add benchmark of Raspberry Pi 4B (#447)

benchmark/README.md

@@ -224,3 +224,49 @@ tengine-lite library version: 1.0-dev
 ALL TEST DONE
 ```
 
+Raspberry Pi 4B  (Cortex-A72 1.5GHZ x 4)
+```bash
+pi@raspberrypi:~/Tengine/benchmark $ ../build/benchmark/tm_benchmark -r 8
+start to run register cpu allocator
+loop_counts = 8
+num_threads = 1
+power       = 0
+tengine-lite library version: 1.0-dev
+     squeezenet_v1.1  min =   70.35 ms   max =   72.14 ms   avg =   70.99 ms
+         mobilenetv1  min =  125.71 ms   max =  126.87 ms   avg =  126.30 ms
+         mobilenetv2  min =  124.22 ms   max =  125.28 ms   avg =  124.67 ms
+         mobilenetv3  min =   78.73 ms   max =   79.78 ms   avg =   79.10 ms
+        shufflenetv2  min =   38.69 ms   max =   39.25 ms   avg =   38.96 ms
+            resnet18  min =  219.02 ms   max =  220.24 ms   avg =  219.49 ms
+            resnet50  min =  632.10 ms   max =  633.48 ms   avg =  632.85 ms
+           googlenet  min =  264.98 ms   max =  385.50 ms   avg =  287.44 ms
+         inceptionv3  min = 1035.28 ms   max = 1060.50 ms   avg = 1039.35 ms
+               vgg16  min = 1163.56 ms   max = 1409.93 ms   avg = 1222.29 ms
+                mssd  min =  254.38 ms   max =  255.45 ms   avg =  254.99 ms
+          retinaface  min =   40.51 ms   max =   45.60 ms   avg =   41.24 ms
+         yolov3_tiny  min =  301.45 ms   max =  304.59 ms   avg =  303.26 ms
+      mobilefacenets  min =   59.49 ms   max =   60.40 ms   avg =   59.76 ms
+ALL TEST DONE
+pi@raspberrypi:~/Tengine/benchmark $ ../build/benchmark/tm_benchmark -r 8 -t 4
+start to run register cpu allocator
+loop_counts = 8
+num_threads = 4
+power       = 0
+tengine-lite library version: 1.0-dev
+     squeezenet_v1.1  min =   40.91 ms   max =   42.42 ms   avg =   41.44 ms
+         mobilenetv1  min =   54.45 ms   max =   55.20 ms   avg =   54.84 ms
+         mobilenetv2  min =   66.10 ms   max =   66.99 ms   avg =   66.39 ms
+         mobilenetv3  min =   56.95 ms   max =   57.37 ms   avg =   57.14 ms
+        shufflenetv2  min =   19.91 ms   max =   20.39 ms   avg =   20.10 ms
+            resnet18  min =  157.12 ms   max =  160.92 ms   avg =  158.37 ms
+            resnet50  min =  330.70 ms   max =  335.26 ms   avg =  332.28 ms
+           googlenet  min =  169.96 ms   max =  172.73 ms   avg =  171.61 ms
+         inceptionv3  min =  502.01 ms   max =  526.95 ms   avg =  511.20 ms
+               vgg16  min =  818.95 ms   max =  854.09 ms   avg =  839.29 ms
+                mssd  min =  110.79 ms   max =  113.91 ms   avg =  111.96 ms
+          retinaface  min =   25.39 ms   max =   42.38 ms   avg =   27.72 ms
+         yolov3_tiny  min =  188.28 ms   max =  190.19 ms   avg =  188.88 ms
+      mobilefacenets  min =   28.96 ms   max =   31.83 ms   avg =   29.59 ms
+ALL TEST DONE
+
+```