
       @worker = worker.class.bin_sym.to_s
@@ -15,6 +15,7 @@ def bytes_saved(src, dst)
       src, dst = src.size, dst.size
       return 0 if dst == 0 # failure
       return 0 if dst > src # the file got bigger
+
       src - dst
     end
   end

From f631a4c46a17f933a02107c931f61dafb811fd25 Mon Sep 17 00:00:00 2001
From: Adam Doppelt <amd@gurge.com>
Date: Wed, 20 Aug 2025 10:01:55 -0700
Subject: [PATCH 3/9] ruby 1.9 fix

---
 lib/image_optim.rb           | 2 +-
 lib/image_optim/benchmark.rb | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/image_optim.rb b/lib/image_optim.rb
index 49a558f7..69920f3a 100644
--- a/lib/image_optim.rb
+++ b/lib/image_optim.rb
@@ -178,7 +178,7 @@ def benchmark_image(original)
         rescue Errors::TimeoutExceeded
           # nop
         end
-        Benchmark.new(src: src, dst: dst, elapsed: (ElapsedTime.now - start), worker: worker)
+        Benchmark.new(src, dst, ElapsedTime.now - start, worker)
       ensure
         dst.unlink
       end
diff --git a/lib/image_optim/benchmark.rb b/lib/image_optim/benchmark.rb
index 143b6d35..8bd7266e 100644
--- a/lib/image_optim/benchmark.rb
+++ b/lib/image_optim/benchmark.rb
@@ -5,7 +5,7 @@ class ImageOptim
   class Benchmark
     attr_reader :bytes, :elapsed, :worker
 
-    def initialize(src: nil, dst: nil, elapsed: nil, worker: nil)
+    def initialize(src, dst, elapsed, worker)
       @bytes = bytes_saved(src, dst)
       @elapsed = elapsed
       @worker = worker.class.bin_sym.to_s

From b63e1dccc39ab3b08a86fca7952c33d053a68b65 Mon Sep 17 00:00:00 2001
From: Adam Doppelt <amd@gurge.com>
Date: Wed, 3 Sep 2025 08:56:31 -0700
Subject: [PATCH 4/9] PR feedback

---
 CHANGELOG.markdown           |  1 +
 README.markdown              | 21 +++++++++++++++++++++
 lib/image_optim.rb           |  9 ++-------
 lib/image_optim/benchmark.rb |  4 +++-
 lib/image_optim/config.rb    |  3 +++
 lib/image_optim/runner.rb    | 19 ++++++++++++++-----
 lib/image_optim/table.rb     | 14 ++++++--------
 spec/image_optim_spec.rb     | 14 ++++++++++++++
 8 files changed, 64 insertions(+), 21 deletions(-)

diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
index 507fbd0c..965a74d1 100644
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -3,6 +3,7 @@
 ## unreleased
 
 * Correct environment variable to specify `jpeg-recompress` location [@toy](https://github.com/toy)
+* Added --benchmark, to compare performance of each tool [#218]
 
 ## v0.31.4 (2024-11-19)
 
diff --git a/README.markdown b/README.markdown
index a6f46fbe..6edee407 100644
--- a/README.markdown
+++ b/README.markdown
@@ -301,6 +301,27 @@ optipng:
 
 `image_optim` uses standard ruby library for creating temporary files. Temporary directory can be changed using one of `TMPDIR`, `TMP` or `TEMP` environment variables.
 
+### Benchmark
+
+Run with `--benchmark` to compare the performance of each individual tool on your images:
+
+```
+$ image_optim --benchmark -r /tmp/corpus/
+
+benchmarking: 100.0% (elapsed: 3.9m)
+
+BENCHMARK RESULTS
+
+name      files  elapsed  kb saved     kb/s
+--------  -----  -------  --------  -------
+oxipng       50    8.906  1867.253  209.664
+pngquant     50    1.980   214.597  108.386
+pngcrush     50   22.529  1753.704   77.841
+optipng      50  142.940  1641.101   11.481
+advpng       50  137.753   962.549    6.987
+pngout       50  426.706   444.679    1.042
+```
+
 ## Options
 
 * `:nice` — Nice level, priority of all used tools with higher value meaning lower priority, in range `-20..19`, negative values can be set only if run by root user *(defaults to `10`)*
diff --git a/lib/image_optim.rb b/lib/image_optim.rb
index 69920f3a..3c98f2ff 100644
--- a/lib/image_optim.rb
+++ b/lib/image_optim.rb
@@ -168,17 +168,12 @@ def benchmark_image(original)
     src = Path.convert(original)
     return unless (workers = workers_for_image(src))
 
