Modernize Concurrent::Map benchmark

examples/benchmark_map.rb

@@ -1,35 +1,35 @@
 #!/usr/bin/env ruby
 
-require 'benchmark'
-require 'concurrent'
+require 'benchmark/ips'
+require 'concurrent/map'
 
-hash  = {}
+hash = {}
 map = Concurrent::Map.new
 
 ENTRIES = 10_000
 
 ENTRIES.times do |i|
-  hash[i]  = i
+  hash[i] = i
   map[i] = i
 end
 
-TESTS = 40_000_000
-Benchmark.bmbm do |results|
-  key = rand(10_000)
+TESTS = 1_000
+key = 2732 # srand(0) and rand(10_000)
 
+Benchmark.ips do |results|
   results.report('Hash#[]') do
-    TESTS.times { hash[key] }
+    hash[key]
   end
 
   results.report('Map#[]') do
-    TESTS.times { map[key] }
+    map[key]
   end
 
   results.report('Hash#each_pair') do
-    (TESTS / ENTRIES).times { hash.each_pair {|k,v| v} }
+    hash.each_pair { |k,v| v }
   end
 
   results.report('Map#each_pair') do
-    (TESTS / ENTRIES).times { map.each_pair {|k,v| v} }
+    map.each_pair { |k,v| v }
   end
 end