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.

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.

Return

True if the channel is enabled, false if it is disabled.

Parameters

  • channel: A pointer to the channel to check.

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

Get a list of all traceChannels in the session.

Return

A vector of pointers to the traceChannels in the session.

std::string getCurrentTraceFilename(void)

Get the current trace session filename.

Return

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
struct metadata_hash_fn
#include <pvti.hpp>

global metadata hash function for use in the std::unordered_map

Parameters

  • md: The metadata to hash

Public Functions

std::size_t operator()(const Metadata &md) const
class Series

Public Functions

Series(const std::string &name, const Graph &graph, const bool enable = true)
void add(const double value)
void add(const int value)
void enable(void)
void disable(void)
bool check(void) const
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

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

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.

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.

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.

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.

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.

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.