2. PopVision trace instrumentation library C++ API

namespace pvti

TraceChannels

PVTI library predefined trace categories.

These predefined channels can be enabled or disabled at runtime. Tracepoints can be created using these channels, or custom channels can be added.

TraceChannel traceDrivers

TraceChannel tracePoplar

Typedefs

typedef struct pvti::TraceChannel TraceChannel

PVTI trace categories type definition.

Use for defining custom channels.

typedef struct pvti::ThreadName ThreadName

Functions

void enableTraceChannel(TraceChannel *channel)

Enable tracing channel for the session.

PVTI_OPTIONS environment variable must be set, and trace enabled. See “Configuring trace options” for more information.

Parameters: channel – A pointer to the channel to be enabled.

void disableTraceChannel(TraceChannel *channel)

Disable tracing channel for the session.

Parameters: channel – A pointer to the channel to be disabled.

bool checkTraceChannel(TraceChannel *channel)

Check if tracing channel is enabled.

Parameters: channel – A pointer to the channel to check.
Returns: True if the channel is enabled, false if it is disabled.

std::vector<TraceChannel*> listTraceChannel(void)

Get a list of all traceChannels in the session.

Returns: A vector of pointers to the traceChannels in the session.

std::string getCurrentTraceFilename(void)

Get the current trace session filename.

Returns: The current trace session filename.

void closeTrace()

Close the current trace session.

No Tracepoint events should be invoked following this function call.

Metadata createJsonMetadata(const std::string &json)

Helper function to create a metadata object from a json string.

Parameters: json – A json string

class Client

#include <pvti.hpp>

PVTI Client class should be added to any singleton which contains PVTI clients like Tracepoint, Graph and Series.

This is to ensure that PVTI Session singleton is created early on and it does not go out of scope before any of its clients.

Public Functions

Client()

class Graph

Public Functions

Graph(const std::string &name, const std::string &unit = "", const bool enable = true)

pvti::Series addSeries(const std::string &name, const bool enable = true)

void enable(void)

void disable(void)

bool check(void) const

int32_t getId(void) const

std::string getName(void) const

class Metadata

#include <pvti.hpp>

Base class for creating metadata.

It allows attaching extra information to Trace events. The class is not intended to be subclassed but instead created directly, maybe with the use of helper functions like createJsonMetadata

Public Functions

Metadata(const std::string &type)

Metadata constructor.

Parameters: type – Type information which describes the format of the data parameter (for example, “json”). The type must be recognised by the System Analyser in order for data to be displayed correctly.

Metadata(const Metadata&) = default: Default copy constructor.

Metadata(Metadata&&) = default: Default move constrcutor.

Metadata &operator=(const Metadata&) = default: Default assignment operator.

bool operator==(const Metadata &other) const: Equality operator operator== is required to compare keys in case of a hash collision.

void writeU8(uint8_t value): Write methods to put data in to the meta data buffer.

void writeU16(uint16_t value)

void writeU32(uint32_t value)

void writeBuffer(const uint8_t *const value, unsigned len)

std::size_t hash() const noexcept: Metadata hash method Calculate the hash for this meta data.

Public Members

std::vector<uint8_t> data

std::string type

class Series

Public Functions

Series(const std::string &name, const Graph &graph, const bool enable = true)

void add(const double value)

inline void add(const int value)

void enable(void)

void disable(void)

bool check(void) const

struct ThreadName

Public Functions

ThreadName(const char *tname)

Construct a ThreadName object for calling thread, and add it to the current session.

Parameters: tname – thread name to be set

struct TraceChannel

#include <pvti.hpp>

PVTI trace categories type definition.

Use for defining custom channels.

Public Functions

TraceChannel(const char *name, bool enabled = true)

Construct a TraceChannel object, and add it to the current session.

Parameters

name – The channel name.
enabled – Set this to true to enable the channel when it is declared. enableTraceChannel() and disableTraceChannel() can be used to enable or disable channels at runtime.

Public Members

const char *name

bool enabled

class Tracepoint

#include <pvti.hpp>

Class for managing tracing of events.

Public Functions

Tracepoint(TraceChannel *traceChannel, const std::string traceLabel, const Metadata *metadata = nullptr)

Profile a function or a scope by creating a named stack object of Tracepoint type.

Parameters

traceChannel – The channel to create the tracepoint for
traceLabel – A unique user-friendly string for this scope’s trace.
metadata – A metadata object associated with the event.

Tracepoint(TraceChannel *traceChannel, const char *traceLabel, const int32_t traceLabelLen = -1, const Metadata *metadata = nullptr)

Profile a function or a scope by creating a named stack object of Tracepoint type.

Parameters

traceChannel – The channel to create the tracepoint for.
traceLabel – A unique user-friendly string for this scope’s trace.
traceLabelLen – The number of characters to use from the traceLabel (-1 indicates all).
metadata – A metadata object associated with the event.

~Tracepoint(): Invoked on Tracepoint function exit.

Tracepoint(const Tracepoint&) = delete

Tracepoint &operator=(const Tracepoint&) = delete

Public Static Functions

static void begin(TraceChannel *traceChannel, const std::string traceLabel, const Metadata *metadata = nullptr)

Start profiling a region using this function.

Should be complemented with an end() to profile between the two.

Parameters

traceChannel – The channel to create tracepoints for.
traceLabel – A unique user-friendly string for this region’s trace.
metadata – A metadata object associated with the event.

static void begin(TraceChannel *traceChannel, const char *traceLabel, const int32_t traceLabelLen = -1, const Metadata *metadata = nullptr)

Start profiling a region using this function.

Should be complemented with with an end() to profile between the two.

Parameters

traceChannel – The channel to create tracepoints for.
traceLabel – A unique user-friendly string for this region’s trace.
traceLabelLen – The number of characters to use from the traceLabel (-1 indicates all).
metadata – A metadata object associated with the event.

static void end(TraceChannel *traceChannel, const std::string traceLabel, const Metadata *metadata = nullptr)

End profiling a region using this function.

Should be the complement to a begin() to profile between the two.

Parameters

traceChannel – The channel to create tracepoints for.
traceLabel – A unique user-friendly string for this region’s trace.
metadata – A metadata object associated with the event.

static void end(TraceChannel *traceChannel, const char *traceLabel, const int32_t traceLabelLen = -1, const Metadata *metadata = nullptr)

End profiling a region using this function.

Should be the complement to a begin() to profile between the two.

Parameters

traceChannel – The channel to create tracepoints for.
traceLabel – A unique user-friendly string for this region’s trace.
traceLabelLen – The number of characters to use from the traceLabel (-1 indicates all).
metadata – A metadata object associated with the event.

static void event(TraceChannel *traceChannel, const std::string traceLabel, const Metadata *metadata = nullptr)

Mark an occurrence to be instrumented.

Can be used to compute duration between two events of the same or different type.

Parameters

traceChannel – The channel to create tracepoints for.
traceLabel – A unique user-friendly string for this event.
metadata – A metadata object associated with the event.

static void event(TraceChannel *traceChannel, const char *traceLabel, const int32_t len = -1, const Metadata *metadata = nullptr)

Mark an occurrence to be instrumented.

Can be used to compute duration between two events of same or different type.

Parameters

traceChannel – The channel to create tracepoints for.
traceLabel – A unique user-friendly string for this event.
traceLabelLen – The number of characters to use from the traceLabel (-1 indicates all).
metadata – A metadata object associated with the event.