-    timer = timeout && Timer.new(timeout)
     workers.map do |worker|
       start = ElapsedTime.now
       dst = src.temp_path
       begin
-        begin
-          worker.optimize(src, dst, timeout: timer)
-        rescue Errors::TimeoutExceeded
-          # nop
-        end
-        Benchmark.new(src, dst, ElapsedTime.now - start, worker)
+        worker.optimize(src, dst)
+        BenchmarkResult.new(src, dst, ElapsedTime.now - start, worker)
       ensure
         dst.unlink
       end
diff --git a/lib/image_optim/benchmark.rb b/lib/image_optim/benchmark.rb
index 8bd7266e..81041bfb 100644
--- a/lib/image_optim/benchmark.rb
+++ b/lib/image_optim/benchmark.rb
@@ -2,7 +2,7 @@
 
 class ImageOptim
   # Benchmark result for one worker+src
-  class Benchmark
+  class BenchmarkResult
     attr_reader :bytes, :elapsed, :worker
 
     def initialize(src, dst, elapsed, worker)
@@ -11,6 +11,8 @@ def initialize(src, dst, elapsed, worker)
       @worker = worker.class.bin_sym.to_s
     end
 
+  private
+
     def bytes_saved(src, dst)
       src, dst = src.size, dst.size
       return 0 if dst == 0 # failure
diff --git a/lib/image_optim/config.rb b/lib/image_optim/config.rb
index 9b27be09..048d16a8 100644
--- a/lib/image_optim/config.rb
+++ b/lib/image_optim/config.rb
@@ -117,6 +117,9 @@ def threads
 
       case threads
       when true, nil
+        # --benchmark defaults to one thread
+        return 1 if get!(:benchmark)
+
         processor_count
       when false
         1
diff --git a/lib/image_optim/runner.rb b/lib/image_optim/runner.rb
index d0faf83e..19e692cc 100644
--- a/lib/image_optim/runner.rb
+++ b/lib/image_optim/runner.rb
@@ -51,7 +51,7 @@ def initialize
         @all = []
       end
 
-      def add(_original, rows)
+      def add(rows)
         @all.concat(rows)
       end
 
@@ -81,7 +81,7 @@ def print
 
         # output
         puts "\nBENCHMARK RESULTS\n\n"
-        puts Table.new(report)
+        Table.new(report).write($stdout)
       end
     end
 
@@ -89,11 +89,20 @@ def initialize(options)
       options = HashHelpers.deep_symbolise_keys(options)
       @recursive = options.delete(:recursive)
       @progress = options.delete(:show_progress) != false
-      @benchmark = options.delete(:benchmark)
       @exclude_dir_globs, @exclude_file_globs = %w[dir file].map do |type|
         glob = options.delete(:"exclude_#{type}_glob") || '.*'
         GlobHelpers.expand_braces(glob)
       end
+
+      # --benchmark
+      @benchmark = options.delete(:benchmark)
+      if @benchmark
+        options[:threads] = 1 # for consistency
+        if options[:timeout]
+          warning '--benchmark ignores --timeout'
+        end
+      end
+
       @image_optim = ImageOptim.new(options)
     end
 
@@ -102,8 +111,8 @@ def run!(args) # rubocop:disable Naming/PredicateMethod
       unless to_optimize.empty?
         if @benchmark
           benchmark_results = BenchmarkResults.new
-          benchmark_images(to_optimize).each do |original, bm|
-            benchmark_results.add(original, bm)
+          benchmark_images(to_optimize).each do |_original, rows|
+            benchmark_results.add(rows)
           end
           benchmark_results.print
         else
diff --git a/lib/image_optim/table.rb b/lib/image_optim/table.rb
index 9cb8f1d2..ec458485 100644
--- a/lib/image_optim/table.rb
+++ b/lib/image_optim/table.rb
@@ -10,14 +10,12 @@ def initialize(rows)
       @rows = rows
     end
 
-    def to_s
-      lines = []
-      lines << render_row(columns)
-      lines << render_sep
+    def write(io)
+      io.puts render_row(columns)
+      io.puts render_sep
       rows.each do |row|
-        lines << render_row(row.values)
+        io.puts render_row(row.values)
       end
-      lines.join("\n")
     end
 
   protected
@@ -44,8 +42,8 @@ def widths
 
     # render an array of row values
     def render_row(values)
-      values.map.with_index do |value, ii|
-        fmt(value).send(justs[ii], widths[ii])
+      values.zip(justs, widths).map do |value, just, width|
+        fmt(value).send(just, width)
       end.join('  ')
     end
 
diff --git a/spec/image_optim_spec.rb b/spec/image_optim_spec.rb
index 6a651258..76d46586 100644
--- a/spec/image_optim_spec.rb
+++ b/spec/image_optim_spec.rb
@@ -269,6 +269,20 @@ def temp_copy(image)
     end
   end
 
+  describe 'benchmark_images' do
+    it 'does it' do
+      image_optim = ImageOptim.new
+      pairs = image_optim.benchmark_images(test_images)
+      test_images.zip(pairs).each do |original, (src, bm)|
+        expect(original).to equal(src)
+        expect(bm[0]).to be_a(ImageOptim::BenchmarkResult)
+        expect(bm[0].bytes).to be_a(Numeric)
+        expect(bm[0].elapsed).to be_a(Numeric)
+        expect(bm[0].worker).to be_a(String)
+      end
+    end
+  end
+
   %w[
     optimize_image
     optimize_image!

