Host Memory Bandwidth XRT (XRT Native API’s)

This is host memory bandwidth example to describe host memory and kernel bandwidth test using native xrt api’s.

KEY CONCEPTS: host memory, bandwidth, address translation unit

KEYWORDS: host_only, HOST[0]

This is a host application to test Host Memory bandwidth. It contains 3 kernels namely read_bandwidth, write_bandwidth and bandwidth (for concurrent read and write).The host application runs all 3 kernels with variable buffer sizes and measures the bandwidth for each case. Finally the design reports the maximum bandwidth achieved for each case.

The host allocates a buffer into specific host-only buffer using host_only flag.

xrt::bo::flags flags = xrt::bo::flags::host_only;
auto hostonly_bo_in = xrt::bo(device, bufsize, flags, krnl.group_id(0));
auto hostonly_bo_out = xrt::bo(device, bufsize, flags, krnl.group_id(1));

Using the sp option in the krnl_bandwidth.cfg file, AXI-Master Port is connected to the Slave-Bridge IP:

sp=bandwidth_1.input0:HOST[0]
sp=bandwidth_1.output0:HOST[0]
sp=read_bandwidth_1.input0:HOST[0]
sp=write_bandwidth_1.output0:HOST[0]

Following is the real log reported while running the design on U250 platform:

Open the device0
Load the xclbin ./build_dir.hw.xilinx_u250_gen3x16_xdma_3_1_202020_1/bandwidth.xclbin
Concurrent Read and Write Throughput = 7.48369 (GB/sec) for buffer size 4.00 KB
Read Throughput = 0.000335063 (GB/sec) for buffer size 4.00 KB
Write Throughput = 0.000344473 (GB/sec) for buffer size 4.00 KB

Concurrent Read and Write Throughput = 7.33095 (GB/sec) for buffer size 8.00 KB
Read Throughput = 0.000665857 (GB/sec) for buffer size 8.00 KB
Write Throughput = 0.000693077 (GB/sec) for buffer size 8.00 KB

Concurrent Read and Write Throughput = 8.49993 (GB/sec) for buffer size 16.00 KB
Read Throughput = 0.00154943 (GB/sec) for buffer size 16.00 KB
Write Throughput = 0.0015804 (GB/sec) for buffer size 16.00 KB

Concurrent Read and Write Throughput = 12.4713 (GB/sec) for buffer size 32.00 KB
Read Throughput = 0.00397313 (GB/sec) for buffer size 32.00 KB
Write Throughput = 0.0040426 (GB/sec) for buffer size 32.00 KB

Concurrent Read and Write Throughput = 15.8589 (GB/sec) for buffer size 64.00 KB
Read Throughput = 0.00929847 (GB/sec) for buffer size 64.00 KB
Write Throughput = 0.00944232 (GB/sec) for buffer size 64.00 KB

Concurrent Read and Write Throughput = 18.7322 (GB/sec) for buffer size 128.00 KB
Read Throughput = 0.0202977 (GB/sec) for buffer size 128.00 KB
Write Throughput = 0.0203858 (GB/sec) for buffer size 128.00 KB

Concurrent Read and Write Throughput = 20.2429 (GB/sec) for buffer size 256.00 KB
Read Throughput = 0.0397041 (GB/sec) for buffer size 256.00 KB
Write Throughput = 0.0429825 (GB/sec) for buffer size 256.00 KB

Concurrent Read and Write Throughput = 21.1149 (GB/sec) for buffer size 512.00 KB
Read Throughput = 0.0783758 (GB/sec) for buffer size 512.00 KB
Write Throughput = 0.0869292 (GB/sec) for buffer size 512.00 KB

Concurrent Read and Write Throughput = 21.7278 (GB/sec) for buffer size 1.00 MB
Read Throughput = 0.156576 (GB/sec) for buffer size 1.00 MB
Write Throughput = 0.177042 (GB/sec) for buffer size 1.00 MB

Concurrent Read and Write Throughput = 21.8723 (GB/sec) for buffer size 2.00 MB
Read Throughput = 0.30943 (GB/sec) for buffer size 2.00 MB
Write Throughput = 0.356215 (GB/sec) for buffer size 2.00 MB

Concurrent Read and Write Throughput = 22.0848 (GB/sec) for buffer size 4.00 MB
Read Throughput = 0.615448 (GB/sec) for buffer size 4.00 MB
Write Throughput = 0.720843 (GB/sec) for buffer size 4.00 MB

Concurrent Read and Write Throughput = 22.4699 (GB/sec) for buffer size 8.00 MB
Read Throughput = 1.26089 (GB/sec) for buffer size 8.00 MB
Write Throughput = 1.4473 (GB/sec) for buffer size 8.00 MB

Concurrent Read and Write Throughput = 14.6714 (GB/sec) for buffer size 16.00 MB
Read Throughput = 2.71928 (GB/sec) for buffer size 16.00 MB
Write Throughput = 2.84091 (GB/sec) for buffer size 16.00 MB

Concurrent Read and Write Throughput = 13.6195 (GB/sec) for buffer size 32.00 MB
Read Throughput = 5.44235 (GB/sec) for buffer size 32.00 MB
Write Throughput = 5.74132 (GB/sec) for buffer size 32.00 MB

Concurrent Read and Write Throughput = 12.6072 (GB/sec) for buffer size 64.00 MB
Read Throughput = 11.0016 (GB/sec) for buffer size 64.00 MB
Write Throughput = 11.3533 (GB/sec) for buffer size 64.00 MB

Maximum bandwidth achieved :
Concurrent Read and Write Throughput = 22.4699 (GB/sec)
Read Throughput = 11.0016 (GB/sec)
Write Throughput = 11.3533 (GB/sec)

TEST PASSED

EXCLUDED PLATFORMS

Platforms containing following strings in their names are not supported for this example :

_u25_
u30
u50lv
u50_gen3x4
zc
vck
aws
2019
2018
samsung
_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/bandwidth.cpp
src/host.cpp
src/read_bandwidth.cpp
src/write_bandwidth.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

./host_memory_bandwidth_xrt -x <bandwidth XCLBIN>