Add CPU and memory usage to the performance metrics overlay

Core/NativeClient/Interface/PerformanceMetricsOverlay.lua

@@ -5,6 +5,7 @@ local tinsert = table.insert
 
 local PerformanceMetricsOverlay = {
 	samples = {},
+	formatOverrides = {},
 	isEnabled = false,
 	messageStrings = {
 		NO_SAMPLES_AVAILABLE = "No performance metrics available at this time",
@@ -53,10 +54,33 @@ function PerformanceMetricsOverlay:GetFormattedMetricsString()
 
 		local isLastMetric = (index == #self.samples)
 		local separator = isLastMetric and "" or " | "
-		tinsert(sampleStrings, format("%s: %.2f ms%s", name, avg, separator))
+		local formatString = self.formatOverrides[name] or "%s: %.2f ms%s"
+		tinsert(sampleStrings, format(formatString, name, avg, separator))
 	end
 
 	return tconcat(sampleStrings, "")
 end
 
+local function toMicroseconds(time)
+	return time.sec * 1E6 + time.usec
+end
+
+function PerformanceMetricsOverlay:ComputeResourceUsageForInterval(
+	initialResourceUsage,
+	finalUsage,
+	measuredIntervalInMilliseconds
+)
+	if measuredIntervalInMilliseconds <= 0 then
+		return 0
+	end
+
+	local initialTotal = toMicroseconds(initialResourceUsage.utime)
+	local finalTotal = toMicroseconds(finalUsage.utime)
+
+	local cpuTimeUsedInMicroseconds = finalTotal - initialTotal
+	local elapsedTimeInMicroseconds = measuredIntervalInMilliseconds * 1E3
+
+	return (cpuTimeUsedInMicroseconds / elapsedTimeInMicroseconds) * 100
+end
+
 return PerformanceMetricsOverlay

Core/NativeClient/NativeClient.lua

@@ -87,7 +87,10 @@ function NativeClient:CreateMainWindow()
 end
 
 function NativeClient:StartRenderLoop()
+	PerformanceMetricsOverlay.formatOverrides.CPU = "%s: %.2f %%%s"
+	PerformanceMetricsOverlay.formatOverrides.Memory = "%s: %d MB%s"
 	PerformanceMetricsOverlay:StartMeasuring()
+	local initialResourceUsage = uv.getrusage()
 
 	-- Should probably replace with RML data binding or a similar approach later?
 	self.fpsDisplayTicker = C_Timer.NewTicker(2500, function()
@@ -115,14 +118,27 @@ function NativeClient:StartRenderLoop()
 		local frameEndTime = uv.hrtime()
 
 		local frameTimeInMilliseconds = (frameEndTime - frameStartTime) / 10E5
+		local lastMeasuredResourceUsage = uv.getrusage()
+
+		local cpuUsage = PerformanceMetricsOverlay:ComputeResourceUsageForInterval(
+			initialResourceUsage,
+			lastMeasuredResourceUsage,
+			frameTimeInMilliseconds
+		)
+		initialResourceUsage = lastMeasuredResourceUsage
+
 		local sample = {
+			CPU = cpuUsage,
+			Memory = collectgarbage("count") / 1024,
 			Frame = frameTimeInMilliseconds,
 			Render = cpuFrameTime / 10E5,
 			World = worldRenderTime / 10E5,
 			UI = uiRenderTime / 10E5,
 			Submit = commandSubmissionTime / 10E5,
 			UV = uvPollingTime / 10E5,
 			GLFW = (glfwPollingTime + replayTime) / 10E5,
+			"Memory",
+			"CPU",
 			"Frame",
 			"Render",
 			"World",

