Builtin/profiler: Replace game profiler (#4245)

Use the setting "profiler.load" to enable profiling.
Other settings can be found in settingtypes.txt.

* /profiler print [filter] - report statistics to in-game console
* /profiler dump [filter] - report statistics to STDOUT and debug.txt
* /profiler save [format [filter]] - saves statistics to a file in your worldpath
	* txt (default) - same treetable format as used by the dump and print commands
	* csv - ready for spreadsheet import
	* json - useful for adhoc D3 visualizations
	* json_pretty - line wrapped and intended json for humans
	* lua - serialized lua table of the profile-data, for adhoc scripts
* /profiler reset - reset all gathered profile data.
	This can be helpful to discard of any startup measurements that often spike during loading or to get more useful min-values.

[filter] allows limiting the output of the data via substring/pattern matching against the modname.

Note: Serialized data structures might be subject to change with changed or added measurements.
	csv might be the most stable, due to flat structure.

Changes to the previous version include:

* Updated and extended API monitoring
* Correct calculation of average (mean) values (undistorted by idleness)
* Reduce instrumentation overhead.
* Fix crashes related to missing parameters for the future and occasional DIV/0's.
* Prevent issues caused by timetravel (overflow, timejump, NTP corrections)
* Prevent modname clashes with internal names.
* Measure each instrumentation individually and label based on registration order.
* Labeling of ABM's and LBM's for easier classification.
  Giving several ABM's or LBM's the same label will treat them as one.
  Missing labels will be autogenerated based on name or registration order.
* Configurable instrumentation and reporting. Skip e.g. builtin if you don't need it.
* Profile the profiler to measure instrumentation overhead.

1 files changed, 72 insertions, 0 deletions

diff --git a/builtin/profiler/init.lua b/builtin/profiler/init.lua
new file mode 100644
index 000000000..c1597d280
--- /dev/null
+++ b/builtin/profiler/init.lua
@@ -0,0 +1,72 @@
+--Minetest
+--Copyright (C) 2016 T4im
+--
+--This program is free software; you can redistribute it and/or modify
+--it under the terms of the GNU Lesser General Public License as published by
+--the Free Software Foundation; either version 2.1 of the License, or
+--(at your option) any later version.
+--
+--This program is distributed in the hope that it will be useful,
+--but WITHOUT ANY WARRANTY; without even the implied warranty of
+--MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+--GNU Lesser General Public License for more details.
+--
+--You should have received a copy of the GNU Lesser General Public License along
+--with this program; if not, write to the Free Software Foundation, Inc.,
+--51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+local profiler_path = core.get_builtin_path()..DIR_DELIM.."profiler"..DIR_DELIM
+local profiler = {}
+local sampler = assert(loadfile(profiler_path .. "sampling.lua"))(profiler)
+local instrumentation  = assert(loadfile(profiler_path .. "instrumentation.lua"))(profiler, sampler)
+local reporter = dofile(profiler_path .. "reporter.lua")
+profiler.instrument = instrumentation.instrument
+
+---
+-- Delayed registration of the /profiler chat command
+-- Is called later, after `core.register_chatcommand` was set up.
+--
+function profiler.init_chatcommand()
+	local instrument_profiler = core.setting_getbool("instrument.profiler") or false
+	if instrument_profiler then
+		instrumentation.init_chatcommand()
+	end
+
+	local param_usage = "print [filter] | dump [filter] | save [format [filter]] | reset"
+	core.register_chatcommand("profiler", {
+		description = "handle the profiler and profiling data",
+		params = param_usage,
+		privs = { server=true },
+		func = function(name, param)
+			local command, arg0 = string.match(param, "([^ ]+) ?(.*)")
+			local args = arg0 and string.split(arg0, " ")
+
+			if command == "dump" then
+				core.log("action", reporter.print(sampler.profile, arg0))
+				return true, "Statistics written to action log"
+			elseif command == "print" then
+				return true, reporter.print(sampler.profile, arg0)
+			elseif command == "save" then
+				return reporter.save(sampler.profile, args[1] or "txt", args[2])
+			elseif command == "reset" then
+				sampler.reset()
+				return true, "Statistics were reset"
+			end
+
+			return false, string.format(
+				"Usage: %s\n" ..
+				"Format can be one of txt, csv, lua, json, json_pretty (structures may be subject to change).",
+				param_usage
+			)
+		end
+	})
+
+	if not instrument_profiler then
+		instrumentation.init_chatcommand()
+	end
+end
+
+sampler.init()
+instrumentation.init()
+
+return profiler