I’m following this tutorial 9 to try out NNAPI support in PyTorch Mobile on Pixel 3a (Android 10, Qualcomm Snapdragon 670). I compiled the speed benchmark binary off commit ID 4ed7f36ed
The commands I used are:

adb shell /data/local/tmp/speed_benchmark_torch --pthreadpool_size=1 --model=/data/local/tmp/mobilenetv2-quant_full-nnapi.pt --use_bundled_input=0 --warmup=5 --iter=200
adb shell /data/local/tmp/speed_benchmark_torch --pthreadpool_size=1 --model=/data/local/tmp/mobilenetv2-quant_full-cpu.pt --use_bundled_input=0 --warmup=5 --iter=200

Here are the benchmark numbers I got:
Quant mobilenet v2 using CPU: 66.8 ms
Quant mobilenet v2 using NNAPI: 171 ms
NNAPI not only did not accelerate the model, but slowed it down significantly. I’m really curious what I’m missing here.