Fix: Data race with mixer thread performance measurements

pull/453/head
Jonathan G Rennison 2 years ago committed by Michael Lutz
parent 0fae0599b7
commit 64b437fa89

@ -25,8 +25,16 @@
#include "game/game_instance.hpp"
#include "widgets/framerate_widget.h"
#include <atomic>
#include <mutex>
#include <vector>
#include "safeguards.h"
static std::mutex _sound_perf_lock;
static std::atomic<bool> _sound_perf_pending;
static std::vector<TimingMeasurement> _sound_perf_measurements;
/**
* Private declarations for performance measurement implementation
@ -251,6 +259,20 @@ PerformanceMeasurer::~PerformanceMeasurer()
return;
}
}
if (this->elem == PFE_SOUND) {
/* PFE_SOUND measurements are made from the mixer thread.
* _pf_data cannot be concurrently accessed from the mixer thread
* and the main thread, so store the measurement results in a
* mutex-protected queue which is drained by the main thread.
* See: ProcessPendingPerformanceMeasurements() */
TimingMeasurement end = GetPerformanceTimer();
std::lock_guard lk(_sound_perf_lock);
if (_sound_perf_measurements.size() >= NUM_FRAMERATE_POINTS * 2) return;
_sound_perf_measurements.push_back(this->start_time);
_sound_perf_measurements.push_back(end);
_sound_perf_pending.store(true, std::memory_order_release);
return;
}
_pf_data[this->elem].Add(this->start_time, GetPerformanceTimer());
}
@ -1079,3 +1101,22 @@ void ConPrintFramerate()
IConsolePrint(CC_ERROR, "No performance measurements have been taken yet.");
}
}
/**
* This drains the PFE_SOUND measurement data queue into _pf_data.
* PFE_SOUND measurements are made by the mixer thread and so cannot be stored
* into _pf_data directly, because this would not be thread safe and would violate
* the invariants of the FPS and frame graph windows.
* @see PerformanceMeasurement::~PerformanceMeasurement()
*/
void ProcessPendingPerformanceMeasurements()
{
if (_sound_perf_pending.load(std::memory_order_acquire)) {
std::lock_guard lk(_sound_perf_lock);
for (size_t i = 0; i < _sound_perf_measurements.size(); i += 2) {
_pf_data[PFE_SOUND].Add(_sound_perf_measurements[i], _sound_perf_measurements[i + 1]);
}
_sound_perf_measurements.clear();
_sound_perf_pending.store(false, std::memory_order_relaxed);
}
}

@ -3067,6 +3067,9 @@ void UpdateWindows()
PerformanceMeasurer framerate(PFE_DRAWING);
PerformanceAccumulator::Reset(PFE_DRAWWORLD);
extern void ProcessPendingPerformanceMeasurements();
ProcessPendingPerformanceMeasurements();
CallWindowRealtimeTickEvent(delta_ms);
static GUITimer network_message_timer = GUITimer(1);

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