Migrate extension/threadpool to new namespace (#5849)

Migrate extension/threadpool to new namespace (#5825)

Summary:
Pull Request resolved: #5825

Migrate these headers under the new ::executorch::extension:: namespace. Add temporary aliases from the old ::torch::executorch namespace so we can migrate users incrementally.

Note that this code incorrectly used `::torch::executorch` instead of `::torch::executor`, so the aliases use the old namespace.

Also, now that we guarantee C++17, we can start using single-line namespace definition syntax.

While I'm here, fix some comments to use Doxygen format, and reword a bit.

Reviewed By: mergennachin

Differential Revision: D63782662

fbshipit-source-id: 673e82269f65a368396929f6c06eb2cdd0903134
(cherry picked from commit 436afce)

Co-authored-by: Dave Bort <[email protected]>

Author: pytorchbot

extension/threadpool/cpuinfo_utils.cpp

@@ -6,17 +6,16 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-#include <executorch/runtime/platform/assert.h>
+#include <executorch/extension/threadpool/cpuinfo_utils.h>
+
 #include <fstream>
 #include <mutex>
 #include <string>
 #include <vector>
 
-#include "cpuinfo_utils.h"
+#include <executorch/runtime/platform/assert.h>
 
-namespace torch {
-namespace executorch {
-namespace cpuinfo {
+namespace executorch::extension::cpuinfo {
 
 // Ignore revisions (last digit (4 LSBs))
 #define CPUINFO_ARM_MIDR_CORTEX_A520 UINT32_C(0x410FD800)
@@ -171,6 +170,4 @@ uint32_t get_num_performant_cores() {
   }
 }
 
-} // namespace cpuinfo
-} // namespace executorch
-} // namespace torch
+} // namespace executorch::extension::cpuinfo

extension/threadpool/cpuinfo_utils.h

@@ -10,12 +10,15 @@
 
 #include <cpuinfo.h>
 
-namespace torch {
-namespace executorch {
-namespace cpuinfo {
+namespace executorch::extension::cpuinfo {
 
 uint32_t get_num_performant_cores();
 
-} // namespace cpuinfo
-} // namespace executorch
-} // namespace torch
+} // namespace executorch::extension::cpuinfo
+
+namespace torch::executorch::cpuinfo { // DEPRECATED
+// TODO(T197294990): Remove these deprecated aliases once all users have moved
+// to the new `::executorch` namespaces. Note that threadpool incorrectly used
+// the namespace `torch::executorch` instead of `torch::executor`.
+using ::executorch::extension::cpuinfo::get_num_performant_cores; // DEPRECATED
+} // namespace torch::executorch::cpuinfo

extension/threadpool/test/threadpool_test.cpp

@@ -6,14 +6,16 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-#include <gtest/gtest.h>
+#include <executorch/extension/threadpool/threadpool.h>
+
 #include <mutex>
 #include <numeric>
 #include <random>
 
-#include <executorch/extension/threadpool/threadpool.h>
 #include <executorch/extension/threadpool/threadpool_guard.h>
 
+#include <gtest/gtest.h>
+
 using namespace ::testing;
 
 namespace {
@@ -63,7 +65,7 @@ void run_lambda_with_size(
     size_t grain_size) {
   size_t num_grains = div_round_up(range, grain_size);
 
-  auto threadpool = torch::executorch::threadpool::get_threadpool();
+  auto threadpool = ::executorch::extension::threadpool::get_threadpool();
   threadpool->run(f, range);
 }
 } // namespace
@@ -82,7 +84,7 @@ TEST(ThreadPoolTest, ParallelAdd) {
     }
   };
 
-  auto threadpool = torch::executorch::threadpool::get_threadpool();
+  auto threadpool = ::executorch::extension::threadpool::get_threadpool();
   EXPECT_GT(threadpool->get_thread_count(), 1);
 
   generate_add_test_inputs(a, b, c_ref, c, vector_size);
@@ -125,7 +127,7 @@ TEST(ThreadPoolTest, ParallelReduce) {
     }
   };
 
-  auto threadpool = torch::executorch::threadpool::get_threadpool();
+  auto threadpool = ::executorch::extension::threadpool::get_threadpool();
   EXPECT_GT(threadpool->get_thread_count(), 1);
 
   generate_reduce_test_inputs(a, c_ref, vector_size);
@@ -142,46 +144,50 @@ TEST(ThreadPoolTest, ParallelReduce) {
 // Copied from
 // caffe2/aten/src/ATen/test/test_thread_pool_guard.cp
 TEST(TestNoThreadPoolGuard, TestThreadPoolGuard) {
-  auto threadpool_ptr = torch::executorch::threadpool::get_pthreadpool();
+  auto threadpool_ptr = ::executorch::extension::threadpool::get_pthreadpool();
 
   ASSERT_NE(threadpool_ptr, nullptr);
   {
-    torch::executorch::threadpool::NoThreadPoolGuard g1;
-    auto threadpool_ptr1 = torch::executorch::threadpool::get_pthreadpool();
+    ::executorch::extension::threadpool::NoThreadPoolGuard g1;
+    auto threadpool_ptr1 =
+        ::executorch::extension::threadpool::get_pthreadpool();
     ASSERT_EQ(threadpool_ptr1, nullptr);
 
