diff --git a/src/03runtime/include/runtime/stream.h b/src/03runtime/include/runtime/stream.h
index 4e3bfe30..6b8e58a1 100644
--- a/src/03runtime/include/runtime/stream.h
+++ b/src/03runtime/include/runtime/stream.h
@@ -49,7 +49,7 @@ namespace refactor::runtime {
         auto prepare() -> std::vector<count_t>;
         void run();
         auto bench(void (*sync)()) -> std::vector<std::chrono::nanoseconds>;
-        void trace(std::function<void(count_t, void const **, void **)>);
+        void trace(std::function<void(count_t, void const *const *, void const *const *)>);
     };
 
 }// namespace refactor::runtime
diff --git a/src/03runtime/src/stream.cc b/src/03runtime/src/stream.cc
index 2c6fe884..05228da9 100644
--- a/src/03runtime/src/stream.cc
+++ b/src/03runtime/src/stream.cc
@@ -96,7 +96,6 @@ namespace refactor::runtime {
     }
 
     void Stream::run() {
-        auto map = [this](auto i) { return _internal.edges[i](*_stack); };
         std::vector<void *> buffer(16);
         for (auto const [nodeIdx, i, o] : _internal.topology) {
             auto [inputs, outputs] = collectAddress(*_stack, _internal.edges, buffer, i, o);
@@ -105,7 +104,6 @@ namespace refactor::runtime {
     }
 
     auto Stream::bench(void (*sync)()) -> std::vector<std::chrono::nanoseconds> {
-        auto map = [this](auto i) { return _internal.edges[i](*_stack); };
         std::vector<void *> buffer(16);
         std::vector<std::chrono::nanoseconds> ans(_internal.nodes.size());
         for (auto const [nodeIdx, i, o] : _internal.topology) {
@@ -119,8 +117,7 @@ namespace refactor::runtime {
         return ans;
     }
 
-    void Stream::trace(std::function<void(count_t, void const **, void **)> record) {
-        auto map = [this](auto i) { return _internal.edges[i](*_stack); };
+    void Stream::trace(std::function<void(count_t, void const *const *, void const *const *)> record) {
         std::vector<void *> buffer(16);
         for (auto const [nodeIdx, i, o] : _internal.topology) {
             auto [inputs, outputs] = collectAddress(*_stack, _internal.edges, buffer, i, o);
diff --git a/src/07onnx/src/operators.cpp b/src/07onnx/src/operators.cpp
index cc25b712..20598ab4 100644
--- a/src/07onnx/src/operators.cpp
+++ b/src/07onnx/src/operators.cpp
@@ -34,7 +34,7 @@
 namespace refactor::onnx {
 
     void register_() {
-// clang-format off
+        // clang-format off
         #define REGISTER(NAME, CLASS) Operator::register_<CLASS>("onnx::" #NAME)
         REGISTER(BatchNormalization, BatchNormalization);
         REGISTER(Cast              , Cast              );
diff --git a/src/08communication/src/operators.cpp b/src/08communication/src/operators.cpp
index 9525588d..3f47f256 100644
--- a/src/08communication/src/operators.cpp
+++ b/src/08communication/src/operators.cpp
@@ -6,7 +6,7 @@ namespace refactor::communication {
     using namespace frontend;
 
     void register_() {
-// clang-format off
+        // clang-format off
         #define REGISTER(NAME, CLASS) Operator::register_<CLASS>("onnx::" #NAME)
         REGISTER(AllReduceAvg , AllReduce);
         REGISTER(AllReduceSum , AllReduce);
diff --git a/src/09python_ffi/src/executor.cc b/src/09python_ffi/src/executor.cc
index 0455fc28..7018f263 100644
--- a/src/09python_ffi/src/executor.cc
+++ b/src/09python_ffi/src/executor.cc
@@ -51,11 +51,13 @@ namespace refactor::python_ffi {
 
     void Executor::trace(std::string path_) {
         namespace fs = std::filesystem;
+
         auto path = fs::path(std::move(path_));
         fs::create_directories(path);
         ASSERT(fs::is_directory(path), "Failed to create \"{}\"", path.c_str());
+
         auto it = _graph.internal().contiguous().topology.begin();
-        _stream.trace([&](count_t nodeIdx, void const **inputs, void **outputs) {
+        _stream.trace([&](count_t nodeIdx, void const *const *inputs, void const *const *outputs) {
             auto [nodeIdx_, i_, o_] = *it++;
             ASSERT(nodeIdx_ == nodeIdx, "node index mismatch");
             auto nodeName = _graph.internal().contiguous().nodes[nodeIdx].name;
@@ -63,8 +65,9 @@ namespace refactor::python_ffi {
             std::replace(nodeName.begin(), nodeName.end(), '.', '-');
 
             std::vector<char> buffer;
-            auto fn = [&](char dir, count_t idx, computation::Edge const &edge, void const *ptr) {
-                if (!ptr) { return; }
+            auto fn = [&](char dir, count_t idx, count_t edgeIdx, void const *const *addresses) {
+                if (!addresses[idx]) { return; }
+                auto edge = _graph.internal().contiguous().edges[edgeIdx];
                 auto size = edge.tensor->bytesSize();
                 buffer.resize(size);
 
@@ -75,14 +78,13 @@ namespace refactor::python_ffi {
                 fs::remove(file);
                 std::ofstream os(file, std::ios::binary);
 #ifdef USE_CUDA
-                kernel::cuda::copyOut(buffer.data(), ptr, size);
+                kernel::cuda::copyOut(buffer.data(), addresses[idx], size);
 #endif
                 os.write(buffer.data(), size);
             };
 
-            auto const &edges = _graph.internal().contiguous().edges;
-            for (auto i : range0_(i_.size())) { fn('i', i, edges[i_[i]], inputs[i]); }
-            for (auto i : range0_(o_.size())) { fn('o', i, edges[o_[i]], outputs[i]); }
+            for (auto i : range0_(i_.size())) { fn('i', i, i_[i], inputs); }
+            for (auto i : range0_(o_.size())) { fn('o', i, o_[i], outputs); }
         });
     }