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 reduction.br 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?