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SetFlag/WaitFlag(ISASI)

Function Usage

Synchronization instruction between different pipelines in the same core. This synchronization operation needs to be inserted between different pipeline instructions with data dependency.

Prototype

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template <HardEvent event>
__aicore__ inline void SetFlag(int32_t eventID)
template <HardEvent event>
__aicore__ inline void WaitFlag(int32_t eventID)

Parameters

Table 1 Parameters

Parameter

Input/Output

Description

event

Input

Template parameter.

Synchronization event of the HardEvent data type. For details, see the following description of synchronization types.

eventID

Input

Event ID. The data type is int32_t. The definition is as follows:

The event ID needs to be obtained through AllocEventID or FetchEventID.

Atlas Training Series Product: The value ranges from 0 to 3.

The synchronization types are described as follows:

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enum class HardEvent : uint8_t {
   // Name (source pipeline_target pipeline). For example, MTE2_V indicates that PIPE_MTE2 is the source pipeline and PIPE_V is the target pipeline. Synchronization is performed between PIPE_MTE2 and PIPE_V, and PIPE_V waits for PIPE_MTE2.
    MTE2_MTE1
    MTE1_MTE2
    MTE1_M
    M_MTE1
    MTE2_V
    V_MTE2
    MTE3_V
    V_MTE3
    M_V
    V_M
    V_V
    MTE3_MTE1
    MTE1_MTE3
    MTE1_V
    MTE2_M
    M_MTE2
    V_MTE1
    M_FIX // Not supported in the current version
    FIX_M // Not supported in the current version
    MTE3_MTE2
    MTE2_MTE3
    S_V
    V_S
    S_MTE2
    MTE2_S
    S_MTE3
    MTE3_S
    MTE2_FIX // Not supported in the current version
    FIX_MTE2 // Not supported in the current version
    FIX_S // Not supported in the current version
    M_S
    FIX_MTE3 // Not supported in the current version
}

Returns

None

Availability

Atlas Training Series Product

Constraints

  • SetFlag and WaitFlag must appear in pairs.
  • You are not allowed to specify the event ID when using SetFlag and WaitFlag. Otherwise, the event ID may conflict with the framework synchronization event, causing suspension. The event ID

    is obtained through AllocEventID or FetchEventID.

Example

DataCopy can be executed only after SetValue is executed. In this case, you need to insert the synchronization operation between PIPE_S and PIPE_MTE3.

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AscendC::GlobalTensor<half> dstGlobal;
AscendC::LocalTensor<half> dstLocal;
dstLocal.SetValue(0, 0);
uint32_t dataSize = 512;
int32_t eventIDSToMTE3 = static_cast<int32_t>(GetTPipePtr()->FetchEventID(AscendC::HardEvent::S_MTE3));
AscendC::SetFlag<AscendC::HardEvent::S_MTE3>(eventIDSToMTE3);
AscendC::WaitFlag<AscendC::HardEvent::S_MTE3>(eventIDSToMTE3);
AscendC::DataCopy(dstGlobal, dstLocal, dataSize);