Split CPU config into Intel and AMD classes

Author: rafaelfranca

lib/cpu_config.rb

@@ -2,14 +2,21 @@
 
 # Manages CPU frequency and turbo boost configuration for benchmark consistency
 class CPUConfig
-  # Configure CPU for benchmarking: disable frequency scaling and verify settings
-  def self.configure_for_benchmarking(turbo:)
-    new.configure_for_benchmarking(turbo: turbo)
-  end
+  class << self
+    # Configure CPU for benchmarking: disable frequency scaling and verify settings
+    def configure_for_benchmarking(turbo:)
+      build.configure_for_benchmarking(turbo: turbo)
+    end
 
-  def initialize
-    @intel_cpu = File.exist?('/sys/devices/system/cpu/intel_pstate')
-    @amd_cpu = File.exist?('/sys/devices/system/cpu/cpufreq/boost')
+    def build
+      if File.exist?('/sys/devices/system/cpu/intel_pstate')
+        IntelCPUConfig.new
+      elsif File.exist?('/sys/devices/system/cpu/cpufreq/boost')
+        AMDCPUConfig.new
+      else
+        NullCPUConfig.new
+      end
+    end
   end
 
   def configure_for_benchmarking(turbo:)
@@ -19,97 +26,123 @@ def configure_for_benchmarking(turbo:)
 
   private
 
-  # Disable Turbo Boost while running benchmarks. Maximize the CPU frequency.
   def disable_frequency_scaling(turbo:)
-    if intel_cpu?
-      disable_intel_turbo unless turbo
-      maximize_intel_frequency
-    elsif amd_cpu?
-      disable_amd_boost unless turbo
-      set_performance_governor
-    end
+    disable_turbo_boost unless turbo || turbo_disabled?
+    maximize_frequency unless frequency_maximized?
+  end
+
+  def turbo_disabled?
+    # Override in subclasses
+    false
   end
 
-  def intel_cpu?
-    @intel_cpu
+  def frequency_maximized?
+    # Override in subclasses
+    false
   end
 
-  def amd_cpu?
-    @amd_cpu
+  def disable_turbo_boost
+    # Override in subclasses
   end
 
-  def disable_intel_turbo
-    return if intel_no_turbo?
+  def maximize_frequency
+    # Override in subclasses
+  end
+
+  def check_pstate(turbo:)
+    # Override in subclasses
+  end
+end
+
+# Intel CPU configuration
+class IntelCPUConfig < CPUConfig
+  private
+
+  def disable_turbo_boost
     # sudo requires the flag '-S' in order to take input from stdin
     BenchmarkRunner.check_call("sudo -S sh -c 'echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo'")
     at_exit { BenchmarkRunner.check_call("sudo -S sh -c 'echo 0 > /sys/devices/system/cpu/intel_pstate/no_turbo'", quiet: true) }
   end
 
-  def maximize_intel_frequency
-    return if intel_perf_100pct?
+  def maximize_frequency
     # Disabling Turbo Boost reduces the CPU frequency, so this should be run after that.
     BenchmarkRunner.check_call("sudo -S sh -c 'echo 100 > /sys/devices/system/cpu/intel_pstate/min_perf_pct'")
   end
 
-  def disable_amd_boost
-    return if amd_no_boost?
-    # sudo requires the flag '-S' in order to take input from stdin
-    BenchmarkRunner.check_call("sudo -S sh -c 'echo 0 > /sys/devices/system/cpu/cpufreq/boost'")
-    at_exit { BenchmarkRunner.check_call("sudo -S sh -c 'echo 1 > /sys/devices/system/cpu/cpufreq/boost'", quiet: true) }
+  def turbo_disabled?
+    @turbo_disabled ||= File.exist?('/sys/devices/system/cpu/intel_pstate/no_turbo') &&
+      File.read('/sys/devices/system/cpu/intel_pstate/no_turbo').strip == '1'
   end
 
-  def set_performance_governor
-    return if performance_governor?
-    BenchmarkRunner.check_call("sudo -S cpupower frequency-set -g performance")
+  def frequency_maximized?
+    @frequency_maximized ||= File.exist?('/sys/devices/system/cpu/intel_pstate/min_perf_pct') &&
+      File.read('/sys/devices/system/cpu/intel_pstate/min_perf_pct').strip == '100'
   end
 
-  def intel_no_turbo?
-    File.exist?('/sys/devices/system/cpu/intel_pstate/no_turbo') &&
-      File.read('/sys/devices/system/cpu/intel_pstate/no_turbo').strip == '1'
+  def check_pstate(turbo:)
+    unless turbo || turbo_disabled?
+      puts("You forgot to disable turbo:")
+      puts("  sudo sh -c 'echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo'")
+      exit(-1)
+    end
+
+    unless frequency_maximized?
+      puts("You forgot to set the min perf percentage to 100:")
+      puts("  sudo sh -c 'echo 100 > /sys/devices/system/cpu/intel_pstate/min_perf_pct'")
+      exit(-1)
+    end
   end
+end
 
