builtin/profiler/instrumentation.lua

   1 --Minetest
   2 --Copyright (C) 2016 T4im
   3 --
   4 --This program is free software; you can redistribute it and/or modify
   5 --it under the terms of the GNU Lesser General Public License as published by
   6 --the Free Software Foundation; either version 2.1 of the License, or
   7 --(at your option) any later version.
   8 --
   9 --This program is distributed in the hope that it will be useful,
  10 --but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 --MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 --GNU Lesser General Public License for more details.
  13 --
  14 --You should have received a copy of the GNU Lesser General Public License along
  15 --with this program; if not, write to the Free Software Foundation, Inc.,
  16 --51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17
  18 local format, pairs, type = string.format, pairs, type
  19 local core, get_current_modname = core, core.get_current_modname
  20 local profiler, sampler, get_bool_default = ...
  21
  22 local instrument_builtin = get_bool_default("instrument.builtin", false)
  23
  24 local register_functions = {
  25         register_globalstep = 0,
  26         register_playerevent = 0,
  27         register_on_placenode = 0,
  28         register_on_dignode = 0,
  29         register_on_punchnode = 0,
  30         register_on_generated = 0,
  31         register_on_newplayer = 0,
  32         register_on_dieplayer = 0,
  33         register_on_respawnplayer = 0,
  34         register_on_prejoinplayer = 0,
  35         register_on_joinplayer = 0,
  36         register_on_leaveplayer = 0,
  37         register_on_cheat = 0,
  38         register_on_chat_message = 0,
  39         register_on_player_receive_fields = 0,
  40         register_on_craft = 0,
  41         register_craft_predict = 0,
  42         register_on_protection_violation = 0,
  43         register_on_item_eat = 0,
  44         register_on_punchplayer = 0,
  45         register_on_player_hpchange = 0,
  46 }
  47
  48 ---
  49 -- Create an unique instrument name.
  50 -- Generate a missing label with a running index number.
  51 --
  52 local counts = {}
  53 local function generate_name(def)
  54         local class, label, func_name = def.class, def.label, def.func_name
  55         if label then
  56                 if class or func_name then
  57                         return format("%s '%s' %s", class or "", label, func_name or ""):trim()
  58                 end
  59                 return format("%s", label):trim()
  60         elseif label == false then
  61                 return format("%s", class or func_name):trim()
  62         end
  63
  64         local index_id = def.mod .. (class or func_name)
  65         local index = counts[index_id] or 1
  66         counts[index_id] = index + 1
  67         return format("%s[%d] %s", class or func_name, index, class and func_name or ""):trim()
  68 end
  69
  70 ---
  71 -- Keep `measure` and the closure in `instrument` lean, as these, and their
  72 -- directly called functions are the overhead that is caused by instrumentation.
  73 --
  74 local time, log = core.get_us_time, sampler.log
  75 local function measure(modname, instrument_name, start, ...)
  76         log(modname, instrument_name, time() - start)
  77         return ...
  78 end
  79 --- Automatically instrument a function to measure and log to the sampler.
  80 -- def = {
  81 --              mod = "",
  82 --              class = "",
  83 --              func_name = "",
  84 --              -- if nil, will create a label based on registration order
  85 --              label = "" | false,
  86 -- }
  87 local function instrument(def)
  88         if not def or not def.func then
  89                 return
  90         end
  91         def.mod = def.mod or get_current_modname() or "??"
  92         local modname = def.mod
  93         local instrument_name = generate_name(def)
  94         local func = def.func
  95
  96         if not instrument_builtin and modname == "*builtin*" then
  97                 return func
  98         end
  99
 100         return function(...)
 101                 -- This tail-call allows passing all return values of `func`
 102                 -- also called https://en.wikipedia.org/wiki/Continuation_passing_style
 103                 -- Compared to table creation and unpacking it won't lose `nil` returns
 104                 -- and is expected to be faster
 105                 -- `measure` will be executed after func(...)
 106                 local start = time()
 107                 return measure(modname, instrument_name, start, func(...))
