[Refactor] Support batch inference with shape clustering (#1733)

* refactor `NetModule`

* name

* fix sorting

* fix indices

(cherry picked from commit f5a05b5)

Author: lzhangzz

csrc/mmdeploy/net/net_module.cpp

@@ -1,7 +1,9 @@
 // Copyright (c) OpenMMLab. All rights reserved.
 
-#include "net_module.h"
+#include "mmdeploy/net/net_module.h"
 
+#include <algorithm>
+#include <numeric>
 #include <thread>
 
 #include "mmdeploy/archive/value_archive.h"
@@ -31,6 +33,11 @@ struct NetModule::Impl {
         is_profiling_ = true;
       }
       auto model = context["model"].get<Model>();
+      for (const auto& meta : model.meta().models) {
+        if (meta.name == name) {
+          max_batch_size_ = meta.batch_size;
+        }
+      }
       OUTCOME_TRY(auto config, model.GetModelConfig(name));
       device_ = context.value("device", Device{"cpu"});
       stream_ = context.value("stream", Stream::GetDefault(device_));
@@ -78,112 +85,197 @@ struct NetModule::Impl {
     return success();
   }
 
-  Result<TensorShape> InferInputShape(const vector<Tensor>& input) {
+  static Result<TensorShape> InferBatchShape(const vector<Tensor>& input) {
     auto batch_size = input.size();
     auto& exemplar = input.front();
     auto shape = exemplar.shape();
     if (batch_size == 1) {
       return shape;
     }
     if (shape[0] != 1) {
-      MMDEPLOY_ERROR("unsupported shape for batch assemble: {}", shape);
+      MMDEPLOY_WARN("unsupported shape for batch assemble: {}", shape);
       return Status(eNotSupported);
     }
     for (int i = 1; i < input.size(); ++i) {
       auto& sample = input[i];
       if (sample.shape() != shape) {
-        MMDEPLOY_ERROR("shapes are not consistent across the batch");
+        MMDEPLOY_WARN("shapes are not consistent across the batch");
         return Status(eNotSupported);
       }
     }
     shape[0] = static_cast<int64_t>(batch_size);
     return shape;
   }
 
-  Result<vector<TensorShape> > InferInputShape(const vector<vector<Tensor> >& inputs) {
+  static Result<vector<TensorShape>> InferBatchShape(const vector<vector<Tensor>>& inputs) {
     vector<TensorShape> shapes;
     shapes.reserve(inputs.size());
     for (const auto& input : inputs) {
-      OUTCOME_TRY(auto shape, InferInputShape(input));
+      OUTCOME_TRY(auto shape, InferBatchShape(input));
       shapes.push_back(std::move(shape));
     }
     return shapes;
   }
 
