From 0094a1ee988d12117c1d70968df751b7a7200382 Mon Sep 17 00:00:00 2001
From: Alexis Murzeau <amubtdx@gmail.com>
Date: Thu, 22 Aug 2024 15:55:13 +0200
Subject: [PATCH] damc: cpufreq: ignore first measure after changing frequency

The measure cause bouncing between frequencies.
---
 damc/damc_simple_lib/CPUFrequencyScaling.cpp | 8 ++++++++
 damc/damc_simple_lib/CPUFrequencyScaling.h   | 1 +
 2 files changed, 9 insertions(+)

diff --git a/damc/damc_simple_lib/CPUFrequencyScaling.cpp b/damc/damc_simple_lib/CPUFrequencyScaling.cpp
index a838b11..2e54b70 100644
--- a/damc/damc_simple_lib/CPUFrequencyScaling.cpp
+++ b/damc/damc_simple_lib/CPUFrequencyScaling.cpp
@@ -41,6 +41,7 @@ CPUFrequencyScaling::CPUFrequencyScaling(OscRoot* oscRoot)
       oscRoot(oscRoot),
       oscCurrentFrequency(this, "freq", SystemCoreClock),
       current_ahb_divider(1),
+      recent_ahb_divider_change(false),
       max_cpu_usage_ratio_per_million(0),
       cpu_usage_points(0),
       cpu_usage_points_target(0) {
@@ -63,6 +64,12 @@ void CPUFrequencyScaling::resetFrequencyToMaxPerformance() {
 }
 
 void CPUFrequencyScaling::notifyCurrentCpuUsage(uint32_t cpu_usage_ratio_per_million) {
+	// Skip first measure after a frequency change
+	if(recent_ahb_divider_change) {
+		recent_ahb_divider_change = false;
+		return;
+	}
+
 	cpu_usage_points++;
 	if(cpu_usage_ratio_per_million > max_cpu_usage_ratio_per_million) {
 		max_cpu_usage_ratio_per_million = cpu_usage_ratio_per_million;
@@ -120,6 +127,7 @@ uint32_t CPUFrequencyScaling::setAHBDivider(uint32_t divider) {
 	HAL_InitTick(TICK_INT_PRIORITY);
 
 	current_ahb_divider = ahb_divider;
+	recent_ahb_divider_change = true;
 
 	// Reset cpu usage stats
 	cpu_usage_points = 0;
diff --git a/damc/damc_simple_lib/CPUFrequencyScaling.h b/damc/damc_simple_lib/CPUFrequencyScaling.h
index 5783862..3fc8110 100644
--- a/damc/damc_simple_lib/CPUFrequencyScaling.h
+++ b/damc/damc_simple_lib/CPUFrequencyScaling.h
@@ -21,6 +21,7 @@ class CPUFrequencyScaling : public OscContainer {
 	OscRoot* oscRoot;
 	OscReadOnlyVariable<int32_t> oscCurrentFrequency;
 	uint32_t current_ahb_divider;
+	bool recent_ahb_divider_change;
 
 	uint32_t max_cpu_usage_ratio_per_million;
 	uint32_t cpu_usage_points;