Made thread pool itself thread safe. Besides, added some extra safety for StreamMgr singleton instance allocation.

src/lasp/device/lasp_streammgr.cpp

@@ -9,6 +9,7 @@
 #include <functional>
 #include <iostream>
 #include <memory>
+#include <mutex>
 
 using std::cerr;
 using std::endl;
@@ -21,8 +22,9 @@ using rte = std::runtime_error;
  * to it has been destroyed (no global stuff left).
  */
 std::weak_ptr<StreamMgr> _mgr;
+std::mutex _mgr_mutex;
 
-
+using Lck = std::scoped_lock<std::mutex>;
 
 /**
  * @brief The only way to obtain a stream manager, can only be called from the
@@ -35,6 +37,14 @@ SmgrHandle StreamMgr::getInstance() {
 
   auto mgr = _mgr.lock();
   if (!mgr) {
+    // Double Check Locking Pattern, if two threads would simultaneously
+    // instantiate the singleton instance.
+    Lck lck(_mgr_mutex);
+
+    auto mgr = _mgr.lock();
+    if (mgr) {
+      return mgr;
+    }
 
     mgr = SmgrHandle(new StreamMgr());
     if (!mgr) {
@@ -70,7 +80,6 @@ void StreamMgr::checkRightThread() const {
 void StreamMgr::rescanDAQDevices(bool background,
                                  std::function<void()> callback) {
   DEBUGTRACE_ENTER;
-  auto &pool = getPool();
 
   checkRightThread();
   if (_inputStream || _outputStream) {
@@ -87,7 +96,7 @@ void StreamMgr::rescanDAQDevices(bool background,
     rescanDAQDevices_impl(callback);
   } else {
     DEBUGTRACE_PRINT("Rescanning DAQ devices on different thread...");
-    pool.push_task(&StreamMgr::rescanDAQDevices_impl, this, callback);
+    _pool.push_task(&StreamMgr::rescanDAQDevices_impl, this, callback);
   }
 }
 void StreamMgr::rescanDAQDevices_impl(std::function<void()> callback) {

src/lasp/device/lasp_streammgr.h

@@ -1,6 +1,7 @@
 #pragma once
 #include "lasp_daq.h"
 #include "lasp_siggen.h"
+#include "lasp_thread.h"
 #include <list>
 #include <memory>
 #include <mutex>
@@ -30,6 +31,8 @@ class StreamMgr {
    */
   std::unique_ptr<Daq> _inputStream, _outputStream;
 
+  ThreadSafeThreadPool _pool;
+
   /**
    * @brief All indata handlers are called when input data is available. Note
    * that they can be called from different threads and should take care of

src/lasp/dsp/lasp_biquadbank.cpp

@@ -51,7 +51,9 @@ SeriesBiquad SeriesBiquad::firstOrderHighPass(const d fs, const d cuton_Hz) {
     throw rte("Invalid cuton frequency: " + std::to_string(cuton_Hz) + " [Hz]");
   }
   if (cuton_Hz >= 0.98 * fs / 2) {
-    throw rte("Invalid cuton frequency. We limit this to 0.98* fs / 2. Given value" + std::to_string(cuton_Hz) + " [Hz]");
+    throw rte(
+        "Invalid cuton frequency. We limit this to 0.98* fs / 2. Given value" +
+        std::to_string(cuton_Hz) + " [Hz]");
   }
 
   const d tau = 1 / (2 * arma::datum::pi * cuton_Hz);
@@ -76,10 +78,8 @@ SeriesBiquad SeriesBiquad::firstOrderHighPass(const d fs, const d cuton_Hz) {
   coefs(5) = 0;
 
   return SeriesBiquad(coefs);
-
 }
 
-
 std::unique_ptr<Filter> SeriesBiquad::clone() const {
   // sos.as_col() concatenates all columns, exactly what we want.
   return std::make_unique<SeriesBiquad>(sos.as_col());
@@ -124,7 +124,6 @@ BiquadBank::BiquadBank(const dmat &filters, const vd *gains) {
    * for use.
    */
   lock lck(_mtx);
-  getPool();
 
   for (us i = 0; i < filters.n_cols; i++) {
     _filters.emplace_back(filters.col(i));
@@ -153,10 +152,9 @@ void BiquadBank::filter(vd &inout) {
   std::vector<std::future<vd>> futs;
 
