[VTA][HotFix] Relay->VTA quantization fix (#4433)

* relay -> vta fix

* setting optlevel to 3 for quantization to fold batchnorm

vta/scripts/tune_resnet.py

@@ -125,6 +125,8 @@ def compile_network(opt, env, target):
     dtype_dict.update({k: str(v.dtype) for k, v in params.items()})
 
     # Perform quantization in Relay
+    # Note: We set opt_level to 3 in order to fold batch norm
+    with relay.build_config(opt_level=3):
         with relay.quantize.qconfig(global_scale=8.0,
                                     skip_conv_layers=[0]):
             relay_prog = relay.quantize.quantize(mod["main"], params=params)

vta/tutorials/autotvm/tune_relay_vta.py

@@ -89,15 +89,17 @@ def compile_network(env, target, model, start_pack, stop_pack):
     dtype_dict.update({k: str(v.dtype) for k, v in params.items()})
 
     # Perform quantization in Relay
+    # Note: We set opt_level to 3 in order to fold batch norm
+    with relay.build_config(opt_level=3):
         with relay.quantize.qconfig(global_scale=8.0,
                                     skip_conv_layers=[0]):
-        relay_prog = relay.quantize.quantize(mod["main"], params=params)
+            mod = relay.quantize.quantize(mod, params=params)
 
     # Perform graph packing and constant folding for VTA target
     if target.device_name == "vta":
         assert env.BLOCK_IN == env.BLOCK_OUT
         relay_prog = graph_pack(
-            relay_prog,
+            mod["main"],
             env.BATCH,
             env.BLOCK_OUT,
             env.WGT_WIDTH,

vta/tutorials/frontend/deploy_vision_on_vta.py

@@ -168,13 +168,15 @@ with autotvm.tophub.context(target):
 
     if target.device_name == "vta":
         # Perform quantization in Relay
+        # Note: We set opt_level to 3 in order to fold batch norm
+        with relay.build_config(opt_level=3):
             with relay.quantize.qconfig(global_scale=8.0,
                                         skip_conv_layers=[0]):
-            relay_prog = relay.quantize.quantize(mod["main"], params=params)
+                mod = relay.quantize.quantize(mod, params=params)
             # Perform graph packing and constant folding for VTA target
             assert env.BLOCK_IN == env.BLOCK_OUT
             relay_prog = graph_pack(
-            relay_prog,
+                mod["main"],
                 env.BATCH,
                 env.BLOCK_OUT,
                 env.WGT_WIDTH,