4 Replies Latest reply on Jul 23, 2011 8:58 AM by pinzo

    problem with tranfer time

    pinzo

      hi,

      I notice that increasing the dimension of the buffer I transfer from CPU to GPU, in the transfer time appear a structure with a double peak far one from the other which one of the peaks agree with the transfer time of lower buffer. The peak that appear, instead is shifted to time 4 time bigger than normal.

      I don't understand with with the same data  sometimes we have the correct transfer time while sometimes we have 4 time bigger.

      nobody see something like it?

      thanks

        • problem with tranfer time
          himanshu.gautam

          Hi Pizo,

          Can you please explain in short sentences, I am not able to understand the problem.

            • problem with tranfer time
              pinzo

              In this picture you can se the trasfer time increasing the number of events I process with the GPU (directly proporzional to buffer dimension). How can you see at 10000 events the cpu->gpu mean time increase very much and it have an huge error. This Is due at the presence, only for more than 10000 events, of two popolations of trasfer time: one with mean lower tha 200 microsecond and the other with mean greater than 1ms. I don't understand why some repetition have transfer time about 1ms and someone about 200 microsecond if the imput data is the same for all the repetition?

              thanks very much

              transfer time