for bug #237, never sleep when thread interval is 0.

@@ -129,9 +129,9 @@ public:
 };
 };
 
 
 /**
 /**
- * the publish recv thread got message and callback the source method to process message.
+* the publish recv thread got message and callback the source method to process message.
 * @see: https://github.com/winlinvip/simple-rtmp-server/issues/237
 * @see: https://github.com/winlinvip/simple-rtmp-server/issues/237
- */
+*/
 class SrsPublishRecvThread : public ISrsMessageHandler
 class SrsPublishRecvThread : public ISrsMessageHandler
 {
 {
 private:
 private:

@@ -179,8 +179,12 @@ failed:
             break;
             break;
         }
         }
         
         
+        // to improve performance, donot sleep when interval is zero.
+        // @see: https://github.com/winlinvip/simple-rtmp-server/issues/237
+        if (cycle_interval_us > 0) {
             st_usleep(cycle_interval_us);
             st_usleep(cycle_interval_us);
         }
         }
+    }
     
     
     handler->on_thread_stop();
     handler->on_thread_stop();
     srs_info("thread cycle finished");
     srs_info("thread cycle finished");