 108         end
 109 end
 110
 111 local function can_be_called(func)
 112         -- It has to be a function or callable table
 113         return type(func) == "function" or
 114                 ((type(func) == "table" or type(func) == "userdata") and
 115                 getmetatable(func) and getmetatable(func).__call)
 116 end
 117
 118 local function assert_can_be_called(func, func_name, level)
 119         if not can_be_called(func) then
 120                 -- Then throw an *helpful* error, by pointing on our caller instead of us.
 121                 error(format("Invalid argument to %s. Expected function-like type instead of '%s'.",
 122                                 func_name, type(func)), level + 1)
 123         end
 124 end
 125
 126 ---
 127 -- Wraps a registration function `func` in such a way,
 128 -- that it will automatically instrument any callback function passed as first argument.
 129 --
 130 local function instrument_register(func, func_name)
 131         local register_name = func_name:gsub("^register_", "", 1)
 132         return function(callback, ...)
 133                 assert_can_be_called(callback, func_name, 2)
 134                 register_functions[func_name] = register_functions[func_name] + 1
 135                 return func(instrument {
 136                         func = callback,
 137                         func_name = register_name
 138                 }, ...)
 139         end
 140 end
 141
 142 local function init_chatcommand()
 143         if get_bool_default("instrument.chatcommand", true) then
 144                 local orig_register_chatcommand = core.register_chatcommand
 145                 core.register_chatcommand = function(cmd, def)
 146                         def.func = instrument {
 147                                 func = def.func,
 148                                 label = "/" .. cmd,
 149                         }
 150                         orig_register_chatcommand(cmd, def)
 151                 end
 152         end
 153 end
 154
 155 ---
 156 -- Start instrumenting selected functions
 157 --
 158 local function init()
 159         if get_bool_default("instrument.entity", true) then
 160                 -- Explicitly declare entity api-methods.
 161                 -- Simple iteration would ignore lookup via __index.
 162                 local entity_instrumentation = {
 163                         "on_activate",
 164                         "on_deactivate",
 165                         "on_step",
 166                         "on_punch",
 167                         "on_rightclick",
 168                         "get_staticdata",
 169                 }
 170                 -- Wrap register_entity() to instrument them on registration.
 171                 local orig_register_entity = core.register_entity
 172                 core.register_entity = function(name, prototype)
 173                         local modname = get_current_modname()
 174                         for _, func_name in pairs(entity_instrumentation) do
 175                                 prototype[func_name] = instrument {
 176                                         func = prototype[func_name],
 177                                         mod = modname,
 178                                         func_name = func_name,
 179                                         label = prototype.label,
 180                                 }
 181                         end
 182                         orig_register_entity(name,prototype)
 183                 end
 184         end
 185
 186         if get_bool_default("instrument.abm", true) then
 187                 -- Wrap register_abm() to automatically instrument abms.
 188                 local orig_register_abm = core.register_abm
 189                 core.register_abm = function(spec)
 190                         spec.action = instrument {
 191                                 func = spec.action,
 192                                 class = "ABM",
 193                                 label = spec.label,
 194                         }
 195                         orig_register_abm(spec)
 196                 end
 197         end
 198
 199         if get_bool_default("instrument.lbm", true) then
 200                 -- Wrap register_lbm() to automatically instrument lbms.
 201                 local orig_register_lbm = core.register_lbm
 202                 core.register_lbm = function(spec)
 203                         spec.action = instrument {
 204                                 func = spec.action,
 205                                 class = "LBM",
 206                                 label = spec.label or spec.name,
 207                         }
 208                         orig_register_lbm(spec)
 209                 end
 210         end
 211
 212         if get_bool_default("instrument.global_callback", true) then
 213                 for func_name, _ in pairs(register_functions) do
 214                         core[func_name] = instrument_register(core[func_name], func_name)
 215                 end
 216         end
 217
 218         if get_bool_default("instrument.profiler", false) then
 219                 -- Measure overhead of instrumentation, but keep it down for functions
 220                 -- So keep the `return` for better optimization.
 221                 profiler.empty_instrument = instrument {
 222                         func = function() return end,
 223                         mod = "*profiler*",
 224                         class = "Instrumentation overhead",
 225                         label = false,
 226                 }
 227         end
 228 end
 229
 230 return {
 231         register_functions = register_functions,
 232         instrument = instrument,
 233         init = init,
 234         init_chatcommand = init_chatcommand,
 235 }