diff --git a/imperative/src/impl/interpreter/interpreter_impl.cpp b/imperative/src/impl/interpreter/interpreter_impl.cpp
index 738627bb506e7d214fc5ae9c28c63bbf2c5b0d3c..173ac65b7e4cc42f0b3f81ce1f1433253f89cfc2 100644
--- a/imperative/src/impl/interpreter/interpreter_impl.cpp
+++ b/imperative/src/impl/interpreter/interpreter_impl.cpp
@@ -238,7 +238,6 @@ void ChannelImpl::dispatch_default_cpu(
     MGB_RECORD_EVENT(ShapeInferEvent, validated);
 
     SmallVector<DeviceTensorND> input_tensornds;
-    input_tensornds.reserve(input_descs.size());
     CompNode output_cn;
     {
         MGB_LOCK_GUARD(m_mutex);
@@ -261,9 +260,7 @@ void ChannelImpl::dispatch_default_cpu(
         }
     }
 
-    outputs->reserve(output_descs.size());
     SmallVector<DeviceTensorND> output_tensornds;
-    output_tensornds.reserve(output_descs.size());
     for (auto&& desc : output_descs) {
         // TODO: may conflict with condtake, which need alloc inside
         mgb_assert(!desc.layout.is_empty());
@@ -290,7 +287,6 @@ void ChannelImpl::dispatch_default_cpu(
     }
 
     SmallVector<TensorInfo*> output_infos;
-    output_infos.reserve(output_descs.size());
     for (auto&& tensornd : output_tensornds) {
         HostTensorND host_tensornd =
                 HostTensorND::make_proxy(tensornd).proxy_to_comp_node(output_cn);
@@ -329,9 +325,6 @@ void ChannelImpl::dispatch_kernel(
 
     ApplyOp cmd{Profiler::next_id(), std::move(op)};
     cmd.inputs = std::move(input_infos);
-    cmd.outputs.reserve(output_descs.size());
-    outputs->reserve(output_descs.size());
-
     for (int i = 0; i < output_descs.size(); ++i) {
         auto&& desc = output_descs[i];
         auto info = alloc();
@@ -399,9 +392,7 @@ SmallVector<Handle> ChannelImpl::apply_op_impl(
                 i);
     }
     SmallVector<TensorInfo*> input_infos;
-    input_infos.reserve(inputs.size());
     SmallVector<LogicalTensorDesc> input_descs;
-    input_descs.reserve(inputs.size());
     {
         MGB_LOCK_GUARD(m_mutex);
         for (auto i : inputs) {
diff --git a/imperative/src/impl/ops/tensor_manip.cpp b/imperative/src/impl/ops/tensor_manip.cpp
index ec560303448a4da2d0254dede59330a188e59b9e..413e1d8ce0af0622d64f3049b28b8691d3355209 100644
--- a/imperative/src/impl/ops/tensor_manip.cpp
+++ b/imperative/src/impl/ops/tensor_manip.cpp
@@ -87,7 +87,6 @@ void apply_on_device_tensornd(
 HostTensorND get_var_shape_host_tensor(
         const OpDef& def, const SmallVector<TensorPtr>& inputs) {
     SmallVector<DeviceTensorND> input_tensornds;
-    input_tensornds.reserve(inputs.size());
     for (auto&& inp : inputs) {
         input_tensornds.push_back(inp->dev_tensor());
     }
diff --git a/imperative/src/impl/proxy_graph.cpp b/imperative/src/impl/proxy_graph.cpp
index 4c8aac459d2f371087601fbc0156c52f63eb2808..8248c6946280f4263792eb98eeba806d841c9c41 100644
--- a/imperative/src/impl/proxy_graph.cpp
+++ b/imperative/src/impl/proxy_graph.cpp
@@ -232,7 +232,6 @@ public:
 
         // fill args for infer_func
         cg::static_infer::InpVal args{1};
-        args.val.reserve(desc->deps.size());
         auto push_shape = [&args](const TensorShape* shape) {
             args.val.emplace_back();
             args.val.back().m_shape = shape;
@@ -607,8 +606,6 @@ EncodedSubgraph ProxyGraph::make_backward_graph(
     }
 
     // set backward graph inputs
-    igraph.inputs.reserve(nr_backward_graph_inputs);
-    result.input_mask.reserve(nr_backward_graph_inputs);
     auto write_inputs = [&igraph, &var2idx, &result](const VarNodeArray& vars) {
         for (auto&& i : vars) {
             auto&& iter = var2idx.find(i);
diff --git a/imperative/src/impl/proxy_graph/mini_graph.h b/imperative/src/impl/proxy_graph/mini_graph.h
index 69ba85df1ef136f61ae5d45bf20742571cfb6229..a6d584604d1d27fe82bc8e02ad0e949e6f4d85d0 100644
--- a/imperative/src/impl/proxy_graph/mini_graph.h
+++ b/imperative/src/impl/proxy_graph/mini_graph.h
@@ -132,7 +132,6 @@ protected:
             mgb_assert(!infer_func);
             infer_func = func;
             inp_val.val.resize(dep_val.size());
-            deps.reserve(dep_val.size());
 
             for (auto&& dep : dep_val) {
                 auto [found, i] = find_index(opr->input(), dep.dest);
@@ -253,7 +252,6 @@ public:
 
         // fix permuted input: the order of m_opr->input() and vinputs may be
         // different, input_remap keeps the index map of m_opr->input() and vinputs
-        input_remap.reserve(m_opr->input().size());
         for (auto* v : m_opr->input()) {
             auto [found, i] = find_index(vinputs, v);
             mgb_assert(found);
@@ -272,7 +270,6 @@ public:
         }
 
         // fix permuted output
-        output_remap.reserve(ovars.size());
         for (auto* v : ovars) {
             auto [found, i] = find_index(m_opr->output(), v);
             mgb_assert(found);
@@ -784,7 +781,6 @@ public:
         auto sess = minigraph.infer_session(inputs);
         std::tuple<SmallVector<LogicalTensorDesc>, bool> ret;
         auto& [descs, noerr] = ret;
-        descs.reserve(minigraph.output_size());
         for (size_t i = 0; i < minigraph.output_size(); ++i) {
             descs.emplace_back();
             auto& desc = descs.back();
@@ -819,7 +815,6 @@ public:
             mgb_assert(shape);
             minigraph.opr()->output()[i]->shape(*shape);
         }
-        descs.reserve(minigraph.output_size());
         for (size_t i = 0; i < minigraph.output_size(); ++i) {
             auto* ovar = minigraph.output_var(i);
             mgb_assert(ovar->dtype().valid() && ovar->comp_node().valid());