From e938d4936fc36e278b05dab2850edfbbd3e044fa Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Mon, 5 Jun 2023 01:42:24 +0200
Subject: [PATCH] Further speed up Windows freewheel export

---
 libs/backends/portaudio/portaudio_backend.cc | 10 +++++++++-
 libs/backends/portaudio/portaudio_backend.h  |  1 +
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/libs/backends/portaudio/portaudio_backend.cc b/libs/backends/portaudio/portaudio_backend.cc
index 4a4ed2580d..82d38f0a6e 100644
--- a/libs/backends/portaudio/portaudio_backend.cc
+++ b/libs/backends/portaudio/portaudio_backend.cc
@@ -75,6 +75,7 @@ PortAudioBackend::PortAudioBackend (AudioEngine& e, AudioBackendInfo& info)
 	, _freewheel_ack (false)
 	, _reinit_thread_callback (false)
 	, _measure_latency (false)
+	, _freewheel_processed (0)
 	, _cycle_count(0)
 	, _total_deviation_us(0)
 	, _max_deviation_us(0)
@@ -949,6 +950,7 @@ PortAudioBackend::freewheel_process_thread()
 			// tell the engine we're ready to GO.
 			engine.freewheel_callback (_freewheeling);
 			first_run = false;
+			_freewheel_processed = 0;
 			_main_thread = pthread_self();
 			AudioEngine::thread_init_callback (this);
 			_midiio->set_enabled(false);
@@ -1487,6 +1489,8 @@ PortAudioBackend::blocking_process_thread ()
 			engine.freewheel_callback (_freewheel);
 			if (!_freewheel) {
 				_dsp_calc.reset ();
+			} else {
+				_freewheel_processed = 0;
 			}
 		}
 
@@ -1663,7 +1667,11 @@ PortAudioBackend::blocking_process_freewheel()
 	}
 
 	_dsp_load = 1.0;
-	Glib::usleep(100); // don't hog cpu
+	_freewheel_processed += _samples_per_period;
+	if (_freewheel_processed > _samplerate) {
+		_freewheel_processed = 0;
+		Glib::usleep(100); // don't hog cpu
+	}
 	return true;
 }
 
diff --git a/libs/backends/portaudio/portaudio_backend.h b/libs/backends/portaudio/portaudio_backend.h
index 60babf74c3..643e21294a 100644
--- a/libs/backends/portaudio/portaudio_backend.h
+++ b/libs/backends/portaudio/portaudio_backend.h
@@ -298,6 +298,7 @@ class PortAudioBackend : public AudioBackend, public PortEngineSharedImpl {
 		bool  _freewheel_ack;
 		bool  _reinit_thread_callback;
 		bool  _measure_latency;
+		int   _freewheel_processed;
 
 		ARDOUR::DSPLoadCalculator _dsp_calc;