Slave Bridge Copy Buffer¶
This is simple slave bridge example to describe how host-only memory can be copied to device-only memory and vice-versa.
KEY CONCEPTS: slave bridge
KEYWORDS: XCL_MEM_EXT_HOST_ONLY, CL_MEM_HOST_NO_ACCESS, enqueueCopyBuffer
This example illustrates how host only memory can be copied to device only memory and vice-versa using EnqueueCopyBuffer
API.
Host only buffer is created using XCL_MEM_EXT_HOST_ONLY
flag whereas device only buffer is created using CL_MEM_HOST_NO_ACCESS
flag. The following data transfers take place in the example -
Copy the HOST_ONLY input buffer
buffer_in_host
into DEVICE_ONLY input bufferbuffer_in_dev
using M2M.
OCL_CHECK(err,
err = q.enqueueCopyBuffer(buffer_in_host_a, buffer_in_dev_a, 0, 0,
size_in_bytes, 0, nullptr)); // transfer
OCL_CHECK(err,
err = q.enqueueCopyBuffer(buffer_in_host_b, buffer_in_dev_b, 0, 0,
size_in_bytes, 0, nullptr)); // transfer
Enqueue kernel to do computations on DEVICE_ONLY input buffer
buffer_in_dev
and put output in DEVICE_ONLY output bufferbuffer_out_dev
.
q.enqueueTask(krnl);
Copy the DEVICE_ONLY output buffer
buffer_out_dev
into HOST_ONLY output bufferbuffer_out_host
using M2M.
OCL_CHECK(err,
err = q.enqueueCopyBuffer(buffer_out_dev, buffer_out_host, 0, 0,
size_in_bytes, 0, nullptr)); // transfer
EXCLUDED PLATFORMS¶
Platforms containing following strings in their names are not supported for this example :
_u25_
u30
u50c
u50lv
u50_gen3x4
u55
u250
zc
vck
aws-vu9p-f1
2019
2018
_u2_
DESIGN FILES¶
Application code is located in the src directory. Accelerator binary files will be compiled to the xclbin directory. The xclbin directory is required by the Makefile and its contents will be filled during compilation. A listing of all the files in this example is shown below
src/host.cpp
src/krnl_vadd.cpp
Access these files in the github repo by clicking here.
COMMAND LINE ARGUMENTS¶
Once the environment has been configured, the application can be executed by
./slave_bridge_copy_buffer.exe <krnl_vadd XCLBIN>