Add UI thread CPU meter.

include/system.hpp

@@ -162,6 +162,7 @@ double getTime();
 /** Returns time since 1970-01-01 00:00:00 UTC in seconds.
 */
 double getUnixTime();
+double getThreadTime();
 std::string getOperatingSystemInfo();
 
 // Applications

src/app/MenuBar.cpp

@@ -808,6 +808,9 @@ struct MeterLabel : ui::Label {
 	int frameIndex = 0;
 	double frameDurationTotal = 0.0;
 	double frameDurationAvg = 0.0;
+	double uiLastTime = 0.0;
+	double uiLastThreadTime = 0.0;
+	double uiFrac = 0.0;
 
 	void step() override {
 		// Compute frame rate
@@ -820,9 +823,19 @@ struct MeterLabel : ui::Label {
 			frameIndex = 0;
 		}
 
+		// Compute UI thread CPU
+		double time = system::getTime();
+		double uiDuration = time - uiLastTime;
+		if (uiDuration >= 1.0) {
+			double threadTime = system::getThreadTime();
+			uiFrac = (threadTime - uiLastThreadTime) / uiDuration;
+			uiLastThreadTime = threadTime;
+			uiLastTime = time;
+		}
+
 		double meterAverage = APP->engine->getMeterAverage();
 		double meterMax = APP->engine->getMeterMax();
-		text = string::f("%.1f fps  %.1f%% avg  %.1f%% max", 1.0 / frameDurationAvg, meterAverage * 100, meterMax * 100);
+		text = string::f("%.1f fps  %.1f%% avg  %.1f%% max  %.1f%% UI", 1.0 / frameDurationAvg, meterAverage * 100, meterMax * 100, uiFrac * 100);
 		Label::step();
 	}
 };

src/system.cpp

@@ -695,6 +695,27 @@ double getUnixTime() {
 }
 
 
+double getThreadTime() {
+#if defined ARCH_LIN
+	struct timespec ts;
+	clockid_t cid;
+	pthread_getcpuclockid(pthread_self(), &cid);
+	clock_gettime(cid, &ts);
+	return ts.tv_sec + ts.tv_nsec * 1e-9;
+#elif defined ARCH_MAC
+	mach_port_t thread = mach_thread_self();
+	mach_msg_type_number_t count = THREAD_BASIC_INFO_COUNT;
+	thread_basic_info_data_t info;
+	kern_return_t kr = thread_info(thread, THREAD_BASIC_INFO, (thread_info_t) &info, &count);
+	if (kr != KERN_SUCCESS || (info.flags & TH_FLAGS_IDLE) != 0)
+		return 0.0;
+	return info.user_time.seconds + info.user_time.microseconds * 1e-6;
+#elif defined ARCH_WIN
+	return 0.0;
+#endif
+}
+
+
 std::string getOperatingSystemInfo() {
 #if defined ARCH_LIN || defined ARCH_MAC
 	struct utsname u;