 #if 1
-  auto &pool = getPool();
   vd inout_cpy = inout;
   for (us i = 0; i < _filters.size(); i++) {
-    futs.emplace_back(pool.submit(
+    futs.emplace_back(_pool.submit(
         [&](vd inout, us i) {
           _filters[i].filter(inout);
           return inout;

src/lasp/dsp/lasp_biquadbank.h

@@ -1,5 +1,6 @@
 #pragma once
 #include "lasp_filter.h"
+#include "lasp_thread.h"
 
 /**
  * \addtogroup dsp
@@ -60,6 +61,7 @@ public:
 class BiquadBank : public Filter {
   std::vector<SeriesBiquad> _filters;
   vd _gains;
+  ThreadSafeThreadPool _pool;
   mutable std::mutex _mtx;
 
 public:

src/lasp/dsp/lasp_slm.cpp

@@ -37,9 +37,6 @@ SLM::SLM(const d fs, const d Lref, const us downsampling_fac, const d tau,
   DEBUGTRACE_ENTER;
   DEBUGTRACE_PRINT(_alpha);
 
-  // Make sure thread pool is running
-  getPool();
-
   if (Lref <= 0) {
     throw rte("Invalid reference level");
   }

src/lasp/dsp/lasp_slm.h

@@ -1,6 +1,7 @@
 #pragma once
 #include "lasp_biquadbank.h"
 #include "lasp_filter.h"
+#include "lasp_thread.h"
 #include <memory>
 #include <optional>
 
@@ -14,6 +15,7 @@
  * channel. A channel is the result  of a filtered signal
  */
 class SLM {
+  ThreadSafeThreadPool _pool;
   /**
    * @brief A, C or Z weighting, depending on the pre-filter installed.
    */

src/lasp/dsp/lasp_thread.cpp

@@ -5,21 +5,31 @@
 #include <memory>
 
 /**
- * @brief It seems to work much better in cooperation with Pybind11 when this
- * singleton is implemented with a unique_ptr.
+ * @brief Store a global weak_ptr, that is used to create new shared pointers
+ * if any other shared pointers are still alive. If not, we create a new
+ * instance.
  */
-std::unique_ptr<BS::thread_pool> _static_storage_threadpool;
+std::weak_ptr<BS::thread_pool> _global_weak_pool;
 
-void destroyThreadPool() {
+/**
+ * @brief Static storage for the mutex.
+ */
+std::mutex ThreadSafeThreadPool::_mtx;
+
+using Lck = std::scoped_lock<std::mutex>;
+using rte = std::runtime_error;
+
+ThreadSafeThreadPool::ThreadSafeThreadPool() {
   DEBUGTRACE_ENTER;
-  _static_storage_threadpool = nullptr;
+  Lck lck(_mtx);
+  /// See if we can get it from the global ptr. If not, time to allocate it.
+  _pool = _global_weak_pool.lock();
+  if (!_pool) {
+    _pool = std::make_shared<BS::thread_pool>();
+    if (!_pool) {
+      throw rte("Fatal: could not allocate thread pool!");
     }
-
-BS::thread_pool &getPool() {
-  /* DEBUGTRACE_ENTER; */
-  if (!_static_storage_threadpool) {
-    DEBUGTRACE_PRINT("Creating new thread pool");
-    _static_storage_threadpool = std::make_unique<BS::thread_pool>();
+    // Update global weak pointer
+    _global_weak_pool = _pool;
   }
-  return *_static_storage_threadpool;
 }

src/lasp/dsp/lasp_thread.h

@@ -2,18 +2,54 @@
 #include "BS_thread_pool.hpp"
 
