Performance of reduction kernel

Discussion created by delgadom on Jun 18, 2008
Latest reply on Jun 19, 2008 by delgadom

I am benchmarking the AMD stream SDK v1.1 with my Radeon HD2400 using thesamples shipped with brook+. Performance is awesone except for the tests using the reduction kernels. For example, setting


and the call to the compiled example as

./reduction -t -x 1024 -y 1024 -i 100

results in a execution time of 0.024000s. However with the same call after seeting


the time increases to 1.218000s, and the load in the CPU is not negligible.

Is the reduction buffer implemented for my Radeon? If yes, do you have any idea of how to increase the performance of the reduction?