X-Git-Url: https://git.carlh.net/gitweb/?a=blobdiff_plain;f=libs%2Fardour%2Fardour%2Fdsp_load_calculator.h;h=88b327bb300ef8ab85853df680d900aca92248aa;hb=7a524285385d4581ad3f1e085629379e32f82fda;hp=0fed1db7a44b2991a0979346e4cd0c3791d275c3;hpb=1a6c08dcfc07b7254dd2ac4470a363a1a0f94461;p=ardour.git

diff --git a/libs/ardour/ardour/dsp_load_calculator.h b/libs/ardour/ardour/dsp_load_calculator.h
index 0fed1db7a4..88b327bb30 100644
--- a/libs/ardour/ardour/dsp_load_calculator.h
+++ b/libs/ardour/ardour/dsp_load_calculator.h
@@ -19,53 +19,73 @@
 #ifndef ARDOUR_DSP_LOAD_CALCULATOR_H
 #define ARDOUR_DSP_LOAD_CALCULATOR_H
 
+#include <stdlib.h>
 #include <stdint.h>
 #include <cassert>
 #include <algorithm>
 
-#include <pbd/ringbuffer.h>
-
-#include "ardour/libardour_visibility.h"
-
 namespace ARDOUR {
 
-class LIBARDOUR_API DSPLoadCalculator {
+class DSPLoadCalculator {
 public:
 	DSPLoadCalculator()
 	    : m_max_time_us(0)
 	    , m_start_timestamp_us(0)
 	    , m_stop_timestamp_us(0)
 	    , m_dsp_load(0)
-	    , m_value_history (max_value_history())
-	    , m_num_values(0)
 	{
 
 	}
 
+	void set_max_time(double samplerate, uint32_t period_size) {
+		m_max_time_us = period_size * 1e6 / samplerate;
+	}
+
 	void set_max_time_us(uint64_t max_time_us) {
-		assert(m_max_time_us != 0);
+		assert(max_time_us != 0);
 		m_max_time_us = max_time_us;
-
-		// Use average of last 1/4 second of values so responsiveness
-		// remains consistent independent of max time
-		uint32_t max_dsp_samples_per_qtr_second = (250000 / m_max_time_us);
-		m_num_values =
-		    std::min(max_value_history() - 1, max_dsp_samples_per_qtr_second);
-
-		m_value_history.reset();
 	}
 
+	int64_t get_max_time_us() const { return m_max_time_us; }
 
-	uint64_t get_max_time_us() const { return m_max_time_us; }
-
-	void set_start_timestamp_us(uint64_t start_timestamp_us)
+	void set_start_timestamp_us(int64_t start_timestamp_us)
 	{
 		m_start_timestamp_us = start_timestamp_us;
 	}
 
-	void set_stop_timestamp_us(uint64_t stop_timestamp_us);
+	void set_stop_timestamp_us(int64_t stop_timestamp_us)
+	{
+		m_stop_timestamp_us = stop_timestamp_us;
+
+		/* querying the performance counter can fail occasionally (-1).
+		 * Also on some multi-core systems, timers are CPU specific and not
+		 * synchronized. We assume they differ more than a few milliseconds
+		 * (4 * nominal cycle time) and simply ignore cases where the
+		 * execution switches cores.
+		 */
+		if (m_start_timestamp_us < 0 || m_stop_timestamp_us < 0 ||
+		    m_start_timestamp_us > m_stop_timestamp_us ||
+		    elapsed_time_us() > max_timer_error_us()) {
+			return;
+		}
+
+#ifndef NDEBUG
+		const bool calc_avg_load = NULL != getenv("AVGLOAD");
+#else
+		const bool calc_avg_load = false;
+#endif
+
+		const float load = (float) elapsed_time_us() / (float)m_max_time_us;
+		if ((calc_avg_load && load > .95f) || (!calc_avg_load && (load > m_dsp_load || load > 1.f))) {
+			m_dsp_load = load;
+		} else {
+			const float alpha = 0.2f * (m_max_time_us * 1e-6f);
+			m_dsp_load = std::min (1.f, m_dsp_load);
+			m_dsp_load += alpha * (load - m_dsp_load) + 1e-12;
+		}
+	}
 
-	uint64_t elapsed_time_us()
+	int64_t elapsed_time_us()
 	{
 		return m_stop_timestamp_us - m_start_timestamp_us;
 	}
@@ -77,24 +97,32 @@ public:
 	 */
 	float get_dsp_load() const
 	{
-		if (m_dsp_load > m_max_time_us) {
-			return 1.0f;
-		}
-		if (m_dsp_load < 0.0f) {
-			return 0.0f;
-		}
+		assert (m_dsp_load >= 0.f); // since stop > start is assured this cannot happen.
+		return std::min (1.f, m_dsp_load);
+	}
+
+	/**
+	 * @return an unbound value representing the percentage of time spent between
+	 * start and stop in proportion to the max expected time in microseconds(us).
+	 * This is useful for cases to estimate overload (e.g. Dummy backend)
+	 */
+	float get_dsp_load_unbound() const
+	{
+		assert (m_dsp_load >= 0.f);
 		return m_dsp_load;
 	}
-private: // methods
-	static uint32_t max_value_history () { return 16; }
+
+	/**
+	 * The maximum error in timestamp values that will be tolerated before the
+	 * current dsp load sample will be ignored
+	 */
+	int64_t max_timer_error_us() { return 4 * m_max_time_us; }
 
 private: // data
-	uint64_t m_max_time_us;
-	uint64_t m_start_timestamp_us;
-	uint64_t m_stop_timestamp_us;
+	int64_t m_max_time_us;
+	int64_t m_start_timestamp_us;
+	int64_t m_stop_timestamp_us;
 	float m_dsp_load;
-	RingBuffer<float> m_value_history;
-	uint32_t m_num_values;
 };
 
 } // namespace ARDOUR