diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 72e84fc..73a77d1 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -23,9 +23,9 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        # Rutie 0.10, which the extension is built with, supports Ruby 2.5 to 2.7
+        # Rutie 0.13, which the extension is built with, supports Ruby 3.2 to 3.4
         os: [ubuntu-22.04, windows-latest]
-        ruby: ['2.5', '2.6', '2.7']
+        ruby: ['3.2', '3.3', '3.4']
         suite:
           - name: regression
             env: WITH_REGRESSION=true
@@ -35,7 +35,7 @@ jobs:
             env: ENCODING=true TEST_MONKEYPATCHES=true WITH_REGRESSION=true
         include:
           - os: macos-latest
-            ruby: '2.7'
+            ruby: '3.4'
             suite:
               name: regression
               env: WITH_REGRESSION=true
@@ -65,10 +65,10 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-22.04]
-        ruby: ['2.5', '2.6', '2.7']
+        ruby: ['3.2', '3.3', '3.4']
         include:
           - os: macos-latest
-            ruby: '2.7'
+            ruby: '3.4'
     steps:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@stable
diff --git a/.rubocop.yml b/.rubocop.yml
index 1bfaf38..129d8e0 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,4 +1,10 @@
+plugins:
+  - rubocop-performance
+
 AllCops:
+  TargetRubyVersion: 3.2
+  NewCops: disable
+  SuggestExtensions: false
   Include:
     - 'Gemfile'
     - 'Rakefile'
@@ -88,7 +94,7 @@ Layout/EndAlignment:
   Description: 'Align ends correctly.'
   Enabled: true
 
-Lint/EndInMethod:
+Style/EndBlock:
   Description: 'END blocks should not be placed inside method definitions.'
   Enabled: true
 
@@ -105,7 +111,7 @@ Lint/FormatParameterMismatch:
   Description: 'The number of parameters to format/sprint must match the fields.'
   Enabled: true
 
-Lint/HandleExceptions:
+Lint/SuppressedException:
   Description: "Don't suppress exception."
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#dont-hide-exceptions'
   Enabled: true
@@ -154,7 +160,7 @@ Lint/ShadowingOuterLocalVariable:
                  for block arguments or block local variables.
   Enabled: true
 
-Lint/StringConversionInInterpolation:
+Lint/RedundantStringCoercion:
   Description: 'Checks for Object#to_s usage in string interpolation.'
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#no-to-s'
   Enabled: true
@@ -186,7 +192,7 @@ Lint/UselessAssignment:
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#underscore-unused-vars'
   Enabled: true
 
-Lint/UselessComparison:
+Lint/BinaryOperatorWithIdenticalOperands:
   Description: 'Checks for comparison of something with itself.'
   Enabled: true
 
@@ -229,7 +235,7 @@ Metrics/CyclomaticComplexity:
                  of test cases needed to validate a method.
   Enabled: true
 
-Metrics/LineLength:
+Layout/LineLength:
   Description: 'Limit lines to 80 characters.'
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#80-character-limits'
   Enabled: false
@@ -290,7 +296,7 @@ Performance/ReverseEach:
   Reference: 'https://github.com/JuanitoFatas/fast-ruby#enumerablereverseeach-vs-enumerablereverse_each-code'
   Enabled: true
 
-Performance/Sample:
+Style/Sample:
   Description: >-
                   Use `sample` instead of `shuffle.first`,
                   `shuffle.last`, and `shuffle[Fixnum]`.
@@ -333,7 +339,7 @@ Performance/EndWith:
 Performance/FixedSize:
   Enabled: true
 
-Performance/LstripRstrip:
+Style/Strip:
   Enabled: true
 
 Performance/RangeInclude:
@@ -348,7 +354,7 @@ Performance/RedundantMatch:
 Performance/RedundantMerge:
   Enabled: true
 
-Performance/RedundantSortBy:
+Style/RedundantSortBy:
   Enabled: true
 
 Performance/RegexpMatch:
@@ -360,58 +366,6 @@ Performance/StartWith:
 Performance/TimesMap:
   Enabled: true
 
