修正 recv timeout 接口cpu占用过高的问题

Author: mutouyun

src/libipc/platform/waiter_linux.h

@@ -224,8 +224,6 @@ class sem_helper {
     static bool wait(handle_t h, std::size_t tm = invalid_value) {
         if (h == invalid()) return false;
         switch (tm) {
-        case 0:
-            return true;
         case invalid_value:
             IPC_SEMAPHORE_FUNC_(sem_wait, h);
         default: {

src/libipc/waiter_helper.h

@@ -13,7 +13,7 @@ namespace detail {
 struct waiter_helper {
 
     struct wait_counter {
-        std::atomic<unsigned> waiting_ { 0 };
+        std::atomic<long> waiting_ { 0 };
         long counter_ = 0;
     };
 
@@ -40,7 +40,7 @@ struct waiter_helper {
         {
             IPC_UNUSED_ auto guard = ctrl.get_lock();
             if (!std::forward<F>(pred)()) return true;
-            counter.counter_ += 1;
+            counter.counter_ = counter.waiting_.load(std::memory_order_relaxed);
         }
         mtx.unlock();
 
@@ -69,6 +69,11 @@ struct waiter_helper {
         return ret;
     }
 
+    template <typename Ctrl>
+    static void clear_handshake(Ctrl & ctrl) {
+        while (ctrl.handshake_wait(0)) ;
+    }
+
     template <typename Ctrl>
     static bool notify(Ctrl & ctrl) {
         auto & counter = ctrl.counter();
@@ -77,6 +82,7 @@ struct waiter_helper {
         }
         bool ret = true;
         IPC_UNUSED_ auto guard = ctrl.get_lock();
+        clear_handshake(ctrl);
         if (counter.counter_ > 0) {
             ret = ctrl.sema_post(1);
             counter.counter_ -= 1;
@@ -93,11 +99,13 @@ struct waiter_helper {
         }
         bool ret = true;
         IPC_UNUSED_ auto guard = ctrl.get_lock();
+        clear_handshake(ctrl);
         if (counter.counter_ > 0) {
             ret = ctrl.sema_post(counter.counter_);
+            auto tm = default_timeout / counter.counter_;
             do {
                 counter.counter_ -= 1;
-                ret = ret && ctrl.handshake_wait(default_timeout);
+                ret = ret && ctrl.handshake_wait(tm);
             } while (counter.counter_ > 0);
         }
         return ret;
@@ -116,6 +124,7 @@ struct waiter_helper {
         }
         bool ret = true;
         IPC_UNUSED_ auto guard = ctrl.get_lock();
+        clear_handshake(ctrl);
         if (counter.counter_ > 0) {
             ret = ctrl.sema_post(counter.counter_);
             counter.counter_ -= 1;