Design of Kernel-Level Asynchronous Collective Communication.

Overlapping computation and communication, not only point-to-point but also collective communications, is an important technique to improve the performance of parallel programs. Since the current non-blocking collective communications have been mostly implemented using an extra thread to progress communication, they have extra overhead due to thread scheduling and context switching. In this paper, a new non- blocking communication facility, called KACC is proposed to provide fast asynchronous collective communications. KACC is implemented in the OS kernel interrupt context to perform non-blocking asynchronous collective operations without an extra thread. The experimental results show that the CPU time cost of this method is sufficiently small. [ABSTRACT FROM AUTHOR]