Context is the implicit owner of objects created when it's active and their properties. More...

Data Structures
struct	VPIParallelForConfig
	Stores the ParallelFor configuration. More...

Macros
#define	VPI_INVALID_CONTEXT ((VPIContext)-1)
	Represents a context was destroyed or is invalid for some other reason.

Typedefs
typedef void(*	VPIParallelTask) (int taskId, int threadId, void *vpiData)
	Parallel task function pointer type.

typedef void(*	VPIParallelForCallback) (VPIParallelTask task, int taskCount, void vpiData, void userData)
	Parallel for callback function pointer type. More...

typedef void *	VPINativeThreadHandle
	A handle to OS-specific thread handle.

typedef struct VPIContextImpl *	VPIContext
	A handle to a context.

Functions
VPIStatus	vpiContextCreate (uint32_t flags, VPIContext *ctx)
	Create a context instance. More...

VPIStatus	vpiContextCreateCudaContextWrapper (uint32_t flags, CUcontext cudaCtx, VPIContext *ctx)
	Create a context instance that wraps a CUDA context. More...

void	vpiContextDestroy (VPIContext ctx)
	Destroy a context instance as well as all resources it owns. More...

VPIStatus	vpiContextSetParallelFor (VPIContext ctx, const VPIParallelForConfig *config)
	Controls low-level task parallelism of CPU devices owned by the context. More...

VPIStatus	vpiContextGetParallelFor (VPIContext ctx, VPIParallelForConfig *config)
	Returns parameters set by vpiContextSetParallelFor. More...

VPIStatus	vpiContextGetCurrent (VPIContext *ctx)
	Gets the context for the calling thread. More...

VPIStatus	vpiContextSetCurrent (VPIContext ctx)
	Sets the context for the calling thread. More...

VPIStatus	vpiContextPush (VPIContext ctx)
	Pushes the context to a per-thread context stack and sets this context as the current context for the calling thread. More...

VPIStatus	vpiContextPop (VPIContext *ctx)
	Pops a context from a per-thread context stack and saves it to the ctx variable. More...

VPIStatus	vpiContextGetFlags (VPIContext ctx, uint32_t *flags)
	Get the current context flags. More...

Special contexts
#define	VPI_GLOBAL_CONTEXT ((VPIContext)0x610BA1C1D)
	Global context identifier.

Detailed Description

Context is the implicit owner of objects created when it's active and their properties.

This is a top-level class that manages the lifetime and properties of all other API objects. Specifically, it has the following properties:

Thread-specific - every thread within an application has one current VPIContext instance set. If no instance has been explicitly set for a particular thread, all API calls from this thread will use a process-specific default context instance instead.
Configurable - the user can specify during construction which kinds of backends are enabled for this context. This effectively allows to mask support for a particular hardware. For example, creating a VPIStream instance for a CUDA backend will fail if the current context doesn't have the VPI_BACKEND_CUDA flag set. These flags are also automatically updated to reflect the actual platform support for a particular backend. For example, if the PVA backend is not available, vpiContextGetFlags will return the flag without VPI_BACKEND_PVA set. The CPU backend cannot be masked and is always supported as a fallback implementation though.
Allows for association with a specific CUDA driver API CUcontext instance - this should permit multi-GPU processing.
Sharing buffers between different contexts is not permitted.

Data Structure Documentation

◆ VPIParallelForConfig

struct VPIParallelForConfig

Stores the ParallelFor configuration.

Definition at line 157 of file Types.h.

Collaboration diagram for VPIParallelForConfig:

Data Fields
VPIParallelForCallback	callback	A pointer to the parallel_for implementation. If null is passed, the context will fallback to the default internal parallel_for implementation. parallel_for implementation is required to be thread-safe. Internal API implementation might call this function from different threads at the same time.
int	maxThreads	The maximum number of threads used by the parallel_for implementation code. Has to be larger than 0. Setting the number to N means that the parallel for implementation will call task functors with task id between 0 and N-1. Calling task functors with thread id outside of this range is not legal and will result in undefined behavior.
void *	userData	A user defined opaque pointer passed to callback function unaltered.

Typedef Documentation

◆ VPIParallelForCallback

typedef void(* VPIParallelForCallback) (VPIParallelTask task, int taskCount, void *vpiData, void *userData)

#include <vpi/Types.h>

Parallel for callback function pointer type.

A serial (reference) implementation of this function might looks as follows:

void parallel_for(VPIParallelTask task, int taskCount, void *vpiData, void *userData)
{
   for (int i = 0; i < taskCount; ++i)
   {
     task(i, 0, vpiData); 
   }
}

Parallel implementation should have equivalent behavior; that is, run all tasks between 0 and taskCount-1 and block the calling thread until all tasks have been completed. threadId parameter should be between 0 and maxThreads-1 (

See also: vpiContextSetParallelFor). Implementations that have maxThreads set to zero can pass an arbitrary threadId value to task functions.

Definition at line 150 of file Types.h.

Function Documentation

◆ vpiContextCreate()

VPIStatus vpiContextCreate	(	uint32_t	flags,
		VPIContext *	ctx
	)

#include <vpi/Context.h>

Create a context instance.

