[client] app: new options to reduce CPU usage

This patch increases the default cursor and frame polling interval from
1us to 1000us which for most use cases should be more then fast enough.

It also adds two new configuration options to adjust these should it be
required:

  * app:cursorPollInterval
  * app:framePollInterval

VERSION

@@ -1 +1 @@
-a12-205-g087387087e+1
+a12-206-gfc66a4a19c+1

client/src/config.c

@@ -86,6 +86,20 @@ static struct Option options[] =
     .type           = OPTION_TYPE_BOOL,
     .value.x_bool   = false,
   },
+  {
+    .module        = "app",
+    .name          = "cursorPollInterval",
+    .description   = "How often to check for a cursor update in microseconds",
+    .type          = OPTION_TYPE_INT,
+    .value.x_int   = 1000
+  },
+  {
+    .module        = "app",
+    .name          = "framePollInterval",
+    .description   = "How often to check for a frame update in microseconds",
+    .type          = OPTION_TYPE_INT,
+    .value.x_int   = 1000
+  },
 
   // window options
   {
@@ -344,8 +358,10 @@ bool config_load(int argc, char * argv[])
   }
 
   // setup the application params for the basic types
-  params.shmFile       = option_get_string("app", "shmFile");
-  params.shmSize       = option_get_int   ("app", "shmSize") * 1048576;
+  params.shmFile            = option_get_string("app", "shmFile"           );
+  params.shmSize            = option_get_int   ("app", "shmSize"           ) * 1048576;
+  params.cursorPollInterval = option_get_int   ("app", "cursorPollInterval");
+  params.framePollInterval  = option_get_int   ("app", "framePollInterval" );
 
   params.windowTitle   = option_get_string("win", "title"        );
   params.autoResize    = option_get_bool  ("win", "autoResize"   );

client/src/main.c

@@ -171,8 +171,7 @@ static int cursorThread(void * unused)
     {
       if (!state.running)
         return 0;
-
-      usleep(1);
+      usleep(params.cursorPollInterval);
       continue;
     }
 
@@ -285,7 +284,7 @@ static int frameThread(void * unused)
       if (!state.running)
         break;
 
-      usleep(1);
+      usleep(params.framePollInterval);
       continue;
     }
 

client/src/main.h

@@ -96,6 +96,9 @@ struct AppParams
   SDL_Scancode escapeKey;
   bool         showAlerts;
 
+  unsigned int cursorPollInterval;
+  unsigned int framePollInterval;
+
   bool         forceRenderer;
   unsigned int forceRendererIndex;