From 49ad630821f51b0f3838c16d6de7f49b192bc9e0 Mon Sep 17 00:00:00 2001
From: Adam Doppelt <amd@gurge.com>
Date: Wed, 3 Sep 2025 09:04:45 -0700
Subject: [PATCH 5/9] fix a rubocop warning

---
 lib/image_optim/runner.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/image_optim/runner.rb b/lib/image_optim/runner.rb
index 19e692cc..20e19132 100644
--- a/lib/image_optim/runner.rb
+++ b/lib/image_optim/runner.rb
@@ -111,7 +111,7 @@ def run!(args) # rubocop:disable Naming/PredicateMethod
       unless to_optimize.empty?
         if @benchmark
           benchmark_results = BenchmarkResults.new
-          benchmark_images(to_optimize).each do |_original, rows|
+          benchmark_images(to_optimize).each do |_original, rows| # rubocop:disable Style/HashEachMethods
             benchmark_results.add(rows)
           end
           benchmark_results.print

From c844f00bf64d111498e5d10769603768049773c9 Mon Sep 17 00:00:00 2001
From: Adam Doppelt <amd@gurge.com>
Date: Tue, 23 Sep 2025 18:42:35 -0700
Subject: [PATCH 6/9] PR feedback round 2

---
 CHANGELOG.markdown                                    | 2 +-
 README.markdown                                       | 4 +++-
 lib/image_optim.rb                                    | 2 +-
 lib/image_optim/{benchmark.rb => benchmark_result.rb} | 0
 lib/image_optim/config.rb                             | 3 ---
 lib/image_optim/runner.rb                             | 5 ++++-
 6 files changed, 9 insertions(+), 7 deletions(-)
 rename lib/image_optim/{benchmark.rb => benchmark_result.rb} (100%)

diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
index 965a74d1..95efa3d9 100644
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -3,7 +3,7 @@
 ## unreleased
 
 * Correct environment variable to specify `jpeg-recompress` location [@toy](https://github.com/toy)
-* Added --benchmark, to compare performance of each tool [#218]
+* Added --benchmark, to compare performance of each tool [#217](https://github.com/toy/image_optim/issues/217) [#218](https://github.com/toy/image_optim/pull/218) [@gurgeous](https://github.com/gurgeous)
 
 ## v0.31.4 (2024-11-19)
 
diff --git a/README.markdown b/README.markdown
index 6edee407..7cbfe9b6 100644
--- a/README.markdown
+++ b/README.markdown
@@ -305,9 +305,11 @@ optipng:
 
 Run with `--benchmark` to compare the performance of each individual tool on your images:
 
