There is no such option for MPICH. If you configure with ch3:sock, which waits for the progress with blocking `poll`, I think it will not hog the CPU by default, for other configurations, it always busy waits. Is using MPI_Iprobe + MPI_Test an option for you? If your process can afford latency, then you can control your own sleep cycles between MPI_Test. If MPICH will implement such non-busy-wait option, internally it will just do the same test-sleep cycles. -- Hui Zhou From: "Mccall, Kurt E. (MSFC-EV41) via discuss" <[email protected]> Reply-To: "[email protected]" <[email protected]> Date: Wednesday, June 3, 2020 at 3:57 PM To: "[email protected]" <[email protected]> Cc: "Mccall, Kurt E. (MSFC-EV41)" <[email protected]> Subject: [mpich-discuss] Controlling MPICH busy-wait behavior Is there a means to tell MPICH to yield to other processes when performing a busy-wait for incoming messages? The page below distinguishes between “aggressive busy-wait” and “degraded busy-wait”, where the latter is what I’d like to try. https://stackoverflow.com/questions/14560714/probe-seems-to-consume-the-cpu/... Thanks, Kurt