From f102c2bb6a2bb1933ae08e592716e7ce3cee985a Mon Sep 17 00:00:00 2001
From: Yaman Umuroglu <maltanar@gmail.com>
Date: Mon, 4 May 2020 23:46:49 +0100
Subject: [PATCH] [FIFO] only insert depth > 2 FIFOs
HLS streaming nodes already have small FIFOs at i/o
---
.../fpgadataflow/insert_fifo.py | 57 ++++++++++---------
1 file changed, 31 insertions(+), 26 deletions(-)
diff --git a/src/finn/transformation/fpgadataflow/insert_fifo.py b/src/finn/transformation/fpgadataflow/insert_fifo.py
index 9850ad7e2..95a7a7154 100644
--- a/src/finn/transformation/fpgadataflow/insert_fifo.py
+++ b/src/finn/transformation/fpgadataflow/insert_fifo.py
@@ -59,7 +59,6 @@ class InsertFIFO(Transformation):
n_output = n.output[0]
consumer = model.find_consumer(n_output)
if _suitable_node(consumer) is True:
- graph_modified = True
n0 = getCustomOp(n)
# determine fifo node attributes
fld_shape = n0.get_folded_output_shape()
@@ -84,33 +83,39 @@ class InsertFIFO(Transformation):
fifo_depth = n0_depth
elif n0_depth != n1_depth:
fifo_depth = max(n0_depth, n1_depth)
+
+ if fifo_depth > 2:
+ # assumption: HLS streaming components already have
+ # depth-2 FIFOs on inputs and outputs, so no point
+ # creating additional small FIFOs in between --
+ # we only create the larger FIFOs specified
+ # create fifo node
+ fifo_output_tensor = oh.make_tensor_value_info(
+ model.make_new_valueinfo_name(),
+ TensorProto.FLOAT,
+ n0.get_normal_output_shape(),
+ )
+ graph.value_info.append(fifo_output_tensor)
+ model.set_tensor_datatype(fifo_output_tensor.name, dtype)
+
+ fifo_node = oh.make_node(
+ "StreamingFIFO",
+ [n_output],
+ [fifo_output_tensor.name],
+ domain="finn",
+ backend="fpgadataflow",
+ depth=fifo_depth,
+ folded_shape=fld_shape,
+ dataType=str(dtype.name),
+ )
+ # insert fifo
+ graph.node.insert(node_ind + 1, fifo_node)
+ # set fifo output tensor as new input tensor of second node
+ consumer.input[0] = fifo_output_tensor.name
+ # ensure created FIFO depth is reflected on both sides
n0.set_nodeattr("outFIFODepth", fifo_depth)
n1.set_nodeattr("inFIFODepth", fifo_depth)
-
- # create fifo node
- fifo_output_tensor = oh.make_tensor_value_info(
- model.make_new_valueinfo_name(),
- TensorProto.FLOAT,
- n0.get_normal_output_shape(),
- )
- graph.value_info.append(fifo_output_tensor)
- model.set_tensor_datatype(fifo_output_tensor.name, dtype)
-
- fifo_node = oh.make_node(
- "StreamingFIFO",
- [n_output],
- [fifo_output_tensor.name],
- domain="finn",
- backend="fpgadataflow",
- depth=fifo_depth,
- folded_shape=fld_shape,
- dataType=str(dtype.name),
- )
- # insert fifo
- graph.node.insert(node_ind + 1, fifo_node)
-
- # set fifo output tensor as new input tensor of second node
- consumer.input[0] = fifo_output_tensor.name
+ graph_modified = True
if graph_modified is False:
# insert FIFO as first node
--
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