add a method for recording and graphing mapgen time

init.lua

@@ -14,6 +14,7 @@ dofile(MP.."/region_functions.lua")
 dofile(MP.."/lines.lua")
 dofile(MP.."/place_schematic.lua")
 dofile(MP.."/noise_manager.lua")
+dofile(MP.."/metrics.lua")
 
 
 local map_data = {}

metrics.lua

@@ -0,0 +1,112 @@
+local worldpath = minetest.get_worldpath()
+
+if not minetest.settings:get_bool("mapgen_helper_record_time", false) then
+	mapgen_helper.record_time = function()
+		return
+	end
+end
+
+local persist = minetest.settings:get_bool("mapgen_helper_persist_recorded_time", false)
+local filename = "mapgen_helper_metrics.lua"
+local filename_old = "mapgen_helper_metrics_old.lua"
+
+local resolution = minetest.settings:get("mapgen_helper_record_time_resolution") or 0.1
+
+local data = {}
+data.times = {}
+
+if persist then
+	local read_data = loadfile(worldpath.."/"..filename)
+	if read_data then
+		data = read_data()
+	end	
+end
+
+if data.resolution ~= nil and data.resolution ~= resolution then
+	minetest.log("error", "[mapgen_helper] resolution of recorded metrics doesn't match saved metrics. Moving the old saved metrics to " .. filename_old)
+	local file, e = io.open(worldpath.."/"..filename_old, "w");
+	if not file then
+		return error(e);
+	end
+	file:write(minetest.serialize(data))
+	file:close()
+	data = {}
+	data.times = {}
+end
+
+data.resolution = resolution
+local times = data.times
+
+mapgen_helper.record_time = function(label, time)
+	local time_slot = math.ceil(time/resolution)
+	local label_data = times[label] or {}
+	local counts = label_data.counts or {}
+	local existing_count = counts[time_slot] or 0
+	local total_time = label_data.total_time or 0
+
+	counts[time_slot] = existing_count + 1
+	total_time = total_time + time
+	label_data.total_time = total_time
+	label_data.counts = counts
+	times[label] = label_data
+end
+
+minetest.register_on_shutdown(function()
+	if next(times) == nil then
+		return
+	end	
+	minetest.log("warning", "[mapgen_helper] Average chunk generation times:")
+	for name, label_data in pairs(times) do
+		minetest.log("warning", string.rep("-", 40))
+
+		local min_slot
+		local max_slot
+		local highest_slot_count = 0
+		local total_count = 0
+		local max_digits
+
+		for slot, count in pairs(label_data.counts) do
+			if (not min_slot) or (slot < min_slot) then
+				min_slot = slot
+			end
+			if (not max_slot) or (slot > max_slot) then
+				max_slot = slot
+			end
+			if (not max_digits) or (#tostring(slot*resolution) > max_digits) then
+				max_digits = #tostring(slot*resolution)
+			end
+			total_count = total_count + count
+			highest_slot_count = math.max(highest_slot_count, count)			
+		end
+
+		local average = label_data.total_time / total_count
+
+		minetest.log("warning", "For " .. name .. ":")
+		if min_slot == max_slot then
+			minetest.log("warning", "All chunks took between " .. (min_slot-1)*resolution .. " and " .. min_slot*resolution .. " seconds.")
+		else
+			for i = min_slot, max_slot do
+				local count = label_data.counts[i] or 0
+				local spacing = max_digits - #tostring(i*resolution)
+				local count_string = ""
+				if count > 0 then
+					count_string = " " .. count
+				end
+				minetest.log("warning", i*resolution .. "s" .. string.rep(" ", spacing) .. ": " ..
+					string.rep("=", math.ceil((count / highest_slot_count) * 40)) .. count_string)
+			end
+		end
+
+		minetest.log("warning", "Total number of chunks: " .. total_count .. ". Average time per chunk: " .. average .. " seconds.")
+	end
+	minetest.log("warning", string.rep("-", 40))
+
+	if persist then
+		local file, e = io.open(worldpath.."/"..filename, "w");
+		if not file then
+			return error(e);
+		end
+		file:write(minetest.serialize(data))
+		file:close()
+	end
+end)

settingtypes.txt

@@ -0,0 +1,3 @@
+mapgen_helper_record_time (Enable time-taken logging) bool false
+mapgen_helper_persist_recorded_time (Persist time-taken logging between server sessions) bool false
+mapgen_helper_record_time_resolution (Resolution of time-taken histogram) float 0.1