Mutex emulation for MPI
This mutex is aimed to lock a specific remote memory (RM), say rank 0. This means that the boolean that acts as a mutex is located in a specific rank. However, when a critical section is acquired, any other communication can be process-safe.
Then, be sure of creating a communicator and window that will be used with the corresponding ranks. If all ranks will have to syncrhonised with the RM at rank 0, then it can be any world_communicator.
To allocate use it this way.
MPI_Mutex mpi_mutex;
MPI_Comm mutex_Comm;
MPI_Win win_mutex;
MPI_Comm_dup(MPI_COMM_WORLD, &mutex_Comm);
if (world_rank == 0)
{
// mpi mutex **********************************************************************************************
MPI_Win_allocate(sizeof(bool), sizeof(bool), MPI::INFO_NULL, mutex_Comm, &mpi_mutex.mutex, &win_mutex);
// ********************************************************************************************************
mpi_mutex.mutex[0] = false; // initialization
}
else
{
// it is not required to allocate buffer memory for the other processes
// mpi mutex **********************************************************************************************
MPI_Win_allocate(0, sizeof(bool), MPI::INFO_NULL, mutex_Comm, &mpi_mutex.mutex, &win_mutex);
// ********************************************************************************************************
}
mpi_mutex.set(mutex_Comm, win_mutex); // mutex initialization to use it, where all participant ranks are able to reach it.
// RM in rank 0
mpi_mutex.lock(0);
/*
critical section
*/
mpi_mutex.unlock(0);It might be conflicting depending on the ucx server configurations.
I'd appreciate any comment.
That's all folks