pa_cpuload.c File Reference

Functions to assist in measuring the CPU utilization of a callback stream. Used to implement the Pa_GetStreamCpuLoad() function. More...

#include "pa_cpuload.h"
#include <assert.h>
#include "pa_util.h"

Macros
#define	LOWPASS_COEFFICIENT_0   (0.9)
#define	LOWPASS_COEFFICIENT_1   (0.99999 - LOWPASS_COEFFICIENT_0)

Functions
void	PaUtil_InitializeCpuLoadMeasurer (PaUtilCpuLoadMeasurer *measurer, double sampleRate)
void	PaUtil_ResetCpuLoadMeasurer (PaUtilCpuLoadMeasurer *measurer)
void	PaUtil_BeginCpuLoadMeasurement (PaUtilCpuLoadMeasurer *measurer)
void	PaUtil_EndCpuLoadMeasurement (PaUtilCpuLoadMeasurer *measurer, unsigned long framesProcessed)
double	PaUtil_GetCpuLoad (PaUtilCpuLoadMeasurer *measurer)

Detailed Description

Functions to assist in measuring the CPU utilization of a callback stream. Used to implement the Pa_GetStreamCpuLoad() function.

Todo:

Dynamically calculate the coefficients used to smooth the CPU Load Measurements over time to provide a uniform characterisation of CPU Load independent of rate at which PaUtil_BeginCpuLoadMeasurement / PaUtil_EndCpuLoadMeasurement are called. see http://www.portaudio.com/trac/ticket/113

Macro Definition Documentation

#define LOWPASS_COEFFICIENT_0   (0.9)

Referenced by PaUtil_EndCpuLoadMeasurement().

#define LOWPASS_COEFFICIENT_1   (0.99999 - LOWPASS_COEFFICIENT_0)

Referenced by PaUtil_EndCpuLoadMeasurement().

Function Documentation

void PaUtil_BeginCpuLoadMeasurement

(

PaUtilCpuLoadMeasurer *

measurer

)

References PaUtilCpuLoadMeasurer::measurementStartTime, and PaUtil_GetTime().

Referenced by PaPulseAudio_WriteStreamBlock(), and ProcessingThreadProc().

void PaUtil_EndCpuLoadMeasurement	(	PaUtilCpuLoadMeasurer *	measurer,
		unsigned long	framesProcessed
	)

FIXME

Todo:

these coefficients shouldn't be hardwired see: http://www.portaudio.com/trac/ticket/113

References PaUtilCpuLoadMeasurer::averageLoad, LOWPASS_COEFFICIENT_0, LOWPASS_COEFFICIENT_1, PaUtilCpuLoadMeasurer::measurementStartTime, PaUtil_GetTime(), and PaUtilCpuLoadMeasurer::samplingPeriod.

Referenced by PaPulseAudio_WriteStreamBlock(), and ProcessingThreadProc().

double PaUtil_GetCpuLoad

(

PaUtilCpuLoadMeasurer *

measurer

)

References PaUtilCpuLoadMeasurer::averageLoad.

Referenced by GetStreamCpuLoad(), and ProcessingThreadProc().

void PaUtil_InitializeCpuLoadMeasurer	(	PaUtilCpuLoadMeasurer *	measurer,
		double	sampleRate
	)

References PaUtilCpuLoadMeasurer::averageLoad, and PaUtilCpuLoadMeasurer::samplingPeriod.

Referenced by OpenStream().

void PaUtil_ResetCpuLoadMeasurer

(

PaUtilCpuLoadMeasurer *

measurer

)

References PaUtilCpuLoadMeasurer::averageLoad.

Referenced by ProcessingThreadProc().