benchmark: drop all bm_ prefix for legacy driver.rb

benchmark/*.rb is only benchmarks now. We don't need prefixes.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63928 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

benchmark/io_select3.rb

@@ -0,0 +1,21 @@
+# IO.select performance. a lot of fd
+
+ios = []
+nr = 100
+if defined?(Process::RLIMIT_NOFILE)
+  max = Process.getrlimit(Process::RLIMIT_NOFILE)[0]
+else
+  max = 64
+end
+puts "max fd: #{max} (results not apparent with <= 1024 max fd)"
+
+(max - 10).times do
+  r, w = IO.pipe
+  r.close
+  ios.push w
+end
+
+nr.times do
+  IO.select nil, ios
+end
+