Jetson Inference: Multithreading - Jetson Inference

| | Jetson Inference

DNN Vision Library |

Multithreading Utilities Library (jetson-utils)

Mutex, events, threads, and process objects based on pthreads. More...

Classes

Typedefs

| | typedef void *(* | ThreadEntryFunction) (void *user_param) | | | Function pointer typedef representing a thread's main entry point. More...
| | |

Detailed Description

Mutex, events, threads, and process objects based on pthreads.

Class Documentation

◆Event

| class Event |

Event object for signalling other threads.

Public Member Functions

Protected Attributes

Constructor & Destructor Documentation

◆Event()

| inline |

Event constructor.

By default, it will automatically be reset when it's raised.

Parameters

| auto_reset | Once this event has been raised, should it automatically be reset? |

◆~Event()

| Event::~Event | ( | | ) | |

| inline |

Destructor.

Member Function Documentation

◆GetID()

| pthread_cond_t* Event::GetID | ( | | ) | |

| inline |

Get the Event object.

◆Query()

| bool Event::Query | ( | | ) | |

| inline |

Query the status of this event.

ReturnsTrue if the event is raised, false if not.

◆Reset()

| void Event::Reset | ( | | ) | |

| inline |

Reset the event status to un-raised.

◆Wait() [1/3]

| bool Event::Wait | ( | | ) | |

| inline |

Wait until this event is raised.

It is likely this will block this thread (and will never timeout).

See alsoWake

◆Wait() [2/3]

| inline |

Wait for a specified amount of time until this event is raised or timeout occurs.

See alsoWake

◆Wait() [3/3]

| inline |

Wait for a specified number of milliseconds until this event is raised or timeout occurs.

See alsoWake

◆WaitNs()

| inline |

Wait for a specified number of nanoseconds until this event is raised or timeout occurs.

See alsoWake

◆WaitUs()

| inline |

Wait for a specified number of microseconds until this event is raised or timeout occurs.

See alsoWake

◆Wake()

| void Event::Wake | ( | | ) | |

| inline |

Raise the event.

Any threads waiting on this event will be woken up.

Member Data Documentation

◆mAutoReset

| bool Event::mAutoReset |

| protected |

◆mID

| pthread_cond_t Event::mID |

| protected |

◆mQuery

| bool Event::mQuery |

| protected |

◆mQueryMutex

| Mutex Event::mQueryMutex |

| protected |

◆Mutex

| class Mutex |

A lightweight mutual exclusion lock.

It is very fast to check if the mutex is available, lock it, and release it. However, if the mutex is unavailable when you attempt to lock it, execution of the thread will stop until it becomes available.

Public Member Functions

Protected Attributes

| | pthread_mutex_t | mID | | |

Constructor & Destructor Documentation

◆Mutex()

| Mutex::Mutex | ( | | ) | |

| inline |

Constructor.

◆~Mutex()

| Mutex::~Mutex | ( | | ) | |

| inline |

Destructor.

Member Function Documentation

◆AttemptLock()

| bool Mutex::AttemptLock | ( | | ) | |

| inline |

If the lock is free, aquire it.

Otherwise, return without waiting for it to become available.

ReturnsTrue if the lock was aquired, false if not.

◆GetID()

| pthread_mutex_t* Mutex::GetID | ( | | ) | |

| inline |

Get the mutex object.

◆Lock()

| void Mutex::Lock | ( | | ) | |

| inline |

Aquire the lock, whenever it becomes available.

This could mean just a few instructions if the lock is already free, or to block the thread if it isn't.

◆Sync()

| void Mutex::Sync | ( | | ) | |

| inline |

Wait for the lock, then release it immediately.

Use this in situations where you are waiting for an event to occur.

◆Unlock()

| void Mutex::Unlock | ( | | ) | |

| inline |

Release the lock.

Member Data Documentation

◆mID

| pthread_mutex_t Mutex::mID |

| protected |

◆Process

| class Process |

Static functions for retrieving information about the running process.

