1 Reply Latest reply on Mar 15, 2011 4:28 AM by himanshu.gautam

    Stream Timeline

      How to use the Stream Timeline in Visual Studio

      A simple question.

      I collect application trace and the stream timeline displayed information as below. (GPU Radeon HD 5870)

      Data Transfer:

      Name:12.0 KB READ_BUFFER


      Command Type: CL_COMMAND_READ_BUFFER

      Queued Time:2704.881 millisecond

      Submit Time:2704.891 millisecond

      Start Time:2705.210 millisecond

      End Time: 2705.295 millisecond

      Duration: 85.280 microseconds

      clEnqueue API Name: clEnqueueReadBuffer

      clEnqueue API Start Time: 2704.875 millisecond

      clEnqueue API End Time: 2705.333 millisecond

      clEnqueue API Duration: 458.259 microseconds

      Transfer Rate: 137.415 MB/s

      Transfer Size: 12.000 KB


      Why the transfer rate only 137.415 MB/s? Any comment about this?


        • Stream Timeline


          You should try to copy a larger chunk of data. Also do that multiple times and then calculate the Transfer rate.

          There can be a lot of reasons for such transfer rate including GPU warm-up times, memory access pattern, and channel conflicts. You can refer to the GLobal Memory Bandwidth Sample to know how to get better memory transfer rates.