-##################### Rails ##################################
-
-Rails/ActionFilter:
-  Description: 'Enforces consistent use of action filter methods.'
-  Enabled: false
-
-Rails/Date:
-  Description: >-
-                  Checks the correct usage of date aware methods,
-                  such as Date.today, Date.current etc.
-  Enabled: false
-
-Rails/Delegate:
-  Description: 'Prefer delegate method for delegations.'
-  Enabled: false
-
-Rails/FindBy:
-  Description: 'Prefer find_by over where.first.'
-  Enabled: false
-
-Rails/FindEach:
-  Description: 'Prefer all.find_each over all.find.'
-  Enabled: false
-
-Rails/HasAndBelongsToMany:
-  Description: 'Prefer has_many :through to has_and_belongs_to_many.'
-  Enabled: false
-
-Rails/Output:
-  Description: 'Checks for calls to puts, print, etc.'
-  Enabled: false
-
-Rails/ReadWriteAttribute:
-  Description: >-
-                 Checks for read_attribute(:attr) and
-                 write_attribute(:attr, val).
-  Enabled: false
-
-Rails/ScopeArgs:
-  Description: 'Checks the arguments of ActiveRecord scopes.'
-  Enabled: false
-
-Rails/TimeZone:
-  Description: 'Checks the correct usage of time zone aware methods.'
-  StyleGuide: 'https://github.com/bbatsov/rails-style-guide#time'
-  Reference: 'http://danilenko.org/2012/7/6/rails_timezones'
-  Enabled: false
-
-Rails/Validation:
-  Description: 'Use validates :attribute, hash of validations.'
-  Enabled: false
-
 ################## Style #################################
 
 Layout/AccessModifierIndentation:
@@ -428,20 +382,20 @@ Style/Alias:
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#alias-method'
   Enabled: false
 
-Layout/AlignArray:
+Layout/ArrayAlignment:
   Description: >-
                  Align the elements of an array literal if they span more than
                  one line.
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#align-multiline-arrays'
   Enabled: true
 
-Layout/AlignHash:
+Layout/HashAlignment:
   Description: >-
                  Align the elements of a hash literal if they span more than
                  one line.
   Enabled: true
 
-Layout/AlignParameters:
+Layout/ParameterAlignment:
   Description: >-
                  Align the parameters of a method call if they span more
                  than one line. WRONG!  Only indent 2 (don't use this).
@@ -500,10 +454,6 @@ Style/BlockDelimiters:
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#single-line-blocks'
   Enabled: true
 
-Style/BracesAroundHashParameters:
-  Description: 'Enforce braces style around hash parameters.'
-  Enabled: false
-
 Style/CaseEquality:
   Description: 'Avoid explicit use of the case equality operator(===).'
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#no-case-equality'
@@ -640,11 +590,6 @@ Style/EmptyLiteral:
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#literal-array-hash'
   Enabled: false
 
-Style/EndBlock:
-  Description: 'Avoid the use of END blocks.'
-  StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#no-END-blocks'
-  Enabled: true
-
 Layout/EndOfLine:
   Description: 'Use Unix-style line endings.'
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#crlf'
@@ -673,7 +618,7 @@ Layout/FirstParameterIndentation:
   Description: 'Checks the indentation of the first parameter in a method call.'
   Enabled: false
 
-Style/FlipFlop:
+Lint/FlipFlop:
   Description: 'Checks for flip flops'
   StyleGuide: 'https://blog.newrelic.com/2015/02/24/weird-ruby-part-3-fun-flip-flop-phenom/'
   Enabled: true
@@ -727,13 +672,13 @@ Layout/IndentationWidth:
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#spaces-indentation'
   Enabled: true
 
-Layout/IndentArray:
+Layout/FirstArrayElementIndentation:
   Description: >-
                  Checks the indentation of the first element in an array
                  literal.
   Enabled: false
 
-Layout/IndentHash:
+Layout/FirstHashElementIndentation:
   Description: 'Checks the indentation of the first key in a hash literal.'
   Enabled: false
 
@@ -905,7 +850,7 @@ Style/PerlBackrefs:
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#no-perl-regexp-last-matchers'
   Enabled: true
 
-Naming/PredicateName:
+Naming/PredicatePrefix:
   Description: 'Check the names of predicate methods.'
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#bool-methods-qmark'
   Enabled: false
@@ -1111,12 +1056,12 @@ Style/SymbolProc:
   Description: 'Use symbols as procs instead of blocks when possible.'
   Enabled: false
 
-Layout/Tab:
+Layout/IndentationStyle:
   Description: 'No hard tabs.'
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#spaces-indentation'
   Enabled: true
 
-Layout/TrailingBlankLines:
+Layout/TrailingEmptyLines:
   Description: 'Checks trailing blank lines and final newline.'
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#newline-eof'
   Enabled: true
@@ -1153,11 +1098,11 @@ Style/UnlessElse:
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#no-else-with-unless'
   Enabled: true
 
-Style/UnneededCapitalW:
+Style/RedundantCapitalW:
   Description: 'Checks for %W when interpolation is not needed.'
   Enabled: true
 
-Style/UnneededPercentQ:
+Style/RedundantPercentQ:
   Description: 'Checks for %q/%Q when single quotes or double quotes would do.'
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#percent-q'
   Enabled: true
diff --git a/Cargo.lock b/Cargo.lock
index 0c87d7c..e53fcdd 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -30,9 +30,9 @@ checksum = "cf8baf1c55e62ffcace7a9f06f4bd9cd3f0c4beb022d3b367256b91b87513d98"
 
