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()
  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 time() and func(...)
 106                 return measure(modname, instrument_name, time(), func(...))
 107         end
 108 end
 109
 110 local function can_be_called(func)
 111         -- It has to be a function or callable table
 112         return type(func) == "function" or
 113                 ((type(func) == "table" or type(func) == "userdata") and
 114                 getmetatable(func) and getmetatable(func).__call)
 115 end
 116
 117 local function assert_can_be_called(func, func_name, level)
 118         if not can_be_called(func) then
 119                 -- Then throw an *helpful* error, by pointing on our caller instead of us.
 120                 error(format("Invalid argument to %s. Expected function-like type instead of '%s'.", func_name, type(func)), level + 1)
 121         end
 122 end
 123
 124 ---
 125 -- Wraps a registration function `func` in such a way,
 126 -- that it will automatically instrument any callback function passed as first argument.
 127 --
 128 local function instrument_register(func, func_name)
 129         local register_name = func_name:gsub("^register_", "", 1)
 130         return function(callback, ...)
 131                 assert_can_be_called(callback, func_name, 2)
 132                 register_functions[func_name] = register_functions[func_name] + 1
 133                 return func(instrument {
 134                         func = callback,
 135                         func_name = register_name
 136                 }), ...
 137         end
 138 end
 139
 140 local function init_chatcommand()
 141         if get_bool_default("instrument.chatcommand", true) then
 142                 local orig_register_chatcommand = core.register_chatcommand
 143                 core.register_chatcommand = function(cmd, def)
 144                         def.func = instrument {
 145                                 func = def.func,
 146                                 label = "/" .. cmd,
 147                         }
 148                         orig_register_chatcommand(cmd, def)
 149                 end
 150         end
 151 end
 152
 153 ---
 154 -- Start instrumenting selected functions
 155 --
 156 local function init()
 157         if get_bool_default("instrument.entity", true) then
 158                 -- Explicitly declare entity api-methods.
 159                 -- Simple iteration would ignore lookup via __index.
 160                 local entity_instrumentation = {
 161                         "on_activate",
 162                         "on_step",
 163                         "on_punch",
 164                         "rightclick",
 165                         "get_staticdata",
 166                 }
 167                 -- Wrap register_entity() to instrument them on registration.
 168                 local orig_register_entity = core.register_entity
 169                 core.register_entity = function(name, prototype)
 170                         local modname = get_current_modname()
 171                         for _, func_name in pairs(entity_instrumentation) do
 172                                 prototype[func_name] = instrument {
 173                                         func = prototype[func_name],
 174                                         mod = modname,
 175                                         func_name = func_name,
 176                                         label = prototype.label,
 177                                 }
 178                         end
 179                         orig_register_entity(name,prototype)
 180                 end
 181         end
 182
 183         if get_bool_default("instrument.abm", true) then
 184                 -- Wrap register_abm() to automatically instrument abms.
 185                 local orig_register_abm = core.register_abm
 186                 core.register_abm = function(spec)
 187                         spec.action = instrument {
 188                                 func = spec.action,
 189                                 class = "ABM",
 190                                 label = spec.label,
 191                         }
 192                         orig_register_abm(spec)
 193                 end
 194         end
 195
 196         if get_bool_default("instrument.lbm", true) then
 197                 -- Wrap register_lbm() to automatically instrument lbms.
 198                 local orig_register_lbm = core.register_lbm
 199                 core.register_lbm = function(spec)
 200                         spec.action = instrument {
 201                                 func = spec.action,
 202                                 class = "LBM",
 203                                 label = spec.label or spec.name,
 204                         }
 205                         orig_register_lbm(spec)
 206                 end
 207         end
 208
 209         if get_bool_default("instrument.global_callback", true) then
 210                 for func_name, _ in pairs(register_functions) do
 211                         core[func_name] = instrument_register(core[func_name], func_name)
 212                 end
 213         end
 214
 215         if get_bool_default("instrument.profiler", false) then
 216                 -- Measure overhead of instrumentation, but keep it down for functions
 217                 -- So keep the `return` for better optimization.
 218                 profiler.empty_instrument = instrument {
 219                         func = function() return end,
 220                         mod = "*profiler*",
 221                         class = "Instrumentation overhead",
 222                         label = false,
 223                 }
 224         end
 225 end
 226
 227 return {
 228         register_functions = register_functions,
 229         instrument = instrument,
 230         init = init,
 231         init_chatcommand = init_chatcommand,
 232 }