diff --git a/src/include/thread_pool.hpp b/src/include/thread_pool.hpp
index 4bf030c..08ca077 100644
--- a/src/include/thread_pool.hpp
+++ b/src/include/thread_pool.hpp
@@ -15,7 +15,7 @@ class ThreadPool
 {
 public:
     ThreadPool():
-        thread_num_(std::thread::hardware_concurrency() * 2),
+        thread_num_(std::thread::hardware_concurrency()),
         is_running_(false) {}
 
     ~ThreadPool() noexcept
diff --git a/src/main.cpp b/src/main.cpp
index 0c06c71..9af8a85 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -18,8 +18,8 @@
 
 namespace fs = std::filesystem;
 
-cxxpool::ThreadPool thread_pool;
-cxxlog::Logger logger;
+static cxxpool::ThreadPool thread_pool;
+static cxxlog::Logger logger;
 
 void processFileTask(fs::path filePath, fs::path outputFolder)
 {