kernel/scheduler: enable cpu load tracking after boot

when the cpufreq module is loaded, we let the scheduler update its policy.
Improve assert report
CoreEntry::GetLoad() could return more than kMaxLoad.

Change-Id: I127f9b3e8062b5996872aae30b4021b9904fa179
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3216
Reviewed-by: Jérôme Duval <[email protected]>

headers/private/kernel/kscheduler.h

@@ -86,6 +86,7 @@ void scheduler_remove_listener(struct SchedulerListener* listener);
 
 void scheduler_init(void);
 void scheduler_enable_scheduling(void);
+void scheduler_update_policy(void);
 
 bigtime_t _user_estimate_max_scheduling_latency(thread_id thread);
 status_t _user_analyze_scheduling(bigtime_t from, bigtime_t until, void* buffer,

src/system/kernel/cpu.cpp

@@ -89,6 +89,8 @@ load_cpufreq_module()
 
 	if (sCPUPerformanceModule == NULL)
 		dprintf("no valid cpufreq module found\n");
+	else
+		scheduler_update_policy();
 }
 
 

src/system/kernel/scheduler/scheduler.cpp

@@ -654,12 +654,7 @@ init()
 
 	// disable parts of the scheduler logic that are not needed
 	gSingleCore = coreCount == 1;
-	gTrackCPULoad = increase_cpu_performance(0) == B_OK;
+	scheduler_update_policy();
-	gTrackCoreLoad = !gSingleCore || gTrackCPULoad;
-	dprintf("scheduler switches: single core: %s, cpu load tracking: %s,"
-		" core load tracking: %s\n", gSingleCore ? "true" : "false",
-		gTrackCPULoad ? "true" : "false",
-		gTrackCoreLoad ? "true" : "false");
 
 	gCoreCount = coreCount;
 	gPackageCount = packageCount;
@@ -740,6 +735,18 @@ scheduler_enable_scheduling()
 }
 
 
+void
+scheduler_update_policy()
+{
+	gTrackCPULoad = increase_cpu_performance(0) == B_OK;
+	gTrackCoreLoad = !gSingleCore || gTrackCPULoad;
+	dprintf("scheduler switches: single core: %s, cpu load tracking: %s,"
+		" core load tracking: %s\n", gSingleCore ? "true" : "false",
+		gTrackCPULoad ? "true" : "false",
+		gTrackCoreLoad ? "true" : "false");
+}
+
+
 // #pragma mark - SchedulerListener
 
 

src/system/kernel/scheduler/scheduler_cpu.cpp

@@ -326,7 +326,9 @@ CPUEntry::_RequestPerformanceLevel(ThreadData* threadData)
 	}
 
 	int32 load = std::max(threadData->GetLoad(), fCore->GetLoad());
-	ASSERT(load >= 0 && load <= kMaxLoad);
+	ASSERT_PRINT(load >= 0 && load <= kMaxLoad, "load is out of range %"
+		B_PRId32 " (max of %" B_PRId32 " %" B_PRId32 ")", load,
+		threadData->GetLoad(), fCore->GetLoad());
 
 	if (load < kTargetLoad) {
 		int32 delta = kTargetLoad - load;

src/system/kernel/scheduler/scheduler_cpu.h

@@ -397,7 +397,7 @@ CoreEntry::GetLoad() const
 	SCHEDULER_ENTER_FUNCTION();
 
 	ASSERT(fCPUCount > 0);
-	return fLoad / fCPUCount;
+	return std::min(fLoad / fCPUCount, kMaxLoad);
 }