Allow pinning to be specified in the benchmarks.yml

Author: eightbitraptor

benchmarks.yml

@@ -93,6 +93,7 @@ knucleotide:
   desc: k-nucleotide from the Computer Language Benchmarks Game - counts nucleotide frequencies using hash tables in parallel using Process.fork
 knucleotide-ractor:
   desc: k-nucleotide from the Computer Language Benchmarks Game - counts nucleotide frequencies using hash tables in parallel using Ractors
+  no_pinning: true
 lee:
   desc: lee is a circuit-board layout solver, deployed in a plausibly reality-like way
 matmul:

lib/argument_parser.rb

@@ -15,6 +15,7 @@ class ArgumentParser
     :rss,
     :graph,
     :no_pinning,
+    :force_pinning,
     :turbo,
     :skip_yjit,
     :with_pre_init,
@@ -140,6 +141,10 @@ def parse(argv)
         args.no_pinning = true
       end
 
+      opts.on("--force-pinning", "force pinning even for benchmarks marked no_pinning") do
+        args.force_pinning = true
+      end
+
       opts.on("--turbo", "don't disable CPU turbo boost") do
         args.turbo = true
       end
@@ -183,6 +188,7 @@ def default_args
       rss: false,
       graph: false,
       no_pinning: false,
+      force_pinning: false,
       turbo: false,
       skip_yjit: false,
       with_pre_init: nil,

lib/benchmark_runner/cli.rb

@@ -35,7 +35,8 @@ def run
         out_path: args.out_path,
         harness: args.harness,
         pre_init: args.with_pre_init,
-        no_pinning: args.no_pinning
+        no_pinning: args.no_pinning,
+        force_pinning: args.force_pinning
       )
 
       # Benchmark with and without YJIT

lib/benchmark_suite.rb

@@ -19,16 +19,17 @@ class BenchmarkSuite
   RACTOR_CATEGORY = ["ractor"].freeze
   RACTOR_HARNESS = "harness-ractor"
 
-  attr_reader :categories, :name_filters, :excludes, :out_path, :harness, :pre_init, :no_pinning, :bench_dir, :ractor_bench_dir
+  attr_reader :categories, :name_filters, :excludes, :out_path, :harness, :pre_init, :no_pinning, :force_pinning, :bench_dir, :ractor_bench_dir
 
-  def initialize(categories:, name_filters:, excludes: [], out_path:, harness:, pre_init: nil, no_pinning: false)
+  def initialize(categories:, name_filters:, excludes: [], out_path:, harness:, pre_init: nil, no_pinning: false, force_pinning: false)
     @categories = categories
     @name_filters = name_filters
     @excludes = excludes
     @out_path = out_path
     @harness = harness
     @pre_init = pre_init ? expand_pre_init(pre_init) : nil
     @no_pinning = no_pinning
+    @force_pinning = force_pinning
     @ractor_only = (categories == RACTOR_ONLY_CATEGORY)
 
     setup_benchmark_directories
@@ -41,13 +42,13 @@ def run(ruby:, ruby_description:)
     bench_failures = {}
 
     benchmark_entries = discover_benchmarks
-    cmd_prefix = base_cmd(ruby_description)
     env = benchmark_env(ruby)
 
     benchmark_entries.each_with_index do |entry, idx|
       puts("Running benchmark \"#{entry.name}\" (#{idx+1}/#{benchmark_entries.length})")
 
       result_json_path = File.join(out_path, "temp#{Process.pid}.json")
+      cmd_prefix = base_cmd(ruby_description, entry.name)
       result = run_single_benchmark(entry.script_path, result_json_path, ruby, cmd_prefix, env)
 
       if result[:success]
@@ -197,13 +198,13 @@ def linux?
   end
 
   # Set up the base command with CPU pinning if needed
-  def base_cmd(ruby_description)
+  def base_cmd(ruby_description, benchmark_name)
     if linux?
       cmd = setarch_prefix
 
       # Pin the process to one given core to improve caching and reduce variance on CRuby
       # Other Rubies need to use multiple cores, e.g., for JIT threads
-      if ruby_description.start_with?('ruby ') && !no_pinning
+      if ruby_description.start_with?('ruby ') && should_pin?(benchmark_name)
         # The last few cores of Intel CPU may be slow E-Cores, so avoid using the last one.
         cpu = [(Etc.nprocessors / 2) - 1, 0].max
         cmd.concat(["taskset", "-c", "#{cpu}"])
@@ -215,6 +216,14 @@ def base_cmd(ruby_description)
     end
   end
 
+  def should_pin?(benchmark_name)
+    return false if no_pinning
+    return true if force_pinning
+
+    benchmark_meta = benchmarks_metadata[benchmark_name] || {}
+    !benchmark_meta["no_pinning"]
+  end
+
   # Generate setarch prefix for Linux
   def setarch_prefix
     # Disable address space randomization (for determinism)