-  Result<std::vector<Output> > Forward(const std::vector<Input>& input) {
-    //    auto t0 = std::chrono::high_resolution_clock::now();
-    //
-    auto batch_size = static_cast<int>(input.size());
-
-    std::vector<std::vector<Tensor> > input_samples;
+  Result<vector<vector<Tensor>>> CollectInputTensors(const vector<Input>& inputs) {
+    vector<vector<Tensor>> input_samples;
     input_samples.reserve(inputs_.size());
     for (const auto& t : inputs_) {
       auto name = input_mapping_.at(t.name());
-      std::vector<Tensor> tmp;
-      tmp.reserve(input.size());
-      for (int i = 0; i < input.size(); ++i) {
-        auto& sample = input[i];
+      auto& tmp = input_samples.emplace_back();
+      for (const auto& sample : inputs) {
         if (auto it = sample.find(name); it != sample.end()) {
           tmp.push_back(it->second);
         } else {
-          MMDEPLOY_ERROR("sample {} missing key {}", i, name);
+          MMDEPLOY_ERROR("sample {} missing key {}", &sample - inputs.data(), name);
           return Status(eInvalidArgument);
         }
       }
-      input_samples.push_back(std::move(tmp));
+    }
+    return input_samples;
+  }
+
+  void SaveBatch(vector<vector<Tensor>> samples, vector<int> indices,
+                 vector<vector<vector<Tensor>>>& batch_tensors,
+                 vector<vector<TensorShape>>& batch_shapes,
+                 vector<vector<int>>& batch_sample_idxs) const {
+    if (auto maybe_batch_shape = InferBatchShape(samples)) {
+      batch_shapes.push_back(maybe_batch_shape.value());
+      batch_tensors.push_back(std::move(samples));
+      batch_sample_idxs.push_back(std::move(indices));
+    } else {
+      // cannot assemble batch, do it one by one
+      for (int k = 0; k < indices.size(); ++k) {
+        auto& shapes = batch_shapes.emplace_back();
+        auto& batch = batch_tensors.emplace_back(inputs_.size());
+        batch_sample_idxs.push_back({indices[k]});
+        for (int j = 0; j < inputs_.size(); ++j) {
+          shapes.push_back(samples[j][k].shape());
+          batch[j].push_back(std::move(samples[j][k]));
+        }
+      }
+    }
+  }
+
+  void SamplesToBatches(const vector<vector<Tensor>>& input_samples, size_t n_samples,
+                        vector<vector<vector<Tensor>>>& batch_tensors,
+                        vector<vector<TensorShape>>& batch_shapes,
+                        vector<vector<int>>& batch_sample_idxs) const {
+    // concat all shapes in samples to make comparison easier
+    vector<vector<int64_t>> concat_shapes;
+    concat_shapes.reserve(n_samples);
+    for (size_t i = 0; i < n_samples; ++i) {
+      auto& shape = concat_shapes.emplace_back();
+      for (const auto& input : input_samples) {
+        shape.insert(shape.end(), input[i].shape().begin(), input[i].shape().end());
+      }
+    }
+
+    // cluster samples by concatenated shapes
+    vector<int> shape_idxs(concat_shapes.size());
+    std::iota(shape_idxs.begin(), shape_idxs.end(), 0);
+    std::sort(shape_idxs.begin(), shape_idxs.end(),
+              [&concat_shapes](int i, int j) { return concat_shapes[i] < concat_shapes[j]; });
+    shape_idxs.erase(std::unique(shape_idxs.begin(), shape_idxs.end(),
+                                 [&concat_shapes](int i, int j) {
+                                   return concat_shapes[i] == concat_shapes[j];
+                                 }),
+                     shape_idxs.end());
+
+    // generate batches of samples with equal shapes, limit the batch size by max_batch_size_
+    for (const auto ref_shape_idx : shape_idxs) {
+      const auto& ref_shape = concat_shapes[ref_shape_idx];
+      vector<vector<Tensor>> samples(inputs_.size());
+      vector<int> indices;
+      for (size_t i = 0; i < concat_shapes.size(); ++i) {
+        if (concat_shapes[i] == ref_shape) {
+          for (size_t j = 0; j < inputs_.size(); ++j) {
+            samples[j].push_back(input_samples[j][i]);
+          }
+          indices.push_back(static_cast<int>(i));
+          if (indices.size() == max_batch_size_) {
+            SaveBatch(std::move(samples), std::move(indices), batch_tensors, batch_shapes,
+                      batch_sample_idxs);
+            samples = vector<vector<Tensor>>(inputs_.size());
+            indices = {};
+          }
+        }
+      }
+      if (!indices.empty()) {
+        SaveBatch(std::move(samples), std::move(indices), batch_tensors, batch_shapes,
+                  batch_sample_idxs);
+      }
+    }
+  }
+
+  Result<vector<Output>> Forward(const vector<Input>& inputs) {
+    OUTCOME_TRY(auto input_samples, CollectInputTensors(inputs));
+
+    vector<vector<vector<Tensor>>> batch_tensors;
+    vector<vector<TensorShape>> batch_shapes;
+    vector<vector<int>> batch_sample_indices;
+
+    SamplesToBatches(input_samples, inputs.size(), batch_tensors, batch_shapes,
+                     batch_sample_indices);
+
+    vector<Output> outputs(inputs.size());
+    for (size_t i = 0; i < batch_tensors.size(); ++i) {
+      OUTCOME_TRY(net_->Reshape(batch_shapes[i]));
+      OUTCOME_TRY(CopyInputTensors(batch_tensors[i], batch_shapes[i]));
+      OUTCOME_TRY(net_->Forward());
+      OUTCOME_TRY(CopyOutputTensors(batch_sample_indices[i], outputs));
+      if (i + 1 < batch_tensors.size()) {  // sync if not the last batch
+        OUTCOME_TRY(stream_.Wait());
+      }
     }
 
