FetchEventID

Applicability

Product	Supported/Unsupported
Atlas A3 training products / Atlas A3 inference products	√
Atlas A2 training products / Atlas A2 inference products	√
Atlas 200I/500 A2 inference products	x
Atlas inference product 's AI Core	√
Atlas inference product 's Vector Core	x
Atlas training products	√

Function Usage

Obtains available TEventIDs based on HardEvent (hardware synchronization event). This API does not allocate TEventIDs, but provides available TEventIDs.

Prototype

      
           template <HardEvent evt>
__aicore__ inline TEventID FetchEventID()
__aicore__ inline TEventID FetchEventID(HardEvent evt)

Parameters

Parameter	Input/Output	Meaning
evt	Input	HardEvent hardware synchronization type. For details about this type, see the description of synchronization types in the SetFlag/WaitFlag(ISASI).

Parameter

Input/Output

Meaning

evt

Input

HardEvent hardware synchronization type.

For details about this type, see the description of synchronization types in the SetFlag/WaitFlag(ISASI).

Restrictions

Compared with AllocEventID, FetchEventID is applicable to the scenario where IDs are temporarily used. After an ID is obtained, the ID is not occupied. In some complex application scenarios, you need to ensure that the usage is correct. For example, if SetFlag and WaitFlag are called consecutively in the same pipeline and the two IDs are obtained using FetchEventID, undefined behaviors such as program suspension may occur because the two IDs are the same. In this case, AllocEventID is recommended.

Returns

TEventID

Example

      
           AscendC::TEventID eventIdVToS = GetTPipePtr()->FetchEventID(AscendC::HardEvent::V_S); //The scalar needs to wait for vector synchronization and the HardEvent ID is required.
AscendC::SetFlag<AscendC::HardEvent::V_S>(eventIdVToS);
AscendC::WaitFlag<AscendC::HardEvent::V_S>(eventIdVToS);

Parent topic: TPipe