Configuration and environment variable improvements

nano/lib/threading.cpp

@@ -26,6 +26,7 @@ unsigned nano::hardware_concurrency ()
 		}
 		return std::thread::hardware_concurrency ();
 	}();
+	release_assert (concurrency > 0, "configured hardware concurrency must be non zero");
 	return concurrency;
 }
 

nano/lib/utility.hpp

@@ -285,4 +285,14 @@ std::string to_str (T const & val)
 {
 	return boost::lexical_cast<std::string> (val);
 }
+}
+
+namespace nano
+{
+template <typename T>
+T min_max (T min, T max, T value)
+{
+	debug_assert (min <= max);
+	return std::min (max, std::max (min, value));
+}
 }

nano/node/message_processor.hpp

@@ -17,7 +17,7 @@ class message_processor_config final
 	nano::error serialize (nano::tomlconfig & toml) const;
 
 public:
-	size_t threads{ std::min (nano::hardware_concurrency () / 4, 2u) };
+	size_t threads{ min_max (1u, 2u, nano::hardware_concurrency () / 4) };
 	size_t max_queue{ 64 };
 };
 

nano/node/request_aggregator.hpp

@@ -29,7 +29,7 @@ class request_aggregator_config final
 	nano::error serialize (nano::tomlconfig &) const;
 
 public:
-	size_t threads{ std::min (nano::hardware_concurrency (), 4u) };
+	size_t threads{ min_max (1u, 4u, nano::hardware_concurrency () / 2) };
 	size_t max_queue{ 128 };
 	size_t batch_size{ 16 };
 };

nano/node/vote_processor.hpp

@@ -50,7 +50,7 @@ class vote_processor_config final
 	size_t max_pr_queue{ 256 };
 	size_t max_non_pr_queue{ 32 };
 	size_t pr_priority{ 3 };
-	size_t threads{ std::min (4u, nano::hardware_concurrency () / 2) };
+	size_t threads{ min_max (1u, 4u, nano::hardware_concurrency () / 2) };
 	size_t batch_size{ 1024 };
 };