Use EVLOOP_ONCE in a loop to periodically check the stop flag

Author: fcostaoliveira

client.cpp

@@ -634,7 +634,7 @@ bool verify_client::finished(void)
 ///////////////////////////////////////////////////////////////////////////
 
 client_group::client_group(benchmark_config* config, abstract_protocol *protocol, object_generator* obj_gen) :
-    m_base(NULL), m_config(config), m_protocol(protocol), m_obj_gen(obj_gen)
+    m_base(NULL), m_config(config), m_protocol(protocol), m_obj_gen(obj_gen), m_stop_requested(false)
 {
     m_base = event_base_new();
     assert(m_base != NULL);
@@ -707,7 +707,25 @@ int client_group::prepare(void)
 
 void client_group::run(void)
 {
-    event_base_dispatch(m_base);
+    // Use EVLOOP_ONCE in a loop to periodically check the stop flag
+    // This ensures we can exit promptly when force_stop() is called,
+    // even if there are pending events (like slow responses)
+    struct timeval timeout;
+    timeout.tv_sec = 0;
+    timeout.tv_usec = 100000;  // 100ms timeout
+
+    while (!m_stop_requested.load(std::memory_order_relaxed)) {
+        // Set a timeout so epoll_wait doesn't block indefinitely
+        event_base_loopexit(m_base, &timeout);
+
+        // Run one iteration of the event loop
+        int ret = event_base_loop(m_base, EVLOOP_ONCE);
+
+        // ret == 1 means no more events, ret == -1 means error
+        if (ret != 0) {
+            break;
+        }
+    }
 }
 
 void client_group::interrupt(void)
@@ -725,6 +743,9 @@ void client_group::force_stop(void)
     // Force stop all clients and break event loop for immediate shutdown
     // This is more aggressive than interrupt() - it forcefully cleans up all events
 
+    // Set the stop flag first - this will cause the run() loop to exit
+    m_stop_requested.store(true, std::memory_order_relaxed);
+
     // Mark all clients as interrupted
     set_all_clients_interrupted();
 

client.h

@@ -210,6 +210,7 @@ class client_group {
     abstract_protocol* m_protocol;
     object_generator* m_obj_gen;
     std::vector<client*> m_clients;
+    std::atomic<bool> m_stop_requested;  // Flag to signal the event loop to stop
 public:
     client_group(benchmark_config *cfg, abstract_protocol *protocol, object_generator* obj_gen);
     ~client_group();