 [[package]]
 name = "rutie"
-version = "0.10.2"
+version = "0.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a97641d6bd3731d263d914141e960a8b515bf5ff4ca6c961b25ca4b2694c6490"
+checksum = "30d1529470ad0b69b81a6d0224632d00c01b46ef671452e24407512165b7ed84"
 dependencies = [
  "lazy_static",
  "libc",
diff --git a/Cargo.toml b/Cargo.toml
index 0982b33..ef15e93 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,5 +17,5 @@ name = "faster_path"
 crate-type = ["cdylib"]
 
 [dependencies]
-rutie = "0.10.2"
+rutie = "0.13.1"
 memchr = "2"
diff --git a/README.md b/README.md
index e160186..7ea200e 100644
--- a/README.md
+++ b/README.md
@@ -114,7 +114,7 @@ As mentioned earlier Sprockets, which handles assets, changed away from using `P
 
 ## Requirements
 
-* Ruby 2.5, 2.6 or 2.7 (the Rust extension is built with [Rutie](https://github.com/danielpclark/rutie) 0.10, which supports these)
+* Ruby 3.2, 3.3 or 3.4 (the Rust extension is built with [Rutie](https://github.com/danielpclark/rutie) 0.13, which supports these)
 * Rust 1.71 or later
 
 ## Installation
@@ -130,7 +130,7 @@ curl -sSf https://sh.rustup.rs | sh
 Add this line to your application's Gemfile:
 
 ```ruby
-gem 'faster_path', '~> 0.4.0'
+gem 'faster_path', '~> 0.5.0'
 ```
 
 And then execute:
@@ -159,25 +159,25 @@ require "faster_path"
 
 Current methods implemented:
 
-|FasterPath Rust Implementation|Ruby Implementation|Time Shaved Off (Ruby 2.7)|Time Shaved Off (Ruby 2.5)|
-|---|---|:---:|:---:|
-| `FasterPath.absolute?` | `Pathname#absolute?` | 95.7% | 96.7% |
-| `FasterPath.add_trailing_separator` | `Pathname#add_trailing_separator` | 85.4% | 83.0% |
-| `FasterPath.basename` | `File.basename` | 42.4% | 39.1% |
-| `FasterPath.children` | `Pathname#children` | 54.7% | 47.8% |
-| `FasterPath.chop_basename` | `Pathname#chop_basename` | 70.4% | 75.1% |
-| `FasterPath.cleanpath_aggressive` | `Pathname#cleanpath_aggressive` | 90.3% | 90.6% |
-| `FasterPath.cleanpath_conservative` | `Pathname#cleanpath_conservative` | 89.6% | 91.6% |
-| `FasterPath.del_trailing_separator` | `Pathname#del_trailing_separator` | 85.3% | 87.6% |
-| `FasterPath.directory?` | `Pathname#directory?` | 34.3% | 37.5% |
-| `FasterPath.dirname` | `File.dirname` | 56.8% | 54.7% |
-| `FasterPath.entries` | `Pathname#entries` | 38.0% | 33.9% |
-| `FasterPath.extname` | `File.extname` | 74.0% | 73.1% |
-| `FasterPath.has_trailing_separator?` | `Pathname#has_trailing_separator` | 88.5% | 89.1% |
-| `FasterPath.join` | `Pathname#join` | 88.1% | 90.3% |
-| `FasterPath.plus` | `Pathname#plus` | 91.7% | 93.4% |
-| `FasterPath.relative?` | `Pathname#relative?` | 92.8% | 95.2% |
-| `FasterPath.relative_path_from` | `Pathname#relative_path_from` | 92.5% | 93.6% |
+|FasterPath Rust Implementation|Ruby Implementation|Time Shaved Off (Ruby 3.4)|Time Shaved Off (Ruby 3.3)|Time Shaved Off (Ruby 3.2)|
+|---|---|:---:|:---:|:---:|
+| `FasterPath.absolute?` | `Pathname#absolute?` | 55.5% | 53.2% | 43.1% |
+| `FasterPath.add_trailing_separator` | `Pathname#add_trailing_separator` | 87.4% | 85.3% | 85.8% |
+| `FasterPath.basename` | `File.basename` | 30.7% | 22.2% | 27.5% |
+| `FasterPath.children` | `Pathname#children` | 65.0% | 55.1% | 55.4% |
+| `FasterPath.chop_basename` | `Pathname#chop_basename` | 75.3% | 73.5% | 72.8% |
+| `FasterPath.cleanpath_aggressive` | `Pathname#cleanpath_aggressive` | 92.4% | 92.2% | 92.4% |
+| `FasterPath.cleanpath_conservative` | `Pathname#cleanpath_conservative` | 91.4% | 91.3% | 91.8% |
+| `FasterPath.del_trailing_separator` | `Pathname#del_trailing_separator` | 89.1% | 87.9% | 87.8% |
+| `FasterPath.directory?` | `Pathname#directory?` | 41.5% | 39.9% | 44.2% |
+| `FasterPath.dirname` | `File.dirname` | 52.0% | 40.3% | 40.8% |
+| `FasterPath.entries` | `Pathname#entries` | 57.8% | 42.4% | 45.9% |
+| `FasterPath.extname` | `File.extname` | 69.4% | 66.7% | 69.2% |
+| `FasterPath.has_trailing_separator?` | `Pathname#has_trailing_separator` | 93.4% | 92.8% | 91.7% |
+| `FasterPath.join` | `Pathname#join` | 89.1% | 89.0% | 88.4% |
+| `FasterPath.plus` | `Pathname#plus` | 95.5% | 94.7% | 94.5% |
+| `FasterPath.relative?` | `Pathname#relative?` | 66.9% | 66.3% | 60.4% |
+| `FasterPath.relative_path_from` | `Pathname#relative_path_from` | 94.4% | 94.6% | 94.2% |
 
