Make semaphore count configurable and default to 32.

Author: jcoupey

src/structures/typedefs.h

@@ -82,6 +82,7 @@ constexpr unsigned MAX_EXPLORATION_LEVEL = 5;
 
 constexpr unsigned DEFAULT_EXPLORATION_LEVEL = 5;
 constexpr unsigned DEFAULT_THREADS_NUMBER = 4;
+constexpr unsigned MAX_ROUTING_THREADS = 32;
 
 constexpr auto DEFAULT_MAX_TASKS = std::numeric_limits<size_t>::max();
 constexpr auto DEFAULT_MAX_TRAVEL_TIME = std::numeric_limits<Duration>::max();

src/structures/vroom/input/input.cpp

@@ -1245,7 +1245,8 @@ Solution Input::solve(const unsigned nb_searches,
     threads.reserve(sol.routes.size());
     std::exception_ptr ep = nullptr;
     std::mutex ep_m;
-    std::counting_semaphore<128> semaphore(nb_thread);
+    std::counting_semaphore<MAX_ROUTING_THREADS> semaphore(
+      std::min(MAX_ROUTING_THREADS, nb_thread));
 
     auto run_routing = [this, &semaphore, &sol, &ep, &ep_m](std::size_t i) {
       semaphore.acquire();