realtime: wake the interpreter from a dedicated timer thread

core/hostevents_sdl.cpp

@@ -38,6 +38,7 @@ void EventManager::set_keyboard_locale(uint32_t keyboard_id) {
 
 void EventManager::poll_events() {
     SDL_Event event;
+    bool host_input = false; // set when an input event is delivered to the guest
 
     while (SDL_PollEvent(&event)) {
         events_captured++;
@@ -189,6 +190,7 @@ void EventManager::poll_events() {
                         key_ups++;
                     }
 
+                    host_input = true;
                     this->_keyboard_signal.emit(ke);
                     ke.key = AdbKey_Delete;
                     this->_keyboard_signal.emit(ke);
@@ -210,6 +212,7 @@ void EventManager::poll_events() {
                         ke.flags = event.key.keysym.mod & KMOD_CAPS ?
                             KEYBOARD_EVENT_DOWN : KEYBOARD_EVENT_UP;
                     }
+                    host_input = true;
                     this->_keyboard_signal.emit(ke);
                 } else {
                     LOG_F(WARNING, "Unknown key %x pressed", event.key.keysym.sym);
@@ -224,6 +227,7 @@ void EventManager::poll_events() {
                 me.xabs  = event.motion.x;
                 me.yabs  = event.motion.y;
                 me.flags = MOUSE_EVENT_MOTION;
+                host_input = true;
                 this->_mouse_signal.emit(me);
             }
             break;
@@ -241,6 +245,7 @@ void EventManager::poll_events() {
                 me.xabs  = event.button.x;
                 me.yabs  = event.button.y;
                 me.flags = MOUSE_EVENT_BUTTON;
+                host_input = true;
                 this->_mouse_signal.emit(me);
             }
             break;
@@ -258,6 +263,7 @@ void EventManager::poll_events() {
                 me.xabs  = event.button.x;
                 me.yabs  = event.button.y;
                 me.flags = MOUSE_EVENT_BUTTON;
+                host_input = true;
                 this->_mouse_signal.emit(me);
             }
             break;
@@ -281,6 +287,7 @@ void EventManager::poll_events() {
                 }
                 ge.gamepad_id = event.cbutton.which;
                 ge.flags = GAMEPAD_EVENT_DOWN;
+                host_input = true;
                 this->_gamepad_signal.emit(ge);
             }
             break;
@@ -304,6 +311,7 @@ void EventManager::poll_events() {
                 }
                 ge.gamepad_id = event.cbutton.which;
                 ge.flags = GAMEPAD_EVENT_UP;
+                host_input = true;
                 this->_gamepad_signal.emit(ge);
             }
             break;
@@ -315,6 +323,9 @@ void EventManager::poll_events() {
 
     // perform post-processing
     this->_post_signal.emit();
+
+    if (host_input)
+        mark_host_input();
 }
 
 void EventManager::post_keyboard_state_events() {

core/timermanager.cpp

@@ -131,6 +131,15 @@ uint64_t TimerManager::process_timers()
     return cur_timer->timeout_ns - time_now;
 }
 
+uint64_t TimerManager::get_next_timeout_ns()
+{
+    std::lock_guard<std::recursive_mutex> lk(this->timer_queue.get_mtx());
+    if (this->timer_queue.empty()) {
+        return 0ULL;
+    }
+    return this->timer_queue.top()->timeout_ns;
+}
+
 void TimerManager::cancel_all_timers()
 {
     std::shared_ptr<TimerInfo> cur_timer;

core/timermanager.h

@@ -141,6 +141,10 @@ class TimerManager {
 
     uint64_t process_timers();
 
+    // peek at the next timer's expiry (in guest time) without firing it;
+    // returns 0 if there are no pending timers
+    uint64_t get_next_timeout_ns();
+
 private:
     static TimerManager* timer_manager;
     TimerManager(){} // private constructor to implement a singleton

cpu/ppc/ppcemu.h

@@ -344,6 +344,11 @@ enum Exc_Cause : uint32_t {
 
 extern unsigned exec_flags;
 
+// Counter of guest accesses to memory-mapped devices, incremented by
+// mmu_read_vmem/mmu_write_vmem. Used by ppcexec.cpp to detect when the
+// guest is idling (spinning without touching any device).
+extern uint64_t g_mmio_access_count;
+
 extern jmp_buf exc_env;
 
 enum Po_Cause : int {
@@ -728,6 +733,16 @@ extern int get_icnt_factor();
 /* toggle_g_realtime */
 extern bool toggle_g_realtime();
 
+/* set_g_idle_cpu_save */
+extern void set_g_idle_cpu_save(bool enabled);
+
+/* mark_host_input: the host event poller calls this for every input event */
+extern void mark_host_input();
+
+/* realtime timer thread */
+extern void start_realtime_timer_thread();
+extern void stop_realtime_timer_thread();
+
 /* force_cycle_counter_reload */
 static void force_cycle_counter_reload();