 /**
- * @brief Return reference to global (singleton) thread pool. The threadpool is
- * created using the default argument, which results in exactly
- * hardware_concurrency() amount of threads.
- *
- * @return Thread pool ref.
+ * @brief Simple wrapper around BS::thread_pool that makes a BS::thread_pool a
+ * singleton, such that a thread pool can be used around in the code, and
+ * safely spawn threads also from other threads. Only wraps a submit() and
+ * push_task for now.
  */
-BS::thread_pool& getPool();
+class ThreadSafeThreadPool {
+
+  /**
+   * @brief Shared access to the thread pool.
+   */
+  std::shared_ptr<BS::thread_pool> _pool;
+  /**
+   * @brief Global mutex, used to restrict pool access to a single thread at
+   * once.
+   */
+  static std::mutex _mtx;
+
+  using Lck = std::scoped_lock<std::mutex>;
+  ThreadSafeThreadPool(const ThreadSafeThreadPool&) = delete;
+  ThreadSafeThreadPool &
+  operator=(const ThreadSafeThreadPool&) = delete;
+
+public:
+  /**
+   * @brief Instantiate handle to the thread pool.
+   */
+  ThreadSafeThreadPool();
 
   
   /**
- * @brief The global thread pool is stored in a unique_ptr, so in normal C++
- * code the thread pool is deleted at the end of main(). However this does not
- * hold when LASP code is run
+   * @brief Wrapper around BS::thread_pool::submit(...)
    */
-void destroyThreadPool();
+  template <
+      typename F, typename... A,
+      typename R = std::invoke_result_t<std::decay_t<F>, std::decay_t<A>...>>
+  [[nodiscard]] std::future<R> submit(F &&task, A &&...args) {
+    /// Lock access to pool
+    Lck lck(_mtx);
+
+    return _pool->submit(task, args...);
+  }
+  /**
+   * @brief Wrapper around BS::thread_pool::push_task(...)
+   */
+  template <typename F, typename... A> void push_task(F &&task, A &&...args) {
+    /// Lock access to pool
+    Lck lck(_mtx);
+    _pool->push_task(task, args...);
+  }
+};
+

src/lasp/dsp/lasp_threadedindatahandler.cpp

@@ -62,8 +62,6 @@ ThreadedInDataHandlerBase::ThreadedInDataHandlerBase(SmgrHandle mgr,
 
   DEBUGTRACE_ENTER;
 
-  // Initialize thread pool, if not already done
-  getPool();
 }
 void ThreadedInDataHandlerBase::startThread() {
   DEBUGTRACE_ENTER;
@@ -82,10 +80,9 @@ void ThreadedInDataHandlerBase::_inCallbackFromInDataHandler(
 
   _queue->push(daqdata);
   if (!_thread_running) {
-    auto &pool = getPool();
     DEBUGTRACE_PRINT("Pushing new thread in pool");
     _thread_running = true;
-    pool.push_task(&ThreadedInDataHandlerBase::threadFcn, this);
+    _pool.push_task(&ThreadedInDataHandlerBase::threadFcn, this);
   }
 }
 

src/lasp/dsp/lasp_threadedindatahandler.h

@@ -1,6 +1,7 @@
 #pragma once
 #include "debugtrace.hpp"
 #include "lasp_indatahandler.h"
+#include "lasp_thread.h"
 #include <atomic>
 #include <memory>
 #include <mutex>
@@ -36,6 +37,8 @@ class ThreadedInDataHandlerBase {
   std::atomic<bool> _thread_running{false};
   std::atomic<bool> _thread_can_safely_run{false};
 
+  ThreadSafeThreadPool _pool;
+
   /**
    * @brief Function pointer that is called when new DaqData arrives.
    */

third_party/gsl-lite

@@ -1 +1 @@
-Subproject commit 4720a2980a30da085b4ddb4a0ea2a71af7351a48
+Subproject commit a8c7e5bbbd08841836f9b92d72747fb8769dbec4