Carve out sudo commands for sudoers NOPASSWD

lib/cpu_config.rb

@@ -2,6 +2,11 @@
 
 # Manages CPU frequency and turbo boost configuration for benchmark consistency
 class CPUConfig
+  # These scripts are separate commands so that sudoers can allow just them
+  # with NOPASSWD, skipping the password prompt.
+  TURBO_BOOST_COMMAND = File.expand_path('../misc/turbo_boost', __dir__)
+  MAXIMIZE_FREQUENCY_COMMAND = File.expand_path('../misc/maximize_frequency', __dir__)
+
   class << self
     # Configure CPU for benchmarking: disable frequency scaling and verify settings
     def configure_for_benchmarking(turbo:)
@@ -42,11 +47,14 @@ def frequency_maximized?
   end
 
   def disable_turbo_boost
-    # Override in subclasses
+    # sudo requires the flag '-S' in order to take input from stdin
+    BenchmarkRunner.check_call("sudo -S #{TURBO_BOOST_COMMAND} off")
+    at_exit { sudo_prefer_quiet("#{TURBO_BOOST_COMMAND} on") }
   end
 
   def maximize_frequency
-    # Override in subclasses
+    # Disabling Turbo Boost reduces the CPU frequency, so this should be run after that.
+    BenchmarkRunner.check_call("sudo -S #{MAXIMIZE_FREQUENCY_COMMAND}")
   end
 
   def check_pstate(turbo:)
@@ -75,17 +83,6 @@ 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 #{TURBO_DISABLED_VALUE} > #{NO_TURBO_PATH}'")
-    at_exit { sudo_prefer_quiet("sh -c 'echo 0 > #{NO_TURBO_PATH}'") }
-  end
-
-  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 #{FREQUENCY_MAXIMIZED_VALUE} > #{MIN_PERF_PCT_PATH}'")
-  end
-
   def turbo_disabled?
     @turbo_disabled ||= File.exist?(NO_TURBO_PATH) &&
       File.read(NO_TURBO_PATH).strip == TURBO_DISABLED_VALUE
@@ -99,13 +96,13 @@ def frequency_maximized?
   def check_pstate(turbo:)
     unless turbo || turbo_disabled?
       puts("You forgot to disable turbo:")
-      puts("  sudo sh -c 'echo #{TURBO_DISABLED_VALUE} > #{NO_TURBO_PATH}'")
+      puts("  sudo #{TURBO_BOOST_COMMAND} off")
       exit(-1)
     end
 
     unless frequency_maximized?
       puts("You forgot to set the min perf percentage to 100:")
-      puts("  sudo sh -c 'echo #{FREQUENCY_MAXIMIZED_VALUE} > #{MIN_PERF_PCT_PATH}'")
+      puts("  sudo #{MAXIMIZE_FREQUENCY_COMMAND}")
       exit(-1)
     end
   end
@@ -117,21 +114,10 @@ class AMDCPUConfig < CPUConfig
   BOOST_PATH = "#{CPUFREQ_DIR}/boost"
   SCALING_GOVERNOR_GLOB = '/sys/devices/system/cpu/cpu*/cpufreq/scaling_governor'
   TURBO_DISABLED_VALUE = '0'
-  TURBO_ENABLED_VALUE = '1'
   PERFORMANCE_GOVERNOR = 'performance'
 
   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 #{TURBO_DISABLED_VALUE} > #{BOOST_PATH}'")
-    at_exit { sudo_prefer_quiet("sh -c 'echo #{TURBO_ENABLED_VALUE} > #{BOOST_PATH}'") }
-  end
-
-  def maximize_frequency
-    BenchmarkRunner.check_call("sudo -S cpupower frequency-set -g performance")
-  end
-
   def turbo_disabled?
     @turbo_disabled ||= File.exist?(BOOST_PATH) &&
       File.read(BOOST_PATH).strip == TURBO_DISABLED_VALUE
@@ -146,13 +132,13 @@ def frequency_maximized?
   def check_pstate(turbo:)
     unless turbo || turbo_disabled?
       puts("You forgot to disable boost:")
-      puts("  sudo sh -c 'echo #{TURBO_DISABLED_VALUE} > #{BOOST_PATH}'")
+      puts("  sudo #{TURBO_BOOST_COMMAND} off")
       exit(-1)
     end
 
     unless frequency_maximized?
       puts("You forgot to set the performance governor:")
-      puts("  sudo cpupower frequency-set -g #{PERFORMANCE_GOVERNOR}")
+      puts("  sudo #{MAXIMIZE_FREQUENCY_COMMAND}")
       exit(-1)
     end
   end

