[Tests/Docs] Set SWG to HLS for depthwise conv cppsim tests

CONTRIBUTING.md

@@ -73,7 +73,9 @@ Please use the *Signed-off-by* line at the end of your patch which indicates tha
       this project or the open source license(s) involved.
 ```
 
-Here is an example Signed-off-by line which indicates that the contributor accepts DCO::
+You can enable Signed-off-by automatically by adding the `-s` flag to the `git commit` command.
+
+Here is an example Signed-off-by line which indicates that the contributor accepts DCO:
 
 ```
   This is my commit message

tests/fpgadataflow/test_depthwise_convolution.py

@@ -182,6 +182,12 @@ def test_depthwise_conv_hw_cppsim(act, pe, k, stride, padding):
     new_model = model.transform(InferConvInpGen())
     new_model = new_model.transform(InferVectorVectorActivation())
 
+    # CPPsim of RTL SWG defaults to Im2Col emulation which has no concept
+    # of parallelism. So, we're using the HLS-SWG for cppsim testing for now.
+    # Set preferred_impl_style to hls to instantiate HLS-SWG
+    swg_nodes = new_model.get_nodes_by_op_type("ConvolutionInputGenerator")[0]
+    getCustomOp(swg_nodes).set_nodeattr("preferred_impl_style", "hls")
+
     new_model = new_model.transform(SpecializeLayers())
 
     # set SIMD in ConvInputGen node and PE in VVAU node