Parameters

[in]	flags	Context flags. User can pass a set of VPIBackend flags or-ed together. This will restrict the enabled backends of objects created while this context is active.
[out]	ctx	Pointer to memory that will receive the new context handle.

Returns: an error code on failure else VPI_SUCCESS.

◆ vpiContextCreateCudaContextWrapper()

VPIStatus vpiContextCreateCudaContextWrapper	(	uint32_t	flags,
		CUcontext	cudaCtx,
		VPIContext *	ctx
	)

#include <vpi/Context.h>

Create a context instance that wraps a CUDA context.

CUDA operations will all under the wrapped context whenever the created context is active.

Note: Currently VPI doesn't do anything with the CUDA context, so the call performs exactly like vpiContextCreate().

Parameters

[in]	flags	Context flags. It's assumed that VPI_BACKEND_CUDA is always enabled.
[in]	cudaCtx	CUDA context handle to be wrapped.
[out]	ctx	Pointer to memory that will receive the new context handle.

Returns: an error code on failure else VPI_SUCCESS

◆ vpiContextDestroy()

void vpiContextDestroy ( VPIContext ctx )

#include <vpi/Context.h>

Destroy a context instance as well as all resources it owns.

The context ctx will be destroyed regardless of how many threads it is active in. It is the responsibility of the calling function to ensure that no API call issues using ctx while vpiContextDestroy is executing.

If ctx is current to the calling thread, then ctx will also be popped from the current thread's context stack (as though vpiContextPop was called). If ctx is current to other threads, then ctx will remain current to those threads, and attempting to access ctx from those threads will result in the error VPI_ERROR_INVALID_CONTEXT.

Parameters

[in] ctx Context handle. Passing NULL is accepted. In this case no operation is performed.

◆ vpiContextGetCurrent()

VPIStatus vpiContextGetCurrent ( VPIContext * ctx )

#include <vpi/Context.h>

Gets the context for the calling thread.

If there is no error and current context is NULL, the thread is using the global context.

Parameters

[out] ctx pointer to a context handle

Returns: an error code on failure else VPI_SUCCESS

◆ vpiContextGetFlags()

VPIStatus vpiContextGetFlags	(	VPIContext	ctx,
		uint32_t *	flags
	)

#include <vpi/Context.h>

Get the current context flags.

This function can be used to verify underlying backend support.

Parameters

[in]	ctx	a context handle
[out]	flags	a pointer to a variable which will be set to the current context flags

Returns: an error code on failure else VPI_SUCCESS

◆ vpiContextGetParallelFor()

VPIStatus vpiContextGetParallelFor	(	VPIContext	ctx,
		VPIParallelForConfig *	config
	)

#include <vpi/Context.h>

Returns parameters set by vpiContextSetParallelFor.

Parameters

[in]	ctx	Context handle
[out]	config	A pointer to parallel_for configuration.

Returns: an error code on failure else VPI_SUCCESS

◆ vpiContextPop()

VPIStatus vpiContextPop ( VPIContext * ctx )

#include <vpi/Context.h>

Pops a context from a per-thread context stack and saves it to the ctx variable.

The top of the context stack is set as the current context for the calling thread.

Parameters

[out] ctx pointer to a context handle

Returns: an error code on failure else VPI_SUCCESS

◆ vpiContextPush()

VPIStatus vpiContextPush ( VPIContext ctx )

#include <vpi/Context.h>

Pushes the context to a per-thread context stack and sets this context as the current context for the calling thread.

Parameters

[in] ctx Context handle

Returns: an error code on failure else VPI_SUCCESS

◆ vpiContextSetCurrent()

VPIStatus vpiContextSetCurrent ( VPIContext ctx )

#include <vpi/Context.h>

Sets the context for the calling thread.

If there are items on the context stack this will replace the top of the stack. If ctx is NULL this will clear the context stack and make the thread use the global context.

Parameters

[in] ctx a context handle

Returns: an error code on failure else VPI_SUCCESS

◆ vpiContextSetParallelFor()

VPIStatus vpiContextSetParallelFor	(	VPIContext	ctx,
		const VPIParallelForConfig *	config
	)

#include <vpi/Context.h>

Controls low-level task parallelism of CPU devices owned by the context.

This function allows the user to overload the parallel_for implementation used by CPU devices. Changing this parallel_for implementation on a context that is performing CPU processing is undefined and might lead to application crashes.

Parameters

[in]	ctx	Context handle.
[in]	config	A pointer to parallel_for configuration. Passing NULL will make the context to fallback to its default internal implementation.

Returns: an error code on failure else VPI_SUCCESS

VPI - Vision Programming Interface

1.2 Release

Data Structures

Macros

Typedefs

Functions

Special contexts

Detailed Description

Data Structure Documentation

◆ VPIParallelForConfig

Typedef Documentation

◆ VPIParallelForCallback

Function Documentation

◆ vpiContextCreate()

◆ vpiContextCreateCudaContextWrapper()

◆ vpiContextDestroy()

◆ vpiContextGetCurrent()

◆ vpiContextGetFlags()

◆ vpiContextGetParallelFor()

◆ vpiContextPop()

◆ vpiContextPush()

◆ vpiContextSetCurrent()

◆ vpiContextSetParallelFor()