gsub_wo_block.rb

GC::Profiler.enable

vm_before = File.read("/proc/#{$$}/status").match(/^VmSize:\s*(\d*)/)[1].to_i

def vm_used(vm_before)
  File.read("/proc/#{$$}/status").match(/^VmSize:\s*(\d*)/)[1].to_i - vm_before
end

# w/o block
def gsub_wo(s)
  ["la ", "ko "].each{ |t| s.gsub!(/#{t}/, "") }
end

p [:before_string_build, vm_used(vm_before)]
s = ""
3495253.times { |i| s << "la " } #  ~10 Mb
3495253.times { |i| s << "ko " } #  ~10 Mb
p [:after_string_build, vm_used(vm_before)]

p [:before_gsub_wo_block, vm_used(vm_before)]
gsub_wo(s)
p [:after_gsub_wo_block, vm_used(vm_before)]

p [:before_gc_start, vm_used(vm_before)]
GC.start
p [:after_gc_start, vm_used(vm_before)]

GC::Profiler.report