     {
-      torch::executorch::threadpool::NoThreadPoolGuard g2;
-      auto threadpool_ptr2 = torch::executorch::threadpool::get_pthreadpool();
+      ::executorch::extension::threadpool::NoThreadPoolGuard g2;
+      auto threadpool_ptr2 =
+          ::executorch::extension::threadpool::get_pthreadpool();
       ASSERT_EQ(threadpool_ptr2, nullptr);
     }
 
     // Guard should restore prev value (nullptr)
-    auto threadpool_ptr3 = torch::executorch::threadpool::get_pthreadpool();
+    auto threadpool_ptr3 =
+        ::executorch::extension::threadpool::get_pthreadpool();
     ASSERT_EQ(threadpool_ptr3, nullptr);
   }
 
   // Guard should restore prev value (pthreadpool_)
-  auto threadpool_ptr4 = torch::executorch::threadpool::get_pthreadpool();
+  auto threadpool_ptr4 = ::executorch::extension::threadpool::get_pthreadpool();
   ASSERT_NE(threadpool_ptr4, nullptr);
   ASSERT_EQ(threadpool_ptr4, threadpool_ptr);
 }
 
 TEST(TestNoThreadPoolGuard, TestRunWithGuard) {
   const std::vector<int64_t> array = {1, 2, 3};
 
-  auto pool = torch::executorch::threadpool::get_threadpool();
+  auto pool = ::executorch::extension::threadpool::get_threadpool();
   int64_t inner = 0;
   {
     // Run on same thread
-    torch::executorch::threadpool::NoThreadPoolGuard g1;
+    ::executorch::extension::threadpool::NoThreadPoolGuard g1;
     auto fn = [&array, &inner](const size_t task_id) {
       inner += array[task_id];
     };
     pool->run(fn, 3);
 
     // confirm the guard is on
-    auto threadpool_ptr = torch::executorch::threadpool::get_pthreadpool();
+    auto threadpool_ptr =
+        ::executorch::extension::threadpool::get_pthreadpool();
     ASSERT_EQ(threadpool_ptr, nullptr);
   }
   ASSERT_EQ(inner, 6);

extension/threadpool/threadpool.cpp

@@ -7,18 +7,17 @@
  */
 
 #include <executorch/extension/threadpool/threadpool.h>
+
+#include <algorithm>
+#include <atomic>
+#include <memory>
+
 #include <executorch/extension/threadpool/threadpool_guard.h>
 #include <executorch/runtime/platform/assert.h>
-#include <algorithm>
 
 #include <cpuinfo.h>
 
-#include <atomic>
-#include <memory>
-
-namespace torch {
-namespace executorch {
-namespace threadpool {
+namespace executorch::extension::threadpool {
 
 #if !(defined(WIN32))
 namespace {
@@ -138,6 +137,4 @@ pthreadpool_t get_pthreadpool() {
   return threadpool->threadpool_.get();
 }
 
-} // namespace threadpool
-} // namespace executorch
-} // namespace torch
+} // namespace executorch::extension::threadpool

extension/threadpool/threadpool.h

@@ -1,17 +1,20 @@
-#pragma once
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
 
-#include <pthreadpool.h>
+#pragma once
 
-// @nolint PATTERNLINT Ok to use stdlib for this optional library
 #include <functional>
-// @nolint PATTERNLINT Ok to use stdlib for this optional library
 #include <memory>
-// @nolint PATTERNLINT Ok to use stdlib for this optional library
 #include <mutex>
 
-namespace torch {
-namespace executorch {
-namespace threadpool {
+#include <pthreadpool.h>
+
+namespace executorch::extension::threadpool {
 
 class ThreadPool final {
  public:
@@ -26,55 +29,64 @@ class ThreadPool final {
   ThreadPool& operator=(const ThreadPool&) = delete;
 
   // Make threadpool non-movable.
-  // For now this is non-movable, but if we want to have clients
-  // such as say torch::executorch::Executor, to be able to own
-  // threadpool, then we will have to make this movable.
   ThreadPool(ThreadPool&&) = delete;
   ThreadPool& operator=(ThreadPool&&) = delete;
 
   size_t get_thread_count() const;
 
-  /*
-   * Resets the threadpool by creating a new threadpool with requested # of
-   * threads. This is not a thread safe call. When calling this method, threads
-   * of the threadpool might be doing some work. Some other code may also be
-   * holding on to the threadpool pointer, that is no longer valid. This is a
-   * private API, which will later be replaced by something that allows creating
-   * of threadpool with requested size and use such a threadpool with backend
-   * delegates, custom ops or optimized lib.
+  /**
+   * INTERNAL: Resets the threadpool by creating a new threadpool with requested
+   * # of threads. This is not a thread safe call. When calling this method,
+   * threads of the threadpool might be doing some work. Some other code may
+   * also be holding on to the threadpool pointer, that is no longer valid. This
+   * is a private API, which will later be replaced by something that allows
+   * creating of threadpool with requested size and use such a threadpool with
+   * backend delegates, custom ops or optimized lib.
    */
+  [[deprecated("This API is experimental and may change without notice.")]]
   bool _unsafe_reset_threadpool(uint32_t num_threads);
 
