![]() Produce 15-45% speedup over best UPC Blocking version.Berkeley UPC compiler support non-blocking UPC extensions.Example Message Size Breakdown for Class D at 256 Threads.Do column FFTs, then row FFTs on first row, send it, repeat for each row and each slabĭecomposing NAS FT Exchange into Smaller Messages.When done with xy, wait for and start on z.Do column FFTs, then row FFT on first slab, then send it, repeat.Do column/row FFTs, then send 1/pth of data to each, do z FFTs.Several implementations, each processor owns a set of xy slabs (planes).Separate computation and communication phases Transpose + 1D-FFT (Rows) 1D-FFT (Columns) Cachelines 1D-FFT Rows send to Thread 0 Exchange (Alltoall) Transpose + 1D-FFT send to Thread 1 Divide rows among threads send to Thread 2 Last 1D-FFT (Thread 0’s view).Single Communication Operation (Global Exchange) sends THREADS large messages.Spread communication out over longer period of time: “All the wires all the time” Default NAS FT Fortran/MPI relies on #1 Our approach builds on #2ģD FFT Operation with Global Exchange 1D-FFT Columns Use a better network (higher Bisection BW) 2. Between 30-40% of the applications total runtime.Becoming more expensive as # processors grows. ![]()
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