c_backend_api.h File Reference

TVM runtime backend API. More...

#include <tvm/runtime/base.h>

Include dependency graph for c_backend_api.h:

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Classes
struct	TVMParallelGroupEnv
	Environment for TVM parallel task. More...

Typedefs
typedef int(*	FTVMParallelLambda) (int task_id, TVMParallelGroupEnv *penv, void *cdata)
	The callback function to execute a parallel lambda.

Functions
TVM_RUNTIME_DLL int	TVMBackendSetDevice (int device_type, int device_index)
	Select the runtime device for the calling host thread.
TVM_RUNTIME_DLL int	TVMBackendGetDeviceIndex (int device_type, int *out_device_index)
	Query the selected runtime device index on the calling host thread.
TVM_RUNTIME_DLL void *	TVMBackendAllocWorkspace (int device_type, int device_id, uint64_t nbytes, int dtype_code_hint, int dtype_bits_hint)
	Backend function to allocate temporal workspace.
TVM_RUNTIME_DLL int	TVMBackendFreeWorkspace (int device_type, int device_id, void *ptr)
	Backend function to free temporal workspace.
TVM_RUNTIME_DLL int	TVMBackendParallelLaunch (FTVMParallelLambda flambda, void *cdata, int num_task)
	Backend function for running parallel jobs.
TVM_RUNTIME_DLL int	TVMBackendParallelBarrier (int task_id, TVMParallelGroupEnv *penv)
	BSP barrrier between parallel threads.

Detailed Description

TVM runtime backend API.

The functions defined in this header are intended to be used by compiled tvm operators, usually user do not need to use these function directly.

Typedef Documentation

FTVMParallelLambda

typedef int(* FTVMParallelLambda) (int task_id, TVMParallelGroupEnv *penv, void *cdata)

The callback function to execute a parallel lambda.

Parameters

task_id	the task id of the function.
penv	The parallel environment backs the execution.
cdata	The supporting closure data.

Function Documentation

TVMBackendAllocWorkspace()

TVM_RUNTIME_DLL void * TVMBackendAllocWorkspace	(	int	device_type,
		int	device_id,
		uint64_t	nbytes,
		int	dtype_code_hint,
		int	dtype_bits_hint
	)

Backend function to allocate temporal workspace.

Note

The result allocated space is ensured to be aligned to kTempAllocaAlignment.

Parameters

nbytes	The size of the space requested.
device_type	The device type which the space will be allocated.
device_id	The device id which the space will be allocated.
dtype_code_hint	The type code of the array elements. Only used in certain backends such as OpenGL.
dtype_bits_hint	The type bits of the array elements. Only used in certain backends such as OpenGL.

Returns

nullptr when error is thrown, a valid ptr if success

TVMBackendFreeWorkspace()

TVM_RUNTIME_DLL int TVMBackendFreeWorkspace	(	int	device_type,
		int	device_id,
		void *	ptr
	)

Backend function to free temporal workspace.

Parameters

ptr	The result allocated space pointer.
device_type	The device type which the space will be allocated.
device_id	The device id which the space will be allocated.

Returns

0 when no error is thrown, -1 when failure happens

See also

TVMBackendAllocWorkspace

TVMBackendGetDeviceIndex()

TVM_RUNTIME_DLL int TVMBackendGetDeviceIndex	(	int	device_type,
		int *	out_device_index
	)

Query the selected runtime device index on the calling host thread.

Dispatches to DeviceAPI::GetDeviceIndex without changing device selection. Getter support is optional and independent of setter support: the default implementation reports NotImplementedError, including for backends without device-selection state. RPC devices are not supported.

Parameters

device_type	Local DLPack device type, not an RPC session-encoded type.
out_device_index	Non-null pointer receiving the runtime device index (DLDevice::device_id), not a device type or target configuration index. Written only on success; its previous value is unchanged on failure.

Returns

0 on success, -1 on invalid arguments, unavailable backend, unsupported query, or backend failure. Failure records the raised TVM FFI error on the calling thread; no C++ exception crosses this C entry point.

TVMBackendParallelBarrier()

TVM_RUNTIME_DLL int TVMBackendParallelBarrier	(	int	task_id,
		TVMParallelGroupEnv *	penv
	)

BSP barrrier between parallel threads.

Parameters

task_id	the task id of the function.
penv	The parallel environment backs the execution.

Returns

0 when no error is thrown, -1 when failure happens

TVMBackendParallelLaunch()

TVM_RUNTIME_DLL int TVMBackendParallelLaunch	(	FTVMParallelLambda	flambda,
		void *	cdata,
		int	num_task
	)

Backend function for running parallel jobs.

Parameters

flambda	The parallel function to be launched.
cdata	The closure data.
num_task	Number of tasks to launch, can be 0, means launch with all available threads.

Returns

0 when no error is thrown, -1 when failure happens

TVMBackendSetDevice()

TVM_RUNTIME_DLL int TVMBackendSetDevice	(	int	device_type,
		int	device_index
	)

Select the runtime device for the calling host thread.

Dispatches to DeviceAPI::SetDevice with the given local DLPack device type and runtime device index (DLDevice::device_id). This does not save or restore the previous selection. Backends without device-selection state may treat selection as a no-op. Valid indices and index validation are backend-specific.

Parameters

device_type	Local DLPack device type, not an RPC session-encoded type.
device_index	Nonnegative runtime device index, not a device type or target configuration index.

Returns

0 on success, -1 on invalid arguments, unavailable backend, or backend failure. Failure records the raised TVM FFI error on the calling thread; no C++ exception crosses this C entry point.