Static Public Member Functions

Member Function Documentation

◆Fork()

| static void Process::Fork | ( | | ) | |

| static |

Duplicate the calling process.

◆GetCommandLine()

| static std::string Process::GetCommandLine | ( | pid_t | pid = -1 | ) | |

| static |

Retrieve the command line of the process with the specified PID, or of this calling process if PID is -1 (which is the default).

◆GetExecutableDir()

| static std::string Process::GetExecutableDir | ( | pid_t | pid = -1 | ) | |

| static |

Retrieve the directory that the process executable resides in.

For example, if the process executable is located at /usr/bin/exe, then GetExecutableDir() would return the path /usr/bin. If the specified PID is -1, then the calling process will be used.

◆GetExecutablePath()

| static std::string Process::GetExecutablePath | ( | pid_t | pid = -1 | ) | |

| static |

Retrieve the absolute path of the process with the specified PID, or of this calling process if PID is -1 (which is the default).

This path will include the process' filename.

◆GetID()

| static pid_t Process::GetID | ( | | ) | |

| static |

Get this process ID (PID)

◆GetParentID()

| static pid_t Process::GetParentID | ( | | ) | |

| static |

Get the parent's process ID.

◆GetWorkingDir()

| static std::string Process::GetWorkingDir | ( | pid_t | pid = -1 | ) | |

| static |

Retrieve the current working directory of the process.

If the specified PID is -1, then the calling process will be used.

◆RingBuffer

| class RingBuffer |

Thread-safe circular ring buffer queue.

Public Types

| | enum | Flags {
Read = (1 << 0), ReadOnce = (1 << 1) | Read, ReadLatest = (1 << 2) | Read, ReadLatestOnce = (1 << 3) | ReadLatest,
Write = (1 << 4), Threaded = (1 << 5), ZeroCopy = (1 << 6)
} | | | Ring buffer flags. More...
| | | |

Public Member Functions

Protected Attributes

Member Enumeration Documentation

◆Flags

| enum RingBuffer::Flags |

Ring buffer flags.

Enumerator
Read

Read the next buffer.

| | ReadOnce |

Read the next buffer, but only if it hasn't been read before.

| | ReadLatest |

Read the latest buffer in the queue, skipping other buffers that may not have been read.

| | ReadLatestOnce |

Combination of ReadOnce and ReadLatest flags.

| | Write |

Write the next buffer.

| | Threaded |

Buffers should be thread-safe (enabled by default).

| | ZeroCopy |

Buffers should be allocated in mapped CPU/GPU zeroCopy memory (otherwise GPU only)

Constructor & Destructor Documentation

◆RingBuffer()

| inline |

Construct a new ring buffer.

◆~RingBuffer()

| RingBuffer::~RingBuffer | ( | | ) | |

| inline |

Destructor.

Member Function Documentation

◆Alloc()

| inline |

Allocate memory for a set of buffers, where each buffer has the specified size.

If the requested allocation is compatible with what was already allocated, this will return true without performing additional allocations. Otherwise, the previous buffers are released and new ones are allocated.

Returnstrue if the allocations succeeded or was previously done. false if a memory allocation error occurred.

◆Free()

| void RingBuffer::Free | ( | | ) | |

| inline |

Free the buffer allocations.

◆GetFlags()

| uint32_t RingBuffer::GetFlags | ( | | ) | const |

| inline |

Get the flags of the ring buffer.

◆Next()

| inline |

Get the next read/write buffer and advance the position in the queue.

◆Peek()

| inline |

Get the next read/write buffer without advancing the position in the queue.

◆SetFlags()

| inline |

Set the ring buffer's flags.

◆SetThreaded()

| inline |

Enable or disable multi-threading.