 See [Benchmarks](#benchmarks) for how these are measured.
 
@@ -205,10 +205,10 @@ FasterPath.sledgehammer_everything!
 
 These will **not** be included by default in monkey-patches.  To try them with monkeypatching use the environment flag of `WITH_REGRESSION`.  These methods are here to be improved upon.
 
-|FasterPath Implementation|Ruby Implementation|Time Shaved Off (Ruby 2.7)|Time Shaved Off (Ruby 2.5)|
-|---|---|:---:|:---:|
-| `FasterPath.entries_compat` | `Pathname.entries` | 16.8% | 9.2% |
-| `FasterPath.children_compat` | `Pathname.children` | 32.1% | 26.6% |
+|FasterPath Implementation|Ruby Implementation|Time Shaved Off (Ruby 3.4)|Time Shaved Off (Ruby 3.3)|Time Shaved Off (Ruby 3.2)|
+|---|---|:---:|:---:|:---:|
+| `FasterPath.entries_compat` | `Pathname.entries` | 35.7% | 22.0% | 15.9% |
+| `FasterPath.children_compat` | `Pathname.children` | 46.7% | 33.6% | 32.3% |
 
 It's been my observation (and some others) that the Rust implementation of the C code for `File` has similar results but
 performance seems to vary based on CPU cache on possibly 64bit/32bit system environments.  These are not included by default when the monkey patch method `FasterPath.sledgehammer_everything!` is executed.
@@ -216,13 +216,19 @@ performance seems to vary based on CPU cache on possibly 64bit/32bit system envi
 ## Benchmarks
 
 The "Time Shaved Off" figures come from the project's Pinch-bench (`rake pbench`, in
-`test/pbench`): each method runs against Ruby's own implementation, and the result is how much
-less time FasterPath took. They are the median of 3 runs of `LONG_RUN=10 rake pbench` (500,000
-calls of each method, 5 times) on Linux x86_64 with Ruby 2.7.8 and 2.5.7, built with Rust 1.97.
-Expect a few points of difference from run to run.
+`test/pbench`): each method runs against Ruby's own implementation, alternating with it round by
+round, and the result is how much less time FasterPath's best round took than Ruby's best round.
+They are the median of 3 runs of `LONG_RUN=30 rake pbench` (5 rounds of 300,000 calls of each
+method) on Linux x86_64, each run pinned to one CPU core, with Ruby 3.4.6, 3.3.6 and 3.2.9, built
+with Rust 1.97. The three runs agree within a few points for most methods; the ones that touch
+the filesystem (`children`, `directory?`, `entries`) vary the most.
+
+The figures are smaller than they were on Ruby 2 for the cheapest methods, `absolute?` and
+`relative?` above all: Ruby 3's own `Pathname#absolute?` is a single regexp match, where Ruby 2's
+walked the path with `chop_basename`, so there is less left to shave off.
 
 `rake pbench` is also the performance regression test: each method has a floor in
-`test/pbench/pbench_suite.rb` (about half of the improvement in the table above) and the task
+`test/pbench/pbench_suite.rb` (about half of its lowest figure in the table above) and the task
 fails when a method measures below it, so a change that makes a method slower shows up in
 `rake test`. On Windows, where `join` is currently slower than Ruby's
 ([#185](https://github.com/danielpclark/faster_path/issues/185)), the floors are reported but not
@@ -230,8 +236,10 @@ enforced.
 