Tests/NativeClient/Interface/PerformanceMetricsOverlay.spec.lua

@@ -90,5 +90,102 @@ describe("PerformanceMetricsOverlay", function()
 				"totalFrameTime: 100.00 ms | cpuRenderTime: nan ms | worldRenderTime: 200.00 ms | interfaceRenderTime: 300.00 ms | commandSubmissionTime: 600.00 ms | uvPollingTime: 400.00 ms | glfwPollingTime: 500.00 ms"
 			assertEquals(actual, expected)
 		end)
+
+		it("should allow overriding the format for non-standard types of metrics", function()
+			PerformanceMetricsOverlay:StartMeasuring()
+
+			local metricsEntry = {
+				Memory = 1024,
+				Percentage = 56.75345,
+				Time = 250,
+				"Memory",
+				"Percentage",
+				"Time",
+			}
+			PerformanceMetricsOverlay:AddSample(metricsEntry)
+			PerformanceMetricsOverlay:AddSample(metricsEntry)
+
+			PerformanceMetricsOverlay.formatOverrides.Memory = "%s: %d MB%s"
+			PerformanceMetricsOverlay.formatOverrides.Percentage = "%s: %.2f %%%s"
+			PerformanceMetricsOverlay.formatOverrides.Time = "%s: %d milliseconds%s"
+
+			local actual = PerformanceMetricsOverlay:GetFormattedMetricsString()
+			local expected = "Memory: 1024 MB | Percentage: 56.75 % | Time: 250 milliseconds"
+			assertEquals(actual, expected)
+		end)
+
+		describe("ComputeResourceUsageForInterval", function()
+			local function uvMakeResourceUsage(seconds, microseconds)
+				return {
+					utime = { sec = seconds, usec = microseconds },
+					stime = { sec = 0, usec = 0 }, -- stime is ignored since it may be async background tasks etc.
+				}
+			end
+
+			it("should compute the resource usage if the measured interval is zero", function()
+				local initialUsage = uvMakeResourceUsage(1, 500000) -- 1.5 seconds
+				local finalUsage = uvMakeResourceUsage(1, 500000) -- 1.5 seconds
+				local measuredIntervalInMilliseconds = 0 -- 1 second
+				local expected = 0
+				local actual = PerformanceMetricsOverlay:ComputeResourceUsageForInterval(
+					initialUsage,
+					finalUsage,
+					measuredIntervalInMilliseconds
+				)
+				assertEquals(actual, expected)
+			end)
+
+			it("should compute the resource usage correctly if it's 0%", function()
+				local initialUsage = uvMakeResourceUsage(1, 500000) -- 1.5 seconds
+				local finalUsage = uvMakeResourceUsage(1, 500000) -- 1.5 seconds
+				local measuredIntervalInMilliseconds = 1000 -- 1 second
+				local expected = 0
+				local actual = PerformanceMetricsOverlay:ComputeResourceUsageForInterval(
+					initialUsage,
+					finalUsage,
+					measuredIntervalInMilliseconds
+				)
+				assertEquals(actual, expected)
+			end)
+
+			it("should compute the resource usage correctly if it's 100%", function()
+				local initialUsage = uvMakeResourceUsage(0, 500000) -- 0.5 seconds
+				local finalUsage = uvMakeResourceUsage(1, 0) -- 1 second
+				local measuredIntervalInMilliseconds = 500 -- 0.5 second
+				local expected = 100 -- 100% CPU usage
+				local actual = PerformanceMetricsOverlay:ComputeResourceUsageForInterval(
+					initialUsage,
+					finalUsage,
+					measuredIntervalInMilliseconds
+				)
+				assertEquals(actual, expected)
+			end)
+
+			it("should compute the resource usage correctly if it's more than 100%", function()
+				local initialUsage = uvMakeResourceUsage(0, 500000) -- 0.5 seconds
+				local finalUsage = uvMakeResourceUsage(2, 0) -- 1 second
+				local measuredIntervalInMilliseconds = 500 -- 0.5 second
+				local expected = 300 -- 300% CPU usage (probably a measurement error or timer inaccuracy - ignore it)
+				local actual = PerformanceMetricsOverlay:ComputeResourceUsageForInterval(
+					initialUsage,
+					finalUsage,
+					measuredIntervalInMilliseconds
+				)
+				assertEquals(actual, expected)
+			end)
+
+			it("should compute the resource usage correctly over the provided duration", function()
+				local initialUsage = uvMakeResourceUsage(1, 0) -- 1 second
+				local finalUsage = uvMakeResourceUsage(2, 0) -- 2 seconds
+				local measuredIntervalInMilliseconds = 2000 -- 2 seconds
+				local expected = 50 -- 50% CPU usage
+				local actual = PerformanceMetricsOverlay:ComputeResourceUsageForInterval(
+					initialUsage,
+					finalUsage,
+					measuredIntervalInMilliseconds
+				)
+				assertEquals(actual, expected)
+			end)
+		end)
 	end)
 end)