+```sh
+image_optim --benchmark -r /tmp/corpus/
 ```
-$ image_optim --benchmark -r /tmp/corpus/
 
+```
 benchmarking: 100.0% (elapsed: 3.9m)
 
 BENCHMARK RESULTS
diff --git a/lib/image_optim.rb b/lib/image_optim.rb
index 3c98f2ff..dcf0e33c 100644
--- a/lib/image_optim.rb
+++ b/lib/image_optim.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require 'image_optim/benchmark'
+require 'image_optim/benchmark_result'
 require 'image_optim/bin_resolver'
 require 'image_optim/cache'
 require 'image_optim/config'
diff --git a/lib/image_optim/benchmark.rb b/lib/image_optim/benchmark_result.rb
similarity index 100%
rename from lib/image_optim/benchmark.rb
rename to lib/image_optim/benchmark_result.rb
diff --git a/lib/image_optim/config.rb b/lib/image_optim/config.rb
index 048d16a8..9b27be09 100644
--- a/lib/image_optim/config.rb
+++ b/lib/image_optim/config.rb
@@ -117,9 +117,6 @@ def threads
 
       case threads
       when true, nil
-        # --benchmark defaults to one thread
-        return 1 if get!(:benchmark)
-
         processor_count
       when false
         1
diff --git a/lib/image_optim/runner.rb b/lib/image_optim/runner.rb
index 20e19132..02cee96e 100644
--- a/lib/image_optim/runner.rb
+++ b/lib/image_optim/runner.rb
@@ -97,7 +97,10 @@ def initialize(options)
       # --benchmark
       @benchmark = options.delete(:benchmark)
       if @benchmark
-        options[:threads] = 1 # for consistency
+        unless options[:threads].nil?
+          warning '--benchmark ignores --threads'
+          options[:threads] = 1 # for consistency
+        end
         if options[:timeout]
           warning '--benchmark ignores --timeout'
         end

From 78e1855508caef378151b965512076dbc65b3510 Mon Sep 17 00:00:00 2001
From: Adam Doppelt <amd@gurge.com>
Date: Thu, 2 Oct 2025 08:17:49 -0700
Subject: [PATCH 7/9] --benchmark isolated

---
 lib/image_optim/runner/option_parser.rb | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/image_optim/runner/option_parser.rb b/lib/image_optim/runner/option_parser.rb
index f051d98e..270d09e9 100644
--- a/lib/image_optim/runner/option_parser.rb
+++ b/lib/image_optim/runner/option_parser.rb
@@ -154,8 +154,12 @@ def wrap_regex(width)
   end
 
   op.separator nil
-  op.on('--benchmark', 'Run in benchmark mode, to compare tools without modifying images') do
-    options[:benchmark] = true
+  op.on('--benchmark [MODE]', String, 'Run benchmarks, to compare tools without modifying images (defaults ' \
+                                      'to `isolated` mode)') do |benchmark|
+    options[:benchmark] = benchmark || 'isolated'
+    if options[:benchmark] != 'isolated'
+      fail OptionParser::ParseError, '--benchmark must be `isolated`'
+    end
   end
 
   op.separator nil

From ddcfe7536820101f2dfd3485be7ffd0819a96b2a Mon Sep 17 00:00:00 2001
From: Adam Doppelt <amd@gurge.com>
Date: Sat, 4 Oct 2025 20:24:36 -0700
Subject: [PATCH 8/9] PR feedback

---
 lib/image_optim.rb                      |  2 ++
 lib/image_optim/runner/option_parser.rb | 12 ++++++------
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/lib/image_optim.rb b/lib/image_optim.rb
index dcf0e33c..027f479a 100644
--- a/lib/image_optim.rb
+++ b/lib/image_optim.rb
@@ -25,6 +25,7 @@
 end
 
 # Main interface
+# rubocop:disable Metrics/ClassLength
 class ImageOptim
   # Nice level
   attr_reader :nice
@@ -296,3 +297,4 @@ def apply_threading(enum)
     end
   end
 end
+# rubocop:enable Metrics/ClassLength
diff --git a/lib/image_optim/runner/option_parser.rb b/lib/image_optim/runner/option_parser.rb
index 270d09e9..ad6a21f9 100644
--- a/lib/image_optim/runner/option_parser.rb
+++ b/lib/image_optim/runner/option_parser.rb
@@ -154,12 +154,12 @@ def wrap_regex(width)
   end
 
   op.separator nil
-  op.on('--benchmark [MODE]', String, 'Run benchmarks, to compare tools without modifying images (defaults ' \
-                                      'to `isolated` mode)') do |benchmark|
-    options[:benchmark] = benchmark || 'isolated'
-    if options[:benchmark] != 'isolated'
-      fail OptionParser::ParseError, '--benchmark must be `isolated`'
-    end
+  op.on(
+    '--benchmark TYPE',
+    [:isolated],
+    'Run benchmarks, to compare tools without modifying images. `isolated` is the only supported type so far.'
+  ) do |benchmark|
+    options[:benchmark] = benchmark
   end
 
   op.separator nil

From 419eff26c9fd814f58871a901f7b79b8fa074e10 Mon Sep 17 00:00:00 2001
From: Adam Doppelt <amd@gurge.com>
Date: Sat, 4 Oct 2025 20:26:19 -0700
Subject: [PATCH 9/9] PR feedback

---
 .rubocop.yml       | 2 ++
 lib/image_optim.rb | 2 --
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/.rubocop.yml b/.rubocop.yml
index fe795817..2ef5056a 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -67,6 +67,8 @@ Metrics/BlockLength:
     - 'spec/**/*.rb'
 
 Metrics/ClassLength:
+  Exclude:
+    - 'lib/image_optim.rb'
   Max: 150
 
 Metrics/CyclomaticComplexity:
diff --git a/lib/image_optim.rb b/lib/image_optim.rb
index 027f479a..dcf0e33c 100644
--- a/lib/image_optim.rb
+++ b/lib/image_optim.rb
@@ -25,7 +25,6 @@
 end
 
 # Main interface
-# rubocop:disable Metrics/ClassLength
 class ImageOptim
   # Nice level
   attr_reader :nice
@@ -297,4 +296,3 @@ def apply_threading(enum)
     end
   end
 end
-# rubocop:enable Metrics/ClassLength