misc/maximize_frequency

@@ -0,0 +1,18 @@
+#!/bin/sh
+# Maximize the minimum CPU frequency for stable benchmark results:
+# min_perf_pct=100 on Intel pstate, or the performance governor on AMD cpufreq.
+# run_benchmarks.rb runs this with sudo. Allowing this command in sudoers
+# with NOPASSWD skips the password prompt.
+set -eu
+
+INTEL_MIN_PERF_PCT=/sys/devices/system/cpu/intel_pstate/min_perf_pct
+AMD_BOOST=/sys/devices/system/cpu/cpufreq/boost
+
+if [ -e "$INTEL_MIN_PERF_PCT" ]; then
+  echo 100 > "$INTEL_MIN_PERF_PCT"
+elif [ -e "$AMD_BOOST" ]; then
+  cpupower frequency-set -g performance
+else
+  echo "$0: no CPU frequency control found under /sys" >&2
+  exit 1
+fi

misc/turbo_boost

@@ -0,0 +1,23 @@
+#!/bin/sh
+# Enable or disable CPU turbo boost (Intel pstate or AMD cpufreq).
+# run_benchmarks.rb runs this with sudo. Allowing this command in sudoers
+# with NOPASSWD skips the password prompt.
+set -eu
+
+INTEL_NO_TURBO=/sys/devices/system/cpu/intel_pstate/no_turbo
+AMD_BOOST=/sys/devices/system/cpu/cpufreq/boost
+
+case "${1:-}" in
+  on)  intel_value=0 amd_value=1 ;;
+  off) intel_value=1 amd_value=0 ;;
+  *)   echo "Usage: $0 {on|off}" >&2; exit 1 ;;
+esac
+
+if [ -e "$INTEL_NO_TURBO" ]; then
+  echo "$intel_value" > "$INTEL_NO_TURBO"
+elif [ -e "$AMD_BOOST" ]; then
+  echo "$amd_value" > "$AMD_BOOST"
+else
+  echo "$0: no turbo boost control found under /sys" >&2
+  exit 1
+fi

test/cpu_config_test.rb

@@ -163,7 +163,7 @@
       end
 
       assert_equal 1, cleanup_commands.length, "at_exit block should call check_call once"
-      assert_equal "sudo -n sh -c 'echo 0 > /sys/devices/system/cpu/intel_pstate/no_turbo'", cleanup_commands[0][:cmd]
+      assert_equal "sudo -n #{CPUConfig::TURBO_BOOST_COMMAND} on", cleanup_commands[0][:cmd]
       assert_equal({ quiet: true, raise_error: false }, cleanup_commands[0][:opts])
     end
 
@@ -192,7 +192,7 @@
 
       assert_equal(-1, exit_code)
       assert_includes output[0], "You forgot to disable turbo"
-      assert_includes output[0], "sudo sh -c 'echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo'"
+      assert_includes output[0], "sudo #{CPUConfig::TURBO_BOOST_COMMAND} off"
     end
 
     it 'exits when Intel min perf is not 100%' do
@@ -220,7 +220,7 @@
 
       assert_equal(-1, exit_code)
       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'"
+      assert_includes output[0], "sudo #{CPUConfig::MAXIMIZE_FREQUENCY_COMMAND}"
     end
   end
 end
@@ -306,7 +306,7 @@
       end
 
       assert_equal 1, cleanup_commands.length, "at_exit block should call check_call once"
-      assert_equal "sudo -n sh -c 'echo 1 > /sys/devices/system/cpu/cpufreq/boost'", cleanup_commands[0][:cmd]
+      assert_equal "sudo -n #{CPUConfig::TURBO_BOOST_COMMAND} on", cleanup_commands[0][:cmd]
       assert_equal({ quiet: true, raise_error: false }, cleanup_commands[0][:opts])
     end
 
@@ -337,7 +337,7 @@
 
       assert_equal(-1, exit_code)
       assert_includes output[0], "You forgot to disable boost"
-      assert_includes output[0], "sudo sh -c 'echo 0 > /sys/devices/system/cpu/cpufreq/boost'"
+      assert_includes output[0], "sudo #{CPUConfig::TURBO_BOOST_COMMAND} off"
     end
 
     it 'exits when AMD performance governor is not set' do
@@ -367,7 +367,7 @@
 
       assert_equal(-1, exit_code)
       assert_includes output[0], "You forgot to set the performance governor"
-      assert_includes output[0], "sudo cpupower frequency-set -g performance"
+      assert_includes output[0], "sudo #{CPUConfig::MAXIMIZE_FREQUENCY_COMMAND}"
     end
   end
 end