 ### Before and after the Rutie 0.10 upgrade
 
-Measured the same way, alternating runs of the code before the upgrade (built with Rutie 0.6)
-and after it. Higher is better; the change is in percentage points.
+The last figures on Ruby 2, from the Rutie 0.10 upgrade (faster_path 0.4.0): Ruby 2.7.8 and
+2.5.7, alternating runs of the code before the upgrade (built with Rutie 0.6) and after it, with
+the benchmark then measuring the average of 5 rounds run one implementation after the other.
+Higher is better; the change is in percentage points.
 
 |Method|Ruby 2.7 before|Ruby 2.7 after|Change|Ruby 2.5 before|Ruby 2.5 after|Change|
 |---|:---:|:---:|:---:|:---:|:---:|:---:|
diff --git a/Rakefile b/Rakefile
index 1220540..67a07a4 100644
--- a/Rakefile
+++ b/Rakefile
@@ -92,10 +92,8 @@ Rake::TestTask.new(bench: :build_lib) do |t|
   t.pattern = 'test/**/*_benchmark.rb'
 end
 
+# LONG_RUN=<1..30> multiplies the calls per round, see test/pbench/pbench.rb
 Rake::TestTask.new(pbench: :build_lib) do |t|
-  if ARGV.last == '--long-run'
-    ENV['LONG_RUN'] = '10'
-  end
   t.libs = %w[lib test test/pbench]
   t.pattern = 'test/pbench/pbench_suite.rb'
 end
diff --git a/faster_path.gemspec b/faster_path.gemspec
index 9616f74..6c681b0 100644
--- a/faster_path.gemspec
+++ b/faster_path.gemspec
@@ -24,17 +24,20 @@ Gem::Specification.new do |spec|
   spec.extensions    = ['ext/Rakefile']
   spec.require_paths = ['lib']
 
-  # Rutie 0.10, which the Rust extension is built with, supports Ruby 2.5 to 2.7
-  spec.required_ruby_version = ['>= 2.5', '< 3.0']
+  # Rutie 0.13, which the Rust extension is built with, supports Ruby 3.2 to 3.4
+  spec.required_ruby_version = ['>= 3.2', '< 3.5']
 
   spec.add_dependency 'bundler', '>= 1.12'
   spec.add_dependency 'rake', '>= 12.3'
   spec.add_dependency 'thermite', '0.13.0'
+  # thermite reads GitHub release feeds with REXML, a bundled gem since Ruby 3.0
+  spec.add_dependency 'rexml', '~> 3.2'
   spec.add_development_dependency 'read_source', '~> 0.2.6'
   spec.add_development_dependency 'minitest', '~> 5.11'
   spec.add_development_dependency 'minitest-reporters', '~> 1.1'
   spec.add_development_dependency 'color_pound_spec_reporter', '~> 0.0.9'
-  spec.add_development_dependency 'rubocop', '0.53'
+  spec.add_development_dependency 'rubocop', '~> 1.80'
+  spec.add_development_dependency 'rubocop-performance', '~> 1.20'
   spec.add_development_dependency 'stop_watch', '~> 1.0'
   if !ENV['CI'] && ENV['GRAPH']
     spec.add_development_dependency 'gruff', '~> 0.7.0'
diff --git a/lib/faster_path/optional/monkeypatches.rb b/lib/faster_path/optional/monkeypatches.rb
index 70027af..9909bb6 100644
--- a/lib/faster_path/optional/monkeypatches.rb
+++ b/lib/faster_path/optional/monkeypatches.rb
@@ -24,10 +24,10 @@ def self.extname(pth)
         end
 
         # @private :nodoc:
-        def self.dirname(pth)
+        def self.dirname(pth, level = 1)
           pth = pth.to_path if pth.respond_to? :to_path
           raise TypeError unless pth.is_a? String
-          FasterPath.dirname(pth)
+          FasterPath.dirname(pth, level)
         end
       end
     end
diff --git a/lib/faster_path/optional/refinements.rb b/lib/faster_path/optional/refinements.rb
index f5149cd..c47911c 100644
--- a/lib/faster_path/optional/refinements.rb
+++ b/lib/faster_path/optional/refinements.rb
@@ -20,10 +20,10 @@ def self.extname(pth)
       end
 
