How to set target to android arm-v7 devices?

i try to run benchmark on an android devices.

"python3 arm_cpu_imagenet_bench.py --network=“mobilenet” --model=“rasp3b” --host=“0.0.0.0” --port=9090 --rpc-key=“android”

since the default device “rasp3b” target setting doesn’t match with my device, so i set target as following:
“target = “llvm -device=arm_cpu -target=arm-linux-android -mfloat-abi=soft””

However, there is still WARNING log, seems autotvm not work.

WARNING:autotvm:Cannot find config for target=llvm -device=arm_cpu -target=arm-linux-android -mfloat-abi=soft,

So how to set the target? any documents?