Fetch and use BS thread_pool (#408)

Instead of hard coding the header of [`BS::thread_pool`](https://github.com/bshoshany/thread-pool?tab=readme-ov-file), we now fetch the implementation. Done for cudf in rapidsai/cudf#16210.

Authors:
  - Mads R. B. Kristensen (https://github.com/madsbk)
  - Kyle Edwards (https://github.com/KyleFromNVIDIA)

Approvers:
  - Bradley Dice (https://github.com/bdice)

URL: #408

cpp/CMakeLists.txt

@@ -81,6 +81,7 @@ else()
 endif()
 
 include(cmake/thirdparty/get_nvtx.cmake)
+include(cmake/thirdparty/get_thread_pool.cmake)
 
 # library targets
 add_library(kvikio INTERFACE)
@@ -127,8 +128,9 @@ target_include_directories(
   kvikio INTERFACE "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>"
                    "$<INSTALL_INTERFACE:include>"
 )
-
-target_link_libraries(kvikio INTERFACE Threads::Threads ${CMAKE_DL_LIBS} nvtx3::nvtx3-cpp)
+target_link_libraries(
+  kvikio INTERFACE Threads::Threads ${CMAKE_DL_LIBS} nvtx3::nvtx3-cpp BS::thread_pool
+)
 target_compile_features(kvikio INTERFACE cxx_std_17)
 
 # optionally build examples

cpp/cmake/thirdparty/get_thread_pool.cmake

@@ -0,0 +1,25 @@
+# =============================================================================
+# Copyright (c) 2024, 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.
+# =============================================================================
+
+# Need to call rapids_cpm_bs_thread_pool to get support for an installed version of thread-pool and
+# to support installing it ourselves
+function(find_and_configure_thread_pool)
+  include(${rapids-cmake-dir}/cpm/bs_thread_pool.cmake)
+
+  # Find or install thread-pool
+  rapids_cpm_bs_thread_pool(BUILD_EXPORT_SET kvikio-exports INSTALL_EXPORT_SET kvikio-exports)
+
+endfunction()
+
+find_and_configure_thread_pool()

cpp/include/kvikio/defaults.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022-2023, NVIDIA CORPORATION.
+ * Copyright (c) 2022-2024, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,8 +23,9 @@
 #include <string>
 #include <utility>
 
+#include <BS_thread_pool.hpp>
+
 #include <kvikio/shim/cufile.hpp>
-#include <kvikio/thread_pool.hpp>
 
 namespace kvikio {
 namespace detail {
@@ -78,7 +79,7 @@ inline bool getenv_or(std::string_view env_var_name, bool default_val)
  */
 class defaults {
  private:
-  kvikio::third_party::thread_pool _thread_pool{get_num_threads_from_env()};
+  BS::thread_pool _thread_pool{get_num_threads_from_env()};
   bool _compat_mode;
   std::size_t _task_size;
   std::size_t _gds_threshold;
@@ -166,10 +167,7 @@ class defaults {
    *
    * @return The the default thread pool instance.
    */
-  [[nodiscard]] static kvikio::third_party::thread_pool& thread_pool()
-  {
-    return instance()->_thread_pool;
-  }
+  [[nodiscard]] static BS::thread_pool& thread_pool() { return instance()->_thread_pool; }
 
   /**
    * @brief Get the number of threads in the default thread pool.

cpp/include/kvikio/parallel_operation.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2022, NVIDIA CORPORATION.
+ * Copyright (c) 2021-2024, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -28,6 +28,18 @@
 
 namespace kvikio {
 
+namespace detail {
+
+template <typename F, typename T>
+std::future<std::size_t> submit_task(
+  F op, T buf, std::size_t size, std::size_t file_offset, std::size_t devPtr_offset)
+{
+  return defaults::thread_pool().submit_task(
+    [=] { return op(buf, size, file_offset, devPtr_offset); });
+}
+
+}  // namespace detail
+
 /**
  * @brief Apply read or write operation in parallel.
  *
@@ -52,7 +64,7 @@ std::future<std::size_t> parallel_io(F op,
 
   // Single-task guard
   if (task_size >= size || page_size >= size) {
-    return defaults::thread_pool().submit(op, buf, size, file_offset, devPtr_offset);
+    return detail::submit_task(op, buf, size, file_offset, devPtr_offset);
   }
 
   // We know an upper bound of the total number of tasks
@@ -61,16 +73,14 @@ std::future<std::size_t> parallel_io(F op,
 
   // 1) Submit `task_size` sized tasks
   while (size >= task_size) {
-    tasks.push_back(defaults::thread_pool().submit(op, buf, task_size, file_offset, devPtr_offset));
+    tasks.push_back(detail::submit_task(op, buf, task_size, file_offset, devPtr_offset));
     file_offset += task_size;
     devPtr_offset += task_size;
     size -= task_size;
   }
 
   // 2) Submit a task for the remainder
-  if (size > 0) {
-    tasks.push_back(defaults::thread_pool().submit(op, buf, size, file_offset, devPtr_offset));
-  }
+  if (size > 0) { tasks.push_back(detail::submit_task(op, buf, size, file_offset, devPtr_offset)); }
 
   // Finally, we sum the result of all tasks.
   auto gather_tasks = [](std::vector<std::future<std::size_t>>&& tasks) -> std::size_t {