       # @private :nodoc:
-      def self.dirname(pth)
+      def self.dirname(pth, level = 1)
         pth = pth.to_path if pth.respond_to? :to_path
         raise TypeError unless pth.is_a? String
-        FasterPath.dirname(pth)
+        FasterPath.dirname(pth, level)
       end
     end
   end
diff --git a/lib/faster_path/version.rb b/lib/faster_path/version.rb
index 54bd02d..7847e1a 100644
--- a/lib/faster_path/version.rb
+++ b/lib/faster_path/version.rb
@@ -1,3 +1,3 @@
 module FasterPath
-  VERSION = "0.4.0"
+  VERSION = "0.5.0"
 end
diff --git a/spec/mspec b/spec/mspec
index 0091e8a..5470479 160000
--- a/spec/mspec
+++ b/spec/mspec
@@ -1 +1 @@
-Subproject commit 0091e8a62e954717cd54641f935eaf1403692041
+Subproject commit 54704795e21128a930af2021c72c49cb87065134
diff --git a/spec/ruby_spec b/spec/ruby_spec
index c503335..97f0762 160000
--- a/spec/ruby_spec
+++ b/spec/ruby_spec
@@ -1 +1 @@
-Subproject commit c503335d3d9f6ec6ef24de60a0716c34af69b64f
+Subproject commit 97f076242b7fc6e60703e6a6053365065cd6fc30
diff --git a/src/pathname.rs b/src/pathname.rs
index 5a88f51..39950ed 100644
--- a/src/pathname.rs
+++ b/src/pathname.rs
@@ -3,7 +3,7 @@ use std::ffi::OsStr;
 use std::fs;
 use std::io;
 
-use rutie::{AnyException, AnyObject, Array, Boolean, Class, NilClass, Object, RString};
+use rutie::{AnyException, AnyObject, Array, Boolean, Class, Integer, NilClass, Object, RString, Symbol};
 
 use crate::basename;
 use crate::chop_basename::{self, is_relative};
@@ -15,7 +15,7 @@ use crate::path_parsing::Rules;
 use crate::plus;
 use crate::relative_path_from::{self, RelativePathError};
 use crate::ruby::{
-  argument_error, check_max_arguments, error, new_pathname, path_like_to_string, pathname_class,
+  argument_error, check_max_arguments, error, inspect, new_pathname, path_like_to_string, pathname_class,
   truthy_argument, EncodingId, EncodingOf, PathArgument, PathString, RubyResult,
 };
 
@@ -152,11 +152,51 @@ pub fn pn_is_directory(arguments: &[AnyObject]) -> RubyResult {
   Ok(Boolean::new(is_directory).into())
 }
 
+// `File.dirname(path, level = 1)`: `level` is the number of trailing
+// components to remove (Ruby 3.1+).
 pub fn pn_dirname(arguments: &[AnyObject]) -> RubyResult {
-  check_max_arguments(arguments, 1)?;
+  check_max_arguments(arguments, 2)?;
   let argument = PathArgument::new(arguments, 0)?;
   let path = argument.path()?;
-  Ok(path.to_ruby(&dirname::dirname(RULES, path.bytes())).into())
+  let level = match arguments.get(1) {
+    Some(level) => level_argument(level)?,
+    None => 1,
+  };
+  let mut result: Cow<[u8]> = Cow::Borrowed(path.bytes());
+  for _ in 0..level {
+    let parent = dirname::dirname(RULES, &result);
+    if *parent == *result {
+      // The root ("/", "." or "C:/"), which is its own dirname
+      break;
+    }
+    result = Cow::Owned(parent.into_owned());
+  }
+  if result.is_empty() {
+    // `File.dirname("", 0)` is "." like `File.dirname("")`
+    result = Cow::Borrowed(b".");
+  }
+  Ok(path.to_ruby(&result).into())
+}
+
+// The `level` argument of `File.dirname`, converted like Ruby's `NUM2INT`.
+fn level_argument(object: &AnyObject) -> Result<usize, AnyException> {
+  let integer = match object.try_convert_to::<Integer>() {
+    Ok(integer) => integer,
+    Err(_) => {
+      let responds = object.protect_send("respond_to?", &[Symbol::new("to_int").into()])?;
+      if !responds.value().is_true() {
+        let class_name = object.protect_send("class", &[]).ok().and_then(|class| inspect(&class).ok()).unwrap_or_default();
+        return Err(error(&Class::type_error(), &format!("no implicit conversion of {} into Integer", class_name)));
+      }
+      let converted = object.protect_send("to_int", &[])?;
+      converted.try_convert_to::<Integer>()?
+    }
+  };
+  let level = integer.to_i64();
+  if level < 0 {
+    return Err(argument_error(&format!("negative level: {}", level)));
+  }
+  Ok(level as usize)
 }
 
 // Returns an array of `String`s
@@ -315,7 +355,7 @@ fn system_call_error(err: &io::Error, path: &AnyObject, func: &str) -> AnyExcept
   #[cfg(unix)]
   {
     if let Some(errno) = err.raw_os_error() {
-      let arguments = [path.clone(), rutie::Integer::new(errno.into()).into(), RString::new_utf8(func).into()];
+      let arguments = [path.clone(), Integer::new(errno.into()).into(), RString::new_utf8(func).into()];
       if let Ok(exception) = Class::system_call_error().protect_send("new", &arguments) {
         if let Ok(exception) = exception.try_convert_to::<AnyException>() {
           return exception;
diff --git a/test/dirname_test.rb b/test/dirname_test.rb
index 4edcdf2..6cf69ab 100644
--- a/test/dirname_test.rb
+++ b/test/dirname_test.rb
@@ -11,6 +11,54 @@ def test_it_returns_all_the_components_of_filename_except_the_last_one
     assert_equal('/foo', FasterPath.dirname('/foo/foo'))
   end
 
