Changeset - r23060:230e0b87f745
[Not reviewed]
master
0 2 0
Niels Martin Hansen - 6 years ago 2018-10-27 16:04:40
nielsm@indvikleren.dk
Doc: More notes for developers adding new PerformanceElements
2 files changed with 82 insertions and 9 deletions:
0 comments (0 inline, 0 general)
src/framerate_gui.cpp
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@@ -22,11 +22,14 @@
 
#include "widgets/framerate_widget.h"
 

	
 

	
 
/**
 
 * Private declarations for performance measurement implementation
 
 */
 
namespace {
 

	
 
	/** Number of data points to keep in buffer for each performance measurement */
 
	const int NUM_FRAMERATE_POINTS = 512;
 
	/** Units a second is divided into in performance measurements */
 
	/** %Units a second is divided into in performance measurements */
 
	const TimingMeasurement TIMESTAMP_PRECISION = 1000000;
 

	
 
	struct PerformanceData {
 
@@ -51,8 +54,15 @@ namespace {
 
		/** Start time for current accumulation cycle */
 
		TimingMeasurement acc_timestamp;
 

	
 
		/**
 
		 * Initialize a data element with an expected collection rate
 
		 * @param expected_rate
 
		 * Expected number of cycles per second of the performance element. Use 1 if unknown or not relevant.
 
		 * The rate is used for highlighting slow-running elements in the GUI.
 
		 */
 
		explicit PerformanceData(double expected_rate) : expected_rate(expected_rate), next_index(0), prev_index(0), num_valid(0) { }
 

	
 
		/** Collect a complete measurement, given start and ending times for a processing block */
 
		void Add(TimingMeasurement start_time, TimingMeasurement end_time)
 
		{
 
			this->durations[this->next_index] = end_time - start_time;
 
@@ -63,6 +73,7 @@ namespace {
 
			this->num_valid = min(NUM_FRAMERATE_POINTS, this->num_valid + 1);
 
		}
 

	
 
		/** Begin an accumulation of multiple measurements into a single value, from a given start time */
 
		void BeginAccumulate(TimingMeasurement start_time)
 
		{
 
			this->timestamps[this->next_index] = this->acc_timestamp;
 
@@ -76,11 +87,13 @@ namespace {
 
			this->acc_timestamp = start_time;
 
		}
 

	
 
		/** Accumulate a period onto the current measurement */
 
		void AddAccumulate(TimingMeasurement duration)
 
		{
 
			this->acc_duration += duration;
 
		}
 

	
 
		/** Indicate a pause/expected discontinuity in processing the element */
 
		void AddPause(TimingMeasurement start_time)
 
		{
 
			if (this->durations[this->prev_index] != INVALID_DURATION) {
 
@@ -125,11 +138,11 @@ namespace {
 
			int last_point = this->next_index - this->num_valid;
 
			if (last_point < 0) last_point += NUM_FRAMERATE_POINTS;
 

	
 
			/** Number of data points collected */
 
			/* Number of data points collected */
 
			int count = 0;
 
			/** Time of previous data point */
 
			/* Time of previous data point */
 
			TimingMeasurement last = this->timestamps[point];
 
			/** Total duration covered by collected points */
 
			/* Total duration covered by collected points */
 
			TimingMeasurement total = 0;
 

	
 
			while (point != last_point) {
 
@@ -149,9 +162,14 @@ namespace {
 
		}
 
	};
 

	
 
	/** Game loop rate, cycles per second */
 
	/** %Game loop rate, cycles per second */
 
	static const double GL_RATE = 1000.0 / MILLISECONDS_PER_TICK;
 

	
 
	/**
 
	 * Storage for all performance element measurements.
 
	 * Elements are initialized with the expected rate in recorded values per second.
 
	 * @hideinitializer
 
	 */
 
	PerformanceData _pf_data[PFE_MAX] = {
 
		PerformanceData(GL_RATE),               // PFE_GAMELOOP
 
		PerformanceData(1),                     // PFE_ACC_GL_ECONOMY
 
@@ -182,7 +200,10 @@ static TimingMeasurement GetPerformanceT
 
}
 

	
 

	
 
/** Begin a cycle of a measured element. */
 
/**
 
 * Begin a cycle of a measured element.
 
 * @param elem The element to be measured
 
 */
 
PerformanceMeasurer::PerformanceMeasurer(PerformanceElement elem)
 
{
 
	assert(elem < PFE_MAX);
 
@@ -203,14 +224,20 @@ void PerformanceMeasurer::SetExpectedRat
 
	_pf_data[this->elem].expected_rate = rate;
 
}
 

	
 
/** Indicate that a cycle of "pause" where no processing occurs. */
 
/**
 
 * Indicate that a cycle of "pause" where no processing occurs.
 
 * @param elem The element not currently being processed
 
 */
 
void PerformanceMeasurer::Paused(PerformanceElement elem)
 
{
 
	_pf_data[elem].AddPause(GetPerformanceTimer());
 
}
 

	
 

	
 
/** Begin measuring one block of the accumulating value. */
 
/**
 
 * Begin measuring one block of the accumulating value.
 
 * @param elem The element to be measured
 
 */
 
PerformanceAccumulator::PerformanceAccumulator(PerformanceElement elem)
 
{
 
	assert(elem < PFE_MAX);
 
@@ -225,7 +252,11 @@ PerformanceAccumulator::~PerformanceAccu
 
	_pf_data[this->elem].AddAccumulate(GetPerformanceTimer() - this->start_time);
 
}
 

	
 
/** Store the previous accumulator value and reset for a new cycle of accumulating measurements. */
 
/**
 
 * Store the previous accumulator value and reset for a new cycle of accumulating measurements.
 
