improved stability of cpu usage calculation

firmware/application/CMakeLists.txt

@@ -155,6 +155,7 @@ set(CPPSRC
 	${COMMON}/ui_widget.cpp
 	${COMMON}/utility.cpp
 	${COMMON}/wm8731.cpp
+	${COMMON}/performance_counter.cpp
 	app_settings.cpp
 	audio.cpp
 	baseband_api.cpp

firmware/application/apps/ui_dfu_menu.cpp

@@ -21,6 +21,7 @@
 
 #include "ui_dfu_menu.hpp"
 #include "portapack_shared_memory.hpp"
+#include "performance_counter.hpp"
 
 namespace ui {
 
@@ -39,21 +40,11 @@ DfuMenu::DfuMenu(NavigationView& nav) : nav_ (nav) {
 }
 
 void DfuMenu::paint(Painter& painter) {
-	auto now = chTimeNow();
+	auto utilisation = get_cpu_utilisation_in_percent();
-	auto idle_ticks = chThdGetTicks(chSysGetIdleThread());
-	
-	static systime_t last_time;
-	static systime_t last_last_time;
-
-	auto time_elapsed = now - last_time;
-	auto idle_elapsed = idle_ticks - last_last_time;
-
-	last_time = now;
-	last_last_time = idle_ticks;
 
 	text_info_line_1.set(to_string_dec_uint(chCoreStatus(), 6));
 	text_info_line_2.set(to_string_dec_uint((uint32_t)get_free_stack_space(), 6));
-	text_info_line_3.set(to_string_dec_uint((time_elapsed - idle_elapsed) / 10, 6));
+	text_info_line_3.set(to_string_dec_uint(utilisation, 6));
 	text_info_line_4.set(to_string_dec_uint(shared_memory.m4_heap_usage, 6));
 	text_info_line_5.set(to_string_dec_uint(shared_memory.m4_stack_usage, 6));
 	text_info_line_6.set(to_string_dec_uint(shared_memory.m4_cpu_usage, 6));

firmware/baseband/CMakeLists.txt

@@ -139,6 +139,7 @@ set(CPPSRC
 	${COMMON}/chibios_cpp.cpp
 	debug.cpp
 	${COMMON}/gcc.cpp
+	${COMMON}/performance_counter.cpp
 	tone_gen.cpp
 )
 

firmware/baseband/debug.cpp

@@ -26,6 +26,7 @@
 #include <hal.h>
 
 #include "portapack_shared_memory.hpp"
+#include "performance_counter.hpp"
 
 void write_m4_panic_msg(const char *panic_message, struct extctx *ctxp) {
     if (ctxp == nullptr) {
@@ -120,29 +121,25 @@ void update_performance_counters() {
 	auto performance_counter_active = shared_memory.request_m4_performance_counter;
 	if (performance_counter_active == 0x00)
 		return;
+
 	static bool last_paint_state = false;
 	if ((((chTimeNow()>>10) & 0x01) == 0x01) == last_paint_state)
 		return;
 
+    volatile auto idle_thread = chSysGetIdleThread();
+   	if (chThdGetTicks(idle_thread) > 0x10000000) {
+        return;
+    }
+
+    idle_thread = nullptr;
+
 	last_paint_state = !last_paint_state;
 
-	auto now = chTimeNow();
+	auto utilisation = get_cpu_utilisation_in_percent();
-	auto idle_ticks = chThdGetTicks(chSysGetIdleThread());
-	
-	static systime_t last_time;
-	static systime_t last_last_time;
-
-	auto time_elapsed = now - last_time;
-	auto idle_elapsed = idle_ticks - last_last_time;
-
-	last_time = now;
-	last_last_time = idle_ticks;
-
-	auto cpu_usage = (time_elapsed - idle_elapsed) / 10;
 	auto free_stack = (uint32_t)get_free_stack_space();
 	auto free_heap = chCoreStatus();
 
-	shared_memory.m4_cpu_usage = cpu_usage;
+	shared_memory.m4_cpu_usage = utilisation;
 	shared_memory.m4_stack_usage = free_stack;
 	shared_memory.m4_heap_usage = free_heap;
 }

firmware/common/performance_counter.cpp

@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2023 Bernd Herzog
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include "performance_counter.hpp"
+#include "ch.h"
+
+uint8_t get_cpu_utilisation_in_percent() {
+	static systime_t last_time = 0;
+	static systime_t last_idle_ticks = 0;
+
+	auto now = chTimeNow();
+	auto idle_ticks = chThdGetTicks(chSysGetIdleThread());
+
+	if (last_time == 0) {
+		last_time = now;
+		last_idle_ticks = idle_ticks;
+
+		return 0;
+	}
+
+	int32_t time_elapsed = now - last_time;
+	int32_t idle_elapsed = idle_ticks - last_idle_ticks;
+
+	int32_t working_ticks = time_elapsed - idle_elapsed;
+
+	if (working_ticks < 0)
+		working_ticks = 0;
+
+	auto utilisation = working_ticks * 100 / time_elapsed;
+
+	last_time = now;
+	last_idle_ticks = idle_ticks;
+
+	if (utilisation > 100) {
+		return 100;
+	}
+
+    return (uint8_t) utilisation;
+}

firmware/common/performance_counter.hpp

@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2023 Bernd Herzog
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __PERFORMANCE_COUNTER_H__
+#define __PERFORMANCE_COUNTER_H__
+
+#include <stdint.h>
+
+uint8_t get_cpu_utilisation_in_percent();
+
+#endif /* __PERFORMANCE_COUNTER_H__ */