+  def test_it_removes_level_trailing_components
+    assert_equal('/home', FasterPath.dirname('/home/jason/poot.txt', 2))
+    assert_equal('/home/jason', FasterPath.dirname('/home/jason', 0))
+    assert_equal('/', FasterPath.dirname('/home/jason', 2))
+    assert_equal('/', FasterPath.dirname('/home/jason', 10))
+    assert_equal('.', FasterPath.dirname('a/b', 2))
+    assert_equal('.', FasterPath.dirname('a/b', 10))
+    assert_equal('a', FasterPath.dirname('a//b//c//', 2))
+    assert_equal(String, FasterPath.dirname('/home/jason', 0).class)
+  end
+
+  # What File.dirname(path, level) returns on Ruby 3.3 for levels 0 to 4
+  LEVELS = {
+    '/home/jason/poot.txt' => ['/home/jason/poot.txt', '/home/jason', '/home', '/', '/'],
+    'a/b/c' => ['a/b/c', 'a/b', 'a', '.', '.'],
+    '/a' => ['/a', '/', '/', '/', '/'],
+    'a' => ['a', '.', '.', '.', '.'],
+    '' => ['.', '.', '.', '.', '.'],
+    '/' => ['/', '/', '/', '/', '/'],
+    './b/./' => ['./b/./', './b', '.', '.', '.'],
+    '/foo/../.' => ['/foo/../.', '/foo/..', '/foo', '/', '/'],
+    'a//b//c//' => ['a//b//c//', 'a//b', 'a', '.', '.']
+  }.freeze
+
+  def test_level_agrees_with_file_dirname
+    LEVELS.each do |path, expected|
+      expected.each_with_index do |dirname, level|
+        assert_equal(dirname, FasterPath.dirname(path, level), "#{path.inspect}, #{level}")
+      end
+    end
+  end
+
+  def test_level_is_converted_with_to_int
+    level = Object.new
+    def level.to_int
+      2
+    end
+    assert_equal('/home', FasterPath.dirname('/home/jason/poot.txt', level))
+  end
+
+  def test_level_must_be_a_non_negative_integer
+    error = assert_raises(ArgumentError) { FasterPath.dirname('/home/jason', -1) }
+    assert_equal('negative level: -1', error.message)
+    error = assert_raises(TypeError) { FasterPath.dirname('/home/jason', '1') }
+    assert_equal('no implicit conversion of String into Integer', error.message)
+    assert_raises(ArgumentError) { FasterPath.dirname('/home/jason', 1, 2) }
+  end
+
   def test_it_returns_a_string
     assert_kind_of(String, FasterPath.dirname("foo"))
   end
diff --git a/test/pbench/pbench.rb b/test/pbench/pbench.rb
index e6f4784..29ff011 100644
--- a/test/pbench/pbench.rb
+++ b/test/pbench/pbench.rb
@@ -22,31 +22,29 @@ def self.bench_range
     [10_000 * amplitude] * 5
   end
 
+  # The improvement of `new_impl` over `baseline`, in percent.
+  #
+  # The two run alternately, round by round, so that whatever else the
+  # machine is doing affects both alike, and each is measured by its best
+  # round: the slower rounds only show the interruptions, not the code.
   def performance(baseline, new_impl)
     range = self.class.bench_range
 
     times_a = []
-    range.each do |x|
-      GC.start
-      t0 = Minitest.clock_time
-      baseline.call(x)
-      t = Minitest.clock_time - t0
-      times_a << t
-    end
-
-    # This seems to stabalize the results a bit
-    sleep 0.02; GC.start
-
     times_b = []
     range.each do |x|
-      GC.start
-      t0 = Minitest.clock_time
-      new_impl.call(x)
-      t = Minitest.clock_time - t0
-      times_b << t
+      times_a << time(baseline, x)
+      times_b << time(new_impl, x)
     end
 
-    increase(average(times_a), average(times_b)).round(1)
+    increase(times_a.min, times_b.min).round(1)
+  end
+
+  def time(impl, x)
+    GC.start
+    t0 = Minitest.clock_time
+    impl.call(x)
+    Minitest.clock_time - t0
   end
 
   # run(hash)
diff --git a/test/pbench/pbench_suite.rb b/test/pbench/pbench_suite.rb
index 2d0c813..432827d 100644
--- a/test/pbench/pbench_suite.rb
+++ b/test/pbench/pbench_suite.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'pbench'
 
