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APU Zero Copy Support

Question asked by jmaxg3 on Jan 11, 2013
Latest reply on Jan 23, 2013 by himanshu.gautam

I've been doing some reading on zero copy support in the shared memory of CPU and GPU, and I have two questions raised by different forum posts I've seen.

 

1. Is this supported on Linux? According to http://devgurus.amd.com/thread/158885 it wasn't in March in 2.6.

 

2. How much of an impact do the read-write permission flags passed to clCreateBuffer and clEnqueueMapBuffer/clEnqueueUnmapMemObject have on performance? The post at http://blogs.amd.com/developer/2011/08/01/cpu-to-gpu-data-transfers-exceed-15gbs-using-apu-zero-copy-path/ only discusses using CL_MEM_READ_ONLY, so does that mean it's generally only considered useful if the memory object in question is read-only on GPU and written on host side?

 

Thanks in advance for any insight.

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