perf.lua

local ffi = require "ffi"

ffi.cdef [[
  bool QueryPerformanceFrequency(int64_t *lpFrequency);
  bool QueryPerformanceCounter(int64_t *lpPerformanceCount);
]]

local ptr_freq = ffi.new("int64_t[1]")
local ptr_tick = ffi.new("int64_t[1]")

local function get_time()
  if not ffi.C.QueryPerformanceFrequency(ptr_freq) then
    error("QueryPerformanceFrequency() failed")
  end

  if not ffi.C.QueryPerformanceCounter(ptr_tick) then
    error("QueryPerformanceCounter() failed")
  end

  return tonumber(ptr_tick[0]) / tonumber(ptr_freq[0])
end

local time_start

function _G.perfStart()
  time_start = get_time()
end

function _G.perfEnd(name)
  local time_total = get_time() - time_start
  print(name .. ": " .. time_total * 1000 .. " ms")
end

_G.ts.expose("perfStart")
_G.ts.expose("perfEnd")