1 Reply Latest reply on Nov 24, 2009 12:17 PM by omkaranathan

    clEnqueueRead/WriteBuffer Performance Issue on HD5750

    kazuki

      I use clEnqueueRead/WriteBuffer with blocking mode on Radeon HD 5750.
      But wrute throughput is lower than result of PCIeSpeedTest(ATI Stream Power Toys).
      And read throughput is very lower than write throughput. why ?

      Test pseudocode:
        size = 1024*1024*64;
        NUM_TIMING_LOOPS = 100;
        buf = clCreateBuffer(context,CL_MEM_READ_WRITE,size,NULL,&errcode);
        stopwatch.start (); // use PerformanceCounter
        for (int i = 0; i < NUM_TIMING_LOOPS; i ++)
          clEnqueueWriteBuffer(queue,buf,CL_TRUE,0,size,ptr,0,NULL,NULL);
        stopwatch.stop ();
        printf (...);

      Result:
        write: 2.575GB/s
        read: 1.197GB/s

      PCIeSpeedTestResult (v0.2):
      [  67108864 bytes] CPU->GPU=   4.851 GB/sec, GPU->CPU= 861.791 MB/sec