-  def intel_perf_100pct?
-    File.exist?('/sys/devices/system/cpu/intel_pstate/min_perf_pct') &&
-      File.read('/sys/devices/system/cpu/intel_pstate/min_perf_pct').strip == '100'
+# AMD CPU configuration
+class AMDCPUConfig < CPUConfig
+  private
+
+  def disable_turbo_boost
+    # sudo requires the flag '-S' in order to take input from stdin
+    BenchmarkRunner.check_call("sudo -S sh -c 'echo 0 > /sys/devices/system/cpu/cpufreq/boost'")
+    at_exit { BenchmarkRunner.check_call("sudo -S sh -c 'echo 1 > /sys/devices/system/cpu/cpufreq/boost'", quiet: true) }
   end
 
-  def amd_no_boost?
-    File.exist?('/sys/devices/system/cpu/cpufreq/boost') &&
+  def maximize_frequency
+    BenchmarkRunner.check_call("sudo -S cpupower frequency-set -g performance")
+  end
+
+  def turbo_disabled?
+    @turbo_disabled ||= File.exist?('/sys/devices/system/cpu/cpufreq/boost') &&
       File.read('/sys/devices/system/cpu/cpufreq/boost').strip == '0'
   end
 
-  def performance_governor?
-    Dir.glob('/sys/devices/system/cpu/cpu*/cpufreq/scaling_governor').all? do |governor|
+  def frequency_maximized?
+    @frequency_maximized ||= Dir.glob('/sys/devices/system/cpu/cpu*/cpufreq/scaling_governor').all? do |governor|
       File.read(governor).strip == 'performance'
     end
   end
 
-  # Verify that CPU frequency settings have been configured correctly
   def check_pstate(turbo:)
-    if intel_cpu?
-      unless turbo || intel_no_turbo?
-        puts("You forgot to disable turbo:")
-        puts("  sudo sh -c 'echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo'")
-        exit(-1)
-      end
-
-      unless intel_perf_100pct?
-        puts("You forgot to set the min perf percentage to 100:")
-        puts("  sudo sh -c 'echo 100 > /sys/devices/system/cpu/intel_pstate/min_perf_pct'")
-        exit(-1)
-      end
-    elsif amd_cpu?
-      unless turbo || amd_no_boost?
-        puts("You forgot to disable boost:")
-        puts("  sudo sh -c 'echo 0 > /sys/devices/system/cpu/cpufreq/boost'")
-        exit(-1)
-      end
+    unless turbo || turbo_disabled?
+      puts("You forgot to disable boost:")
+      puts("  sudo sh -c 'echo 0 > /sys/devices/system/cpu/cpufreq/boost'")
+      exit(-1)
+    end
 
-      unless performance_governor?
-        puts("You forgot to set the performance governor:")
-        puts("  sudo cpupower frequency-set -g performance")
-        exit(-1)
-      end
+    unless frequency_maximized?
+      puts("You forgot to set the performance governor:")
+      puts("  sudo cpupower frequency-set -g performance")
+      exit(-1)
     end
   end
 end
+
+# Null object for unsupported CPUs
+class NullCPUConfig < CPUConfig
+  private
+
+  def disable_frequency_scaling(turbo:)
+    # Do nothing
+  end
+
+  def check_pstate(turbo:)
+    # Do nothing
+  end
+end

test/cpu_config_test.rb

@@ -3,14 +3,39 @@
 require_relative '../lib/benchmark_runner'
 
 describe CPUConfig do
+  describe '.build' do
+    it 'returns IntelCPUConfig when Intel pstate files exist' do
+      File.stub :exist?, ->(path) { path.include?('intel_pstate') } do
+        config = CPUConfig.build
+        assert_instance_of IntelCPUConfig, config
+      end
+    end
+
+    it 'returns AMDCPUConfig when AMD cpufreq files exist' do
+      File.stub :exist?, ->(path) { path.include?('cpufreq/boost') } do
+        config = CPUConfig.build
+        assert_instance_of AMDCPUConfig, config
+      end
+    end
+
+    it 'returns NullCPUConfig when no CPU files exist' do
+      File.stub :exist?, false do
+        config = CPUConfig.build
+        assert_instance_of NullCPUConfig, config
+      end
+    end
+  end
+end
+
+describe NullCPUConfig do
   describe '#configure_for_benchmarking' do
     it 'does nothing when CPU frequency files do not exist' do
       call_count = 0
       at_exit_called = false
       exit_called = false
 
       File.stub :exist?, false do
-        cpu_config = CPUConfig.new
+        cpu_config = NullCPUConfig.new
         cpu_config.stub :at_exit, ->(&block) { at_exit_called = true } do
           cpu_config.stub :exit, ->(code) { exit_called = true } do
             BenchmarkRunner.stub :check_call, ->(*_args, **_kwargs) { call_count += 1 } do
@@ -25,14 +50,18 @@
         end
       end
     end
+  end
+end
 
