Demo of running CUDA programs on GPU and potential speed-up over CPU ITCS 6/8010 CUDA Programming, UNC-Charlotte, B. Wilkinson, Jan 10, 2011

2 Xclock running on client PC Xclock running on coit- grid01.uncc.edu Xclock running on coit- grid06.uncc.edu Xterm running on client PC, logged onto coit-grid06.uncc.edu Typical user interface (using a Windows PC) WinSCP running on client PC connected to grid01.uncc.edu To make sure all X servers running

3 Heat distribution problem (Solving Laplace’s equation) 800 x 800 points with 2000 iterations Speed-up = 21.2 (Not sufficiently converged) Fireplace

4 800 x 800 points iterations Different GPU block structure Speed-up = Fireplace

5 200 x 200 points with iterations Different GPU block structure Speed-up = 3.9 Fireplace

6 Potential speed-up Speed-up factor = Execution time on CPU Execution using GPU One can get one or two orders of magnitude speed up just by using a single GPU!! But it will take care to achieve large speed-ups. Algorithm used on GPU may be different to that used on CPU because of constraints on GPU, so should really compare best sequential version on CPU with algorithm used on GPU

7 N Body problem

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Questions