Abstract: MPI collective communication operation is widely used in parallel scientific application, which has an important influence impact on the scalability of the program. Tianhe interconnect network supports the trigger communication operations, 
which can offload the messaging and processing work and improve the performance between nodes. Allreduce and Reduce 
algorithms under different tree topological structures are designed by using the triggered operations to lower the latency the reduction operation communication between nodes. Tests based on the actual system platform show that that, compared with the pointtopoint implementation of these two types of operations in MPICH, the offload algorithm based on trigger can reduce the running time by up to 59.6% at different node scales.

Key words: collective communication, reduction, triggered operations, offloaded communication