+describe IntelCPUConfig do
+  describe '#configure_for_benchmarking' do
     it 'does not call commands or exit when Intel CPU is already properly configured with turbo disabled' do
       call_count = 0
       at_exit_called = false
       exit_called = false
 
       File.stub :exist?, ->(path) { path.include?('intel_pstate') } do
-        cpu_config = CPUConfig.new
+        cpu_config = IntelCPUConfig.new
         cpu_config.stub :at_exit, ->(&block) { at_exit_called = true } do
           cpu_config.stub :exit, ->(code) { exit_called = true } do
             BenchmarkRunner.stub :check_call, ->(*_args, **_kwargs) { call_count += 1 } do
@@ -62,7 +91,7 @@
       exit_called = false
 
       File.stub :exist?, ->(path) { path.include?('intel_pstate') } do
-        cpu_config = CPUConfig.new
+        cpu_config = IntelCPUConfig.new
         cpu_config.stub :at_exit, ->(&block) { at_exit_called = true } do
           cpu_config.stub :exit, ->(code) { exit_called = true } do
             BenchmarkRunner.stub :check_call, ->(*_args, **_kwargs) { call_count += 1 } do
@@ -94,7 +123,7 @@
       read_count = 0
 
       File.stub :exist?, ->(path) { path.include?('intel_pstate') } do
-        cpu_config = CPUConfig.new
+        cpu_config = IntelCPUConfig.new
         cpu_config.stub :at_exit, ->(&block) { at_exit_called = true; at_exit_block = block } do
           cpu_config.stub :exit, ->(code) { exit_called = true } do
             BenchmarkRunner.stub :check_call, ->(*_args, **_kwargs) { call_count += 1 } do
@@ -138,7 +167,7 @@
       exit_code = nil
       output = capture_io do
         File.stub :exist?, ->(path) { path.include?('intel_pstate') } do
-          cpu_config = CPUConfig.new
+          cpu_config = IntelCPUConfig.new
           cpu_config.stub :at_exit, ->(&block) {} do
             cpu_config.stub :exit, ->(code) { exit_code = code } do
               BenchmarkRunner.stub :check_call, ->(*_args, **_kwargs) {} do
@@ -166,7 +195,7 @@
       exit_code = nil
       output = capture_io do
         File.stub :exist?, ->(path) { path.include?('intel_pstate') } do
-          cpu_config = CPUConfig.new
+          cpu_config = IntelCPUConfig.new
           cpu_config.stub :at_exit, ->(&block) {} do
             cpu_config.stub :exit, ->(code) { exit_code = code } do
               BenchmarkRunner.stub :check_call, ->(*_args, **_kwargs) {} do
@@ -189,14 +218,18 @@
       assert_includes output[0], "You forgot to set the min perf percentage to 100"
       assert_includes output[0], "sudo sh -c 'echo 100 > /sys/devices/system/cpu/intel_pstate/min_perf_pct'"
     end
+  end
+end
 
+describe AMDCPUConfig do
+  describe '#configure_for_benchmarking' do
     it 'does not call commands or exit when AMD CPU is already properly configured with turbo disabled' do
       call_count = 0
       at_exit_called = false
       exit_called = false
 
       File.stub :exist?, ->(path) { path.include?('cpufreq/boost') } do
-        cpu_config = CPUConfig.new
+        cpu_config = AMDCPUConfig.new
         cpu_config.stub :at_exit, ->(&block) { at_exit_called = true } do
           cpu_config.stub :exit, ->(code) { exit_called = true } do
             BenchmarkRunner.stub :check_call, ->(*_args, **_kwargs) { call_count += 1 } do
@@ -230,7 +263,7 @@
       read_count = 0
 
       File.stub :exist?, ->(path) { path.include?('cpufreq/boost') } do
-        cpu_config = CPUConfig.new
+        cpu_config = AMDCPUConfig.new
         cpu_config.stub :at_exit, ->(&block) { at_exit_called = true; at_exit_block = block } do
           cpu_config.stub :exit, ->(code) { exit_called = true } do
             BenchmarkRunner.stub :check_call, ->(*_args, **_kwargs) { call_count += 1 } do
@@ -273,7 +306,7 @@
       exit_code = nil
       output = capture_io do
         File.stub :exist?, ->(path) { path.include?('cpufreq/boost') } do
-          cpu_config = CPUConfig.new
+          cpu_config = AMDCPUConfig.new
           cpu_config.stub :at_exit, ->(&block) {} do
             cpu_config.stub :exit, ->(code) { exit_code = code } do
               BenchmarkRunner.stub :check_call, ->(*_args, **_kwargs) {} do
@@ -303,7 +336,7 @@
       exit_code = nil
       output = capture_io do
         File.stub :exist?, ->(path) { path.include?('cpufreq/boost') } do
-          cpu_config = CPUConfig.new
+          cpu_config = AMDCPUConfig.new
           cpu_config.stub :at_exit, ->(&block) {} do
             cpu_config.stub :exit, ->(code) { exit_code = code } do
               BenchmarkRunner.stub :check_call, ->(*_args, **_kwargs) {} do