 * @note This function must be called once per frame, otherwise measurements are not collected.
 
 * @param elem The element to begin a new measurement cycle of
 
 */
 
void PerformanceAccumulator::Reset(PerformanceElement elem)
 
{
 
	_pf_data[elem].BeginAccumulate(GetPerformanceTimer());
 
@@ -235,6 +266,7 @@ void PerformanceAccumulator::Reset(Perfo
 
void ShowFrametimeGraphWindow(PerformanceElement elem);
 

	
 

	
 
/** @hideinitializer */
 
static const NWidgetPart _framerate_window_widgets[] = {
 
	NWidget(NWID_HORIZONTAL),
 
		NWidget(WWT_CLOSEBOX, COLOUR_GREY),
 
@@ -478,6 +510,7 @@ static WindowDesc _framerate_display_des
 
);
 

	
 

	
 
/** @hideinitializer */
 
static const NWidgetPart _frametime_graph_window_widgets[] = {
 
	NWidget(NWID_HORIZONTAL),
 
		NWidget(WWT_CLOSEBOX, COLOUR_GREY),
 
@@ -758,17 +791,20 @@ static WindowDesc _frametime_graph_windo
 

	
 

	
 

	
 
/** Open the general framerate window */
 
void ShowFramerateWindow()
 
{
 
	AllocateWindowDescFront<FramerateWindow>(&_framerate_display_desc, 0);
 
}
 

	
 
/** Open a graph window for a performance element */
 
void ShowFrametimeGraphWindow(PerformanceElement elem)
 
{
 
	if (elem < PFE_FIRST || elem >= PFE_MAX) return; // maybe warn?
 
	AllocateWindowDescFront<FrametimeGraphWindow>(&_frametime_graph_window_desc, elem, true);
 
}
 

	
 
/** Print performance statistics to game console */
 
void ConPrintFramerate()
 
{
 
	const int count1 = NUM_FRAMERATE_POINTS / 8;
src/framerate_type.h
Show inline comments
 
@@ -9,6 +9,28 @@
 

	
 
/** @file framerate_type.h
 
 * Types for recording game performance data.
 
 *
 
 * @par Adding new measurements
 
 * Adding a new measurement requires multiple steps, which are outlined here.
 
 * The first thing to do is add a new member of the #PerformanceElement enum.
 
 * It must be added before \c PFE_MAX and should be added in a logical place.
 
 * For example, an element of the game loop would be added next to the other game loop elements, and a rendering element next to the other rendering elements.
 
 *
 
 * @par
 
 * Second is adding a member to the \link anonymous_namespace{framerate_gui.cpp}::_pf_data _pf_data \endlink array, in the same position as the new #PerformanceElement member.
 
 *
 
 * @par
 
 * Third is adding strings for the new element. There is an array in #ConPrintFramerate with strings used for the console command.
 
 * Additionally, there are two sets of strings in \c english.txt for two GUI uses, also in the #PerformanceElement order.
 
 * Search for \c STR_FRAMERATE_GAMELOOP and \c STR_FRAMETIME_CAPTION_GAMELOOP in \c english.txt to find those.
 
 *
 
 * @par
 
 * Last is actually adding the measurements. There are two ways to measure, either one-shot (a single function/block handling all processing),
 
 * or as an accumulated element (multiple functions/blocks that need to be summed across each frame/tick).
 
 * Use either the PerformanceMeasurer or the PerformanceAccumulator class respectively for the two cases.
 
 * Either class is used by instantiating an object of it at the beginning of the block to be measured, so it auto-destructs at the end of the block.
 
 * For PerformanceAccumulator, make sure to also call PerformanceAccumulator::Reset once at the beginning of a new frame. Usually the StateGameLoop function is appropriate for this.
 
 *
 
 * @see framerate_gui.cpp for implementation
 
 */
 

	
 
@@ -18,6 +40,12 @@
 
#include "stdafx.h"
 
#include "core/enum_type.hpp"
 

	
 
/**
 
 * Elements of game performance that can be measured.
 
 *
 
 * @note When adding new elements here, make sure to also update all other locations depending on the length and order of this enum.
 
 * See <em>Adding new measurements</em> above.
 
 */
 
enum PerformanceElement {
 
	PFE_FIRST = 0,
 
	PFE_GAMELOOP = 0,  ///< Speed of gameloop processing.
 
@@ -36,12 +64,15 @@ enum PerformanceElement {
 
};
 
DECLARE_POSTFIX_INCREMENT(PerformanceElement)
 

	
 
/** Type used to hold a performance timing measurement */
 
typedef uint64 TimingMeasurement;
 

	
 
/**
 
 * RAII class for measuring simple elements of performance.
 
 * Construct an object with the appropriate element parameter when processing begins,
 
 * time is automatically taken when the object goes out of scope again.
 
 *
 
 * Call Paused at the start of a frame if the processing of this element is paused.
 
 */
 
class PerformanceMeasurer {
 
	PerformanceElement elem;
 
@@ -57,6 +88,12 @@ public:
 
 * RAII class for measuring multi-step elements of performance.
 
 * At the beginning of a frame, call Reset on the element, then construct an object in the scope where
 
 * each processing cycle happens. The measurements are summed between resets.
 
 *
 
 * Usually StateGameLoop is an appropriate function to place Reset calls in, but for elements with
 
 * more isolated scopes it can also be appropriate to Reset somewhere else.
 
 * An example is the CallVehicleTicks function where all the vehicle type elements are reset.
 
 *
 
 * The PerformanceMeasurer::Paused function can also be used with elements otherwise measured with this class.
 
 */
 
class PerformanceAccumulator {
 
	PerformanceElement elem;
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