-    // 1. calculate input shape
-    OUTCOME_TRY(auto input_shapes, InferInputShape(input_samples));
+    if (is_profiling_) {
+      OUTCOME_TRY(stream_.Wait());
+    }
 
-    // 2. call backend's reshape
-    OUTCOME_TRY(net_->Reshape(input_shapes));
+    return outputs;
+  }
 
-    // 3. fill input tensor
+  Result<void> CopyInputTensors(const vector<vector<Tensor>>& batch,
+                                const vector<TensorShape>& shapes) const {
     for (int i = 0; i < inputs_.size(); ++i) {
-      auto& src = input_samples[i];
+      auto& src = batch[i];
       auto& dst = inputs_[i];
-      if (dst.shape() != input_shapes[i]) {
-        MMDEPLOY_ERROR("inconsistent input shape, expect {}, got {}", input_shapes[i], dst.shape());
+      if (dst.shape() != shapes[i]) {
+        MMDEPLOY_ERROR("inconsistent input shape, expect {}, got {}", shapes[i], dst.shape());
         return Status(eFail);
       }
       if (src.size() > 1) {
         for (int j = 0; j < src.size(); ++j) {
-          auto slice = dst.Slice(j);
-          OUTCOME_TRY(src[j].CopyTo(slice, stream_));
+          OUTCOME_TRY(dst.Slice(j).CopyFrom(src[j], stream_));
         }
       } else {
-        OUTCOME_TRY(src[0].CopyTo(dst, stream_));
+        OUTCOME_TRY(src.front().CopyTo(dst, stream_));
       }
     }
+    return success();
+  }
 
-    // 5. forward
-    OUTCOME_TRY(net_->Forward());
-
-    vector<Output> output(batch_size);
-    for (const auto& t : outputs_) {
-      auto name = output_mapping_.at(t.name());
-      auto desc = t.desc();
+  Result<void> CopyOutputTensors(const vector<int>& indices, vector<Output>& outputs) {
+    for (const auto& output : outputs_) {
+      auto name = output_mapping_.at(output.name());
+      auto desc = output.desc();
       desc.device = device_;
       Tensor tmp(desc);
       if (tmp.size()) {
-        OUTCOME_TRY(t.CopyTo(tmp, stream_));
+        OUTCOME_TRY(output.CopyTo(tmp, stream_));
       } else {
         MMDEPLOY_WARN("copy skipped due to zero sized tensor");
       }
-      if (output.size() > 1) {
-        for (int i = 0; i < output.size(); ++i) {
-          output[i].emplace(name, tmp.Slice(i));
+      if (indices.size() > 1) {
+        for (int i = 0; i < indices.size(); ++i) {
+          outputs[indices[i]].emplace(name, tmp.Slice(i));
         }
       } else {
-        output[0].emplace(name, std::move(tmp));
+        outputs[indices.front()].emplace(name, std::move(tmp));
       }
     }
-    if (is_profiling_) {
-      OUTCOME_TRY(stream_.Wait());
-    }
-
-    return output;
+    return success();
   }
 
   Device device_;
@@ -195,6 +287,7 @@ struct NetModule::Impl {
   std::map<std::string, std::string> input_mapping_;
   // outer scope to model output names
   std::map<std::string, std::string> output_mapping_;
+  int max_batch_size_{1};
   bool is_profiling_{false};
 };