-  // Run, in parallel, function fn(task_id) over task_id in range [0, range).
-  // This function is blocking.  All input is processed by the time it returns.
-  // NoThreadPoolGuard (see threadpool_guard.h) can used to disable
-  // use of multiple threads with the scope of the guard
-  // When NoThreadPoolGuard is not used all calls to run method are serialized.
+  /**
+   * Run, in parallel, function fn(task_id) over task_id in range [0, range).
+   * This function is blocking.  All input is processed by the time it returns.
+   * NoThreadPoolGuard (see threadpool_guard.h) can used to disable use of
+   * multiple threads with the scope of the guard When NoThreadPoolGuard is not
+   * used all calls to run method are serialized.
+   */
   void run(const std::function<void(size_t)>& fn, size_t range);
 
  private:
   friend pthreadpool_t get_pthreadpool();
 
  private:
-  // This mutex is used inside get_thread_count API but it is not
-  // really needed. Since data members of ThreadPool objects are not
-  // really mutable.
-  // Figure out if we will allow set_num_threads API, in which mutex
-  // will be useful. Otherwise remove it.
-  // TODO(kimishpatel)
+  // This mutex is used inside get_thread_count API but it is not really needed
+  // since data members of ThreadPool objects are not really mutable.
+  // TODO(kimishpatel): Figure out if we will allow set_num_threads API, in
+  // which case this mutex will be useful. Otherwise remove it.
   mutable std::mutex mutex_;
   std::unique_ptr<pthreadpool, decltype(&pthreadpool_destroy)> threadpool_;
 };
 
-// Return a singleton instance of ThreadPool for ATen/TH multithreading.
+/**
+ * Returns the singleton instance of ThreadPool for ATen/TH multithreading.
+ */
 ThreadPool* get_threadpool();
 
-// Exposes the underlying implementation of ThreadPool.
-// Only for use in external libraries so as to unify threading across
-// internal (i.e. ATen, etc.) and external (e.g. NNPACK, QNNPACK, XNNPACK)
-// use cases.
+/**
+ * Returns the underlying pthreadpool instance used by the implementation of
+ * ThreadPool returned by `get_threadpool()`. Only for use in external libraries
+ * so as to unify threading across internal (i.e. ATen, etc.) and external (e.g.
+ * NNPACK, QNNPACK, XNNPACK) use cases.
+ */
 pthreadpool_t get_pthreadpool();
 
-} // namespace threadpool
-} // namespace executorch
-} // namespace torch
+} // namespace executorch::extension::threadpool
+
+namespace torch::executorch::threadpool { // DEPRECATED
+// TODO(T197294990): Remove these deprecated aliases once all users have moved
+// to the new `::executorch` namespaces. Note that threadpool incorrectly used
+// the namespace `torch::executorch` instead of `torch::executor`.
+using ::executorch::extension::threadpool::get_pthreadpool; // DEPRECATED
+using ::executorch::extension::threadpool::get_threadpool; // DEPRECATED
+using ::executorch::extension::threadpool::ThreadPool; // DEPRECATED
+} // namespace torch::executorch::threadpool

extension/threadpool/threadpool_guard.cpp

@@ -8,9 +8,7 @@
 
 #include <executorch/extension/threadpool/threadpool_guard.h>
 
-namespace torch {
-namespace executorch {
-namespace threadpool {
+namespace executorch::extension::threadpool {
 
 thread_local bool NoThreadPoolGuard_enabled = false;
 
@@ -22,6 +20,4 @@ void NoThreadPoolGuard::set_enabled(bool enabled) {
   NoThreadPoolGuard_enabled = enabled;
 }
 
-} // namespace threadpool
-} // namespace executorch
-} // namespace torch
+} // namespace executorch::extension::threadpool

extension/threadpool/threadpool_guard.h

@@ -8,9 +8,7 @@
 
 #pragma once
 
-namespace torch {
-namespace executorch {
-namespace threadpool {
+namespace executorch::extension::threadpool {
 
 // A RAII, thread local (!) guard that enables or disables guard upon
 // construction, and sets it back to the original value upon destruction.
@@ -29,6 +27,11 @@ struct NoThreadPoolGuard {
   const bool prev_mode_;
 };
 
-} // namespace threadpool
-} // namespace executorch
-} // namespace torch
+} // namespace executorch::extension::threadpool
+
+namespace torch::executorch::threadpool { // DEPRECATED
+// TODO(T197294990): Remove these deprecated aliases once all users have moved
+// to the new `::executorch` namespaces. Note that threadpool incorrectly used
+// the namespace `torch::executorch` instead of `torch::executor`.
+using ::executorch::extension::threadpool::NoThreadPoolGuard; // DEPRECATED
+} // namespace torch::executorch::threadpool