AllocMessage

Applicability

Product	Supported
Atlas 350 Accelerator Card	√
Atlas A3 training product / Atlas A3 inference product	x
Atlas A2 training product / Atlas A2 inference product	√
Atlas 200I/500 A2 inference product	x
Atlas inference product AI Core	x
Atlas inference product Vector Core	x
Atlas training product	x

Function Usage

Allocates message space in a message queue requested by the AIV, which is used to store message structures. The address of the current message space is returned. The depth of the message queue is fixed to 4. The allocation of message space follows a specific order (e.g., top-down, then looping back). When the message space to which the message queue pointer points is in the FREE state, AllocMessage returns the address of the space. Otherwise, AllocMessage loops until the current space is in the FREE state.

Figure 1 AllocMessage

Prototype

      
           template <PipeMode pipeMode = PipeMode::SCALAR_MODE>             
__aicore__ inline __gm__ CubeMsgType *AllocMessage()

Parameters

Table 1 Template parameters

Parameter

Description

pipeMode

Execution unit for sending messages. The PipeMode type is defined as follows:

           
                enum class PipeMode : uint8_t { 
  SCALAR_MODE = 0, // Uses the Scalar execution unit to write messages to the global memory.
  MTE3_MODE = 1, // Uses the MTE3 unit to write messages to the global memory.
  MAX 
}

Note that if pipeMode is set to MTE3_MODE, only the PostMessage API can be used to send messages. In addition, the template parameter pipeMode of the AllocMessage and PostMessage APIs must be the same.

Returns

Address of the message space that is currently allocated for

Restrictions

None

Example

      
           auto queIdx = AscendC::GetBlockIdx();
handle.AssignQueue(queIdx);
auto msgPtr = handle.AllocMessage();        // After a queue is bound, allocate message space in the queue. The message space address is msgPtr.

Parent topic: CubeResGroupHandle