Member Data Documentation

◆mBuffers

| void** RingBuffer::mBuffers |

| protected |

◆mBufferSize

| size_t RingBuffer::mBufferSize |

| protected |

◆mFlags

| uint32_t RingBuffer::mFlags |

| protected |

◆mLatestRead

| uint32_t RingBuffer::mLatestRead |

| protected |

◆mLatestWrite

| uint32_t RingBuffer::mLatestWrite |

| protected |

◆mMutex

| Mutex RingBuffer::mMutex |

| protected |

◆mNumBuffers

| uint32_t RingBuffer::mNumBuffers |

| protected |

◆mReadOnce

| bool RingBuffer::mReadOnce |

| protected |

◆Thread

| class Thread |

Thread class for launching an asynchronous operating-system dependent thread.

To make your own thread, provide a function pointer of the thread's entry point, or inherit from this class and implement your own Run() function.

Public Member Functions

Static Public Member Functions

Static Protected Member Functions

Protected Attributes

Constructor & Destructor Documentation

◆Thread()

| Thread::Thread | ( | | ) | |

Default constructor.

◆~Thread()

| virtual Thread::~Thread | ( | | ) | |

| virtual |

Destructor.

Automatically stops the thread.

Member Function Documentation

◆DefaultEntry()

| staticprotected |

◆GetCPU()

| static int Thread::GetCPU | ( | | ) | |

| static |

Look up which CPU core the thread is running on.

◆GetMaxPriority()

| static int Thread::GetMaxPriority | ( | | ) | |

| static |

Get the maximum priority level available.

◆GetMinPriority()

| static int Thread::GetMinPriority | ( | | ) | |

| static |

Get the minimum priority level avaiable.

◆GetPriority()

| static |

Get the priority level of the thread.

Parameters

| thread | The thread, or if NULL, the currently running thread. |

◆GetPriorityLevel()

| int Thread::GetPriorityLevel | ( | | ) | |

Get this thread's priority level.

◆GetThreadID()

| pthread_t* Thread::GetThreadID | ( | | ) | |

| inline |

Get thread identififer.

◆InitRealtime()

| static void Thread::InitRealtime | ( | | ) | |

| static |

Prime the system for realtime use.

Mostly this is locking a large group of pages into memory.

◆LockAffinity()

| bool Thread::LockAffinity | ( | unsigned int | cpu | ) | |

Lock this thread to a CPU core.

◆Run()

| virtual void Thread::Run | ( | | ) | |

| virtual |

User-implemented thread main() function.

◆SetAffinity()

| static bool Thread::SetAffinity | ( | unsigned int | cpu, | | | | pthread_t * | thread = NULL | | | ) | | |

| static |

Lock the specified thread's affinity to a CPU core.

Parameters

◆SetPriority()

| static int Thread::SetPriority | ( | int | priority, | | | | pthread_t * | thread = NULL | | | ) | | |

| static |

Set the priority level of the thread.

Parameters

| thread | The thread, or if NULL, the currently running thread. |

◆SetPriorityLevel()

| bool Thread::SetPriorityLevel | ( | int | priority | ) | |

Set this thread's priority level.

◆Start() [1/2]

| bool Thread::Start | ( | | ) | |

Start the thread.

This will asynchronously call the Run() function.

ReturnsFalse if an error occurred and the thread could not be started.

◆Start() [2/2]

Start the thread, utilizing an entry function pointer provided by the user.

ReturnsFalse if an error occurred and the thread could not be started.

◆Stop()

Signal for the thread to stop running.

If wait is true, Stop() will block until the thread has exited.

◆Yield()

| static void Thread::Yield | ( | unsigned int | ms | ) | |

| static |

Whatever thread you are calling from, yield the processor for the specified number of milliseconds.

Accuracy may vary wildly the lower you go, and depending on the platform.

Member Data Documentation

◆mThreadID

| pthread_t Thread::mThreadID |

| protected |

◆mThreadStarted

| bool Thread::mThreadStarted |

| protected |

Typedef Documentation

◆ThreadEntryFunction

| typedef void*(* ThreadEntryFunction) (void *user_param) |

Function pointer typedef representing a thread's main entry point.

A user-defined parameter is passed through such that the user can pass data or other value to their thread so that it can self-identify.

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