Add a simple threadpool.

Author: kingcrimsontianyu

cpp/benchmarks/CMakeLists.txt

@@ -44,6 +44,10 @@ function(kvikio_add_benchmark)
   add_executable(${_KVIKIO_NAME} ${_KVIKIO_SOURCES})
   set_target_properties(${_KVIKIO_NAME} PROPERTIES INSTALL_RPATH "\$ORIGIN/../../../lib")
 
+<<<<<<< HEAD
+=======
+  target_include_directories(${_KVIKIO_NAME} PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}")
+>>>>>>> e54d507 (Add a simple threadpool.)
   target_link_libraries(${_KVIKIO_NAME} PUBLIC benchmark::benchmark kvikio::kvikio)
 
   if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
@@ -59,4 +63,10 @@ function(kvikio_add_benchmark)
   )
 endfunction()
 
+<<<<<<< HEAD
 kvikio_add_benchmark(NAME THREADPOOL_BENCHMARK SOURCES "threadpool/threadpool_benchmark.cpp")
+=======
+kvikio_add_benchmark(
+  NAME THREADPOOL_BENCHMARK SOURCES "threadpool/threadpool_benchmark.cpp" "utils/utils.cpp"
+)
+>>>>>>> e54d507 (Add a simple threadpool.)

cpp/benchmarks/threadpool/threadpool_benchmark.cpp

@@ -28,6 +28,7 @@
 
 #include <benchmark/benchmark.h>
 #include <kvikio/defaults.hpp>
+#include <utils/utils.hpp>
 
 namespace kvikio {
 enum class ScalingType : uint8_t {
@@ -88,6 +89,8 @@ int main(int argc, char** argv)
     ->Unit(benchmark::kMillisecond)
     ->MinTime(2);
 
+  kvikio::utils::explain_default_metrics();
+
   benchmark::RunSpecifiedBenchmarks();
   benchmark::Shutdown();
 }

cpp/benchmarks/utils/utils.cpp

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2025, NVIDIA CORPORATION.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <benchmark/benchmark.h>
+#include <utils/utils.hpp>
+
+namespace kvikio::utils {
+void explain_default_metrics()
+{
+  benchmark::AddCustomContext(
+    "Time",
+    "The average real time (i.e. wall-clock time) of the entire process per benchmark iteration.");
+  benchmark::AddCustomContext(
+    "CPU",
+    "The average CPU time of the main thread per benchmark iteration. The timer is accumulated "
+    "only when the main thread is being executed.");
+}
+}  // namespace kvikio::utils

cpp/benchmarks/utils/utils.hpp

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2025, NVIDIA CORPORATION.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+namespace kvikio::utils {
+void explain_default_metrics();
+}

cpp/include/kvikio/threadpool_simple.hpp

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2025, NVIDIA CORPORATION.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions andc
+ * limitations under the License.
+ */
+
+#include <atomic>
+#include <functional>
+#include <future>
+#include <thread>
+#include <type_traits>
+#include <vector>
+
+namespace kvikio {
+/**
+ * @brief A simple thread pool that executes tasks in an embarrassingly parallel manner.
+ *
+ * The implementation is header-only.
+ */
+class ThreadPoolSimple {
+ public:
+  ThreadPoolSimple(
+    unsigned int num_threads, const std::function<void()>& worker_thread_init_func = [] {})
+    : _num_threads{num_threads}, _worker_thread_init_func{worker_thread_init_func}
+  {
+  }
+
+  void reset();
+
+  template <typename F, typename R = std::invoke_result_t<std::decay_t<F>>>
+  [[nodiscard]] std::future<R> submit_task(F&& task)
+  {
+  }
+
+ private:
+  void worker() {}
+
+  void create_threads()
+  {
+    for (unsigned int i = 0; i < _num_threads; ++i) {
+      _thread_container.emplace_back(&ThreadPoolSimple::worker, _worker_thread_init_func);
+    }
+  }
+
+  void destroy_threads() {}
+
+  std::atomic_bool _done{false};
+  unsigned int _num_threads{};
+  std::function<void()> _worker_thread_init_func{};
+  std::vector<std::thread> _thread_container{};
+};
+
+}  // namespace kvikio