 # PBENCHES[:""] = {
@@ -45,7 +47,7 @@
   end
 }
 PBENCHES[:"absolute?"] = {
-  min: 80,
+  min: 20,
   new: lambda do |x|
     x.times do
       FasterPath.absolute?("/hello")
@@ -60,7 +62,7 @@
   end,
 }
 PBENCHES[:add_trailing_separator] = {
-  min: 50,
+  min: 40,
   new: lambda do |x|
     x.times do
       FasterPath.add_trailing_separator('/hello/world')
@@ -75,7 +77,7 @@
   end
 }
 PBENCHES[:basename] = {
-  min: 15,
+  min: 10,
   new: lambda do |x|
     x.times do
       FasterPath.basename("/hello/world")
@@ -123,7 +125,7 @@
  end
 }
 PBENCHES[:chop_basename] = {
-  min: 50,
+  min: 35,
   new: lambda do |x|
     x.times do
       FasterPath.chop_basename "/hello/world.txt"
@@ -142,7 +144,7 @@
 PATHNAME_CA1 = Pathname.new('/../.././../a').freeze
 PATHNAME_CA2 = Pathname.new('a/b/../../../../c/../d').freeze
 PBENCHES[:cleanpath_aggressive] = {
-  min: 80,
+  min: 45,
   new: lambda do |x|
     x.times do
       Pathname.new(FasterPath.cleanpath_aggressive '/../.././../a')
@@ -157,7 +159,7 @@
   end
 }
 PBENCHES[:cleanpath_conservative] = {
-  min: 80,
+  min: 45,
   new: lambda do |x|
     x.times do
       Pathname.new(FasterPath.cleanpath_conservative '/../.././../a')
@@ -172,7 +174,7 @@
   end
 }
 PBENCHES[:del_trailing_separator] = {
-  min: 70,
+  min: 40,
   new: lambda do |x|
     x.times do
       FasterPath.del_trailing_separator('/hello/world')
@@ -202,7 +204,7 @@
   end
 }
 PBENCHES[:dirname] = {
-  min: 30,
+  min: 20,
   new: lambda do |x|
     x.times do
       FasterPath.dirname "/really/long/path/name/which/ruby/doesnt/like/bar.txt"
@@ -248,7 +250,7 @@
   end
 }
 PBENCHES[:extname] = {
-  min: 50,
+  min: 30,
   new: lambda do |x|
     x.times do
       FasterPath.extname('verylongfilename_verylongfilename.rb')
@@ -265,7 +267,7 @@
   end
 }
 PBENCHES[:"has_trailing_separator?"] = {
-  min: 75,
+  min: 45,
   new: lambda do |x|
     x.times do
       FasterPath.has_trailing_separator? '////a//aaa/a//a/aaa////'
@@ -280,7 +282,7 @@
   end
 }
 PBENCHES[:join] = {
-  min: 70,
+  min: 40,
   new: lambda do |x|
     x.times do
       FasterPath.join('a', 'b')
@@ -297,7 +299,7 @@
   end
 }
 PBENCHES[:plus] = {
-  min: 80,
+  min: 45,
   new: lambda do |x|
     x.times do
       FasterPath.plus('a', 'b')
@@ -314,7 +316,7 @@
   end
 }
 PBENCHES[:"relative?"] = {
-  min: 80,
+  min: 30,
   new: lambda do |x|
     x.times do
       FasterPath.relative?("/hello")
@@ -331,7 +333,7 @@
 PATHNAME_AB = Pathname("/a/b")
 PATHNAME_ABCD = Pathname("/a/b/c/d")
 PBENCHES[:relative_path_from] = {
-  min: 80,
+  min: 45,
   new: lambda do |x|
     x.times do
       FasterPath.relative_path_from "/a/b/c/d", "/a/b"
diff --git a/test/refinements/dirname_test.rb b/test/refinements/dirname_test.rb
index 712592a..a590714 100644
--- a/test/refinements/dirname_test.rb
+++ b/test/refinements/dirname_test.rb
@@ -4,8 +4,8 @@
 
 class RefinedFile
   using FasterPath::RefineFile
-  def dirname(name)
-    File.dirname(name)
+  def dirname(name, *level)
+    File.dirname(name, *level)
   end
 end
 
@@ -45,4 +45,11 @@ def test_it_gets_dirnames_correctly
     assert_equal("/foo/..", @refined_file.dirname("/foo/../."))
     assert_equal("foo", @refined_file.dirname("foo/../"))
   end
+
+  def test_it_takes_a_level
+    assert_equal('/home', @refined_file.dirname('/home/jason/poot.txt', 2))
+    assert_equal('/home/jason', @refined_file.dirname('/home/jason', 0))
+    assert_equal('/', @refined_file.dirname('/home/jason', 10))
+    assert_raises(ArgumentError) { @refined_file.dirname('/home/jason', -1) }
+  end
 end