Microbenchmark for rb_sym2str under Ractors

Author: eightbitraptor

benchmarks.yml

@@ -255,6 +255,11 @@ throw:
 #
 # Ractor scaling benchmarks
 #
+symbol-name-ractor:
+  desc: repeatedly calls Symbol#name on a static symbol under the ractor harness to stress ID-to-string lookup.
+  ractor: true
+  ractor_only: true
+  default_harness: harness-ractor
 gvl_release_acquire:
   desc: microbenchmark designed to test how fast the gvl can be acquired and released between ractors.
   ractor: true

benchmarks/symbol-name-ractor/benchmark.rb

@@ -0,0 +1,18 @@
+require_relative "../../harness/loader"
+
+SYMBOL = :ruby_bench_id2str_pressure_static_symbol
+EXPECTED_NAME = SYMBOL.name
+ITERATIONS = Integer(ENV.fetch("SYMBOL_NAME_RACTOR_ITERS", 10_000_000))
+
+run_benchmark(5) do |num_ractors = 0|
+  iterations = num_ractors.zero? ? ITERATIONS : [ITERATIONS / num_ractors, 1].max
+
+  name = nil
+  i = 0
+  while i < iterations
+    name = SYMBOL.name
+    i += 1
+  end
+
+  raise "unexpected Symbol#name result" unless name.equal?(EXPECTED_NAME)
+end