Add local thread pool to CCheckQueue

src/checkqueue.h

@@ -6,6 +6,8 @@
 #define BITCOIN_CHECKQUEUE_H
 
 #include <sync.h>
+#include <tinyformat.h>
+#include <util/threadnames.h>
 
 #include <algorithm>
 #include <vector>
@@ -62,8 +64,11 @@ private:
     //! The maximum number of elements to be processed in one batch
     const unsigned int nBatchSize;
 
+    std::vector<std::thread> m_worker_threads;
+    bool m_request_stop{false};
+
     /** Internal function that does bulk of the verification work. */
-    bool Loop(bool fMaster = false)
+    bool Loop(bool fMaster)
     {
         boost::condition_variable& cond = fMaster ? condMaster : condWorker;
         std::vector<T> vChecks;
@@ -85,7 +90,7 @@ private:
                     nTotal++;
                 }
                 // logically, the do loop starts here
-                while (queue.empty()) {
+                while (queue.empty() && !m_request_stop) {
                     if (fMaster && nTodo == 0) {
                         nTotal--;
                         bool fRet = fAllOk;
@@ -98,6 +103,10 @@ private:
                     cond.wait(lock); // wait
                     nIdle--;
                 }
+                if (m_request_stop) {
+                    return false;
+                }
+
                 // Decide how many work units to process now.
                 // * Do not try to do everything at once, but aim for increasingly smaller batches so
                 //   all workers finish approximately simultaneously.
@@ -132,16 +141,34 @@ public:
     {
     }
 
+    //! Create a pool of new worker threads.
+    void StartWorkerThreads(const int threads_num)
+    {
+        {
+            boost::unique_lock<boost::mutex> lock(mutex);
+            nIdle = 0;
+            nTotal = 0;
+            fAllOk = true;
+        }
+        assert(m_worker_threads.empty());
+        for (int n = 0; n < threads_num; ++n) {
+            m_worker_threads.emplace_back([this, n]() {
+                util::ThreadRename(strprintf("scriptch.%i", n));
+                Loop(false /* worker thread */);
+            });
+        }
+    }
+
     //! Worker thread
     void Thread()
     {
-        Loop();
+        Loop(false /* worker thread */);
     }
 
     //! Wait until execution finishes, and return whether all evaluations were successful.
     bool Wait()
     {
-        return Loop(true);
+        return Loop(true /* master thread */);
     }
 
     //! Add a batch of checks to the queue
@@ -159,8 +186,25 @@ public:
             condWorker.notify_all();
     }
 
+    //! Stop all of the worker threads.
+    void StopWorkerThreads()
+    {
+        {
+            boost::unique_lock<boost::mutex> lock(mutex);
+            m_request_stop = true;
+        }
+        condWorker.notify_all();
+        for (std::thread& t : m_worker_threads) {
+            t.join();
+        }
+        m_worker_threads.clear();
+        boost::unique_lock<boost::mutex> lock(mutex);
+        m_request_stop = false;
+    }
+
     ~CCheckQueue()
     {
+        assert(m_worker_threads.empty());
     }
 
 };