run `$ ./src/luajit bench.lua 16 <path-to-payload>`. 16 is the recommended argument in `PARAM_x86.txt`

bench.lua

local misc = require("misc")
local jit = require("jit")
local os = require("os")
local io = require("io")

local N_RUNS = 15

local function avg(n, func)
  local sum = 0
  for _ = 1, n do
    local old_out = io.output()
    io.output("/dev/null")
    jit.flush()
    collectgarbage()
    local start = os.clock()

    func()

    local stop = os.clock()
    sum = sum + (stop - start)
    io.output(old_out)
    print('   -> '..(stop - start))
    io.flush()
  end
  print(' avg: '..(sum / n))
  io.flush()
end

local function run_bench()
  avg(N_RUNS, function()
    local payload = assert(loadfile(arg[#arg]))

    local res, err = misc.memprof.start('/dev/null')
    assert(res, err)

    payload()

    res, err = misc.memprof.stop()
    assert(res, err)
  end)
end

print('JIT-OFF')
jit.off()

run_bench()

print('JIT-ON')
jit.on()

run_bench()