lua coroutine vs plain loop

test.lua

require 'sys'
local n = 100000
local seq = {}
for i = 1, n do seq[i] = i end


local bs = 405
local plainLoop = function()
  local yield = {}
  for i = 1, #seq do
    table.insert( yield, seq[i] )
    if #yield == bs then
      print(#yield)
      yield = {}
    end
  end
  if #yield > 0 then
    print(#yield)
  end
end

local coroutineYield = function()
  local yield = {}
  for i = 1, #seq do
    table.insert( yield, seq[i] )
    if #yield == bs then
      coroutine.yield(yield)
      yield = {}
    end
  end
  if #yield > 0 then
      coroutine.yield(yield)
  end
  end

local coroutineLoop = function()
  local iter = coroutine.wrap( coroutineYield )
  for r in iter do
    print(#r)
  end
end

sys.tic()
plainLoop()
local t1 = sys.toc()

sys.tic()
coroutineLoop()
local t2 = sys.toc()

print( "plain loop", t1 )
print( "coroutine", t2 ) 

--[[
plain loop      0.0047900676727295
coroutine       0.0039558410644531
--]]