Hello, I have a question about pinned memory and hope that you can help me.
I found out that copying data from device to host takes a very big part of my runtime, so I read about the issue and came across "pinned memory". There are several examples on the mailing list but I am not sure if I am doing this the right way. Do I need to initialize with drv.ctx_flags.MAP_HOST or is this automatically activated if one of the functions below is used? drv.init() dev = drv.Device(0) ctx = dev.make_context(drv.ctx_flags.SCHED_AUTO | drv.ctx_flags.MAP_HOST) Is drv.mem_host_register_flags.DEVICEMAP also needed if the context is initialized with drv.ctx_flags.MAP_HOST ? I found several methods that should do this but none of them seems to work. Are they all equivalent? -- x = drv.register_host_memory(x, flags=drv.mem_host_register_flags.DEVICEMAP) x_gpu_ptr = np.intp(x.base.get_device_pointer()) -- x = drv.pagelocked_empty(shape=x.shape, dtype=np.float32, mem_flags=drv.mem_host_register_flags.DEVICEMAP) -- from pycuda.tools import PageLockedMemoryPool pool = PageLockedMemoryPool() x_ptr = pool.allocate(dest.shape , np.float32) -- If I use np.intp(x.base.get_device_pointer()) and drv.memcpy_dtoh(a_gpu, x_ptr) there is an error message "BufferError: Object is not writable." Kind regards, Joe
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