Re: [Qemu-devel] [PATCH] smoother sdl display & mouse

[Jindrich Makovicka <makovick@gmail.com>]

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On Tue, 24 Jul 2007 19:44:12 +0100
"Daniel P. Berrange" <berrange@redhat.com> wrote:
> Using a command line argument to change the refresh rate doesn't seem
> like a particularly optional solution. It think it would be better to
> have QEMU automatically adapt the refresh rate. eg, it would start
> off refreshing SDL at 30ms  intervals. If it sees a keyboard or mouse
> event, it would increase the refresh rate to 10ms. If, say, 100ms
> passes without any further events, then it could decrease it to 30ms
> again.
> 
> That way everyone would always get the low CPU load, unless they were
> actaully interacting with the mouse/keyboard in which case it would
> tune itself for interactive response.

Sounds reasonable. Updated patch attached.

-- 
Jindrich Makovicka

[-- Attachment #2: kvm-33-refresh.diff --]
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diff -ur kvm-33.orig/qemu/sdl.c kvm-33/qemu/sdl.c
--- kvm-33.orig/qemu/sdl.c	2007-07-23 16:58:51.000000000 +0200
+++ kvm-33/qemu/sdl.c	2007-07-29 16:27:49.000000000 +0200
@@ -43,6 +43,8 @@
 static SDL_Cursor *sdl_cursor_normal;
 static SDL_Cursor *sdl_cursor_hidden;
 static int absolute_enabled = 0;
+static int decimate_counter = 0;
+static int idle_counter = 0;
 
 static void sdl_update(DisplayState *ds, int x, int y, int w, int h)
 {
@@ -311,17 +313,24 @@
     vga_hw_update();
 }
 
+#define SDL_IDLE_THRESHOLD 10
+#define SDL_DECIMATE 3
+
 static void sdl_refresh(DisplayState *ds)
 {
     SDL_Event ev1, *ev = &ev1;
     int mod_state;
+    int was_idle = 1;
                      
     if (last_vm_running != vm_running) {
         last_vm_running = vm_running;
         sdl_update_caption();
     }
 
-    vga_hw_update();
+    if (idle_counter < SDL_IDLE_THRESHOLD || decimate_counter == 0)
+	vga_hw_update();
+
+    decimate_counter = (decimate_counter + 1) % SDL_DECIMATE;
 
     while (SDL_PollEvent(ev)) {
         switch (ev->type) {
@@ -330,6 +339,7 @@
             break;
         case SDL_KEYDOWN:
         case SDL_KEYUP:
+	    was_idle = 0;
             if (ev->type == SDL_KEYDOWN) {
                 mod_state = (SDL_GetModState() & gui_grab_code) ==
                     gui_grab_code;
@@ -428,6 +438,7 @@
             }
             break;
         case SDL_MOUSEMOTION:
+	    was_idle = 0;
             if (gui_grab || kbd_mouse_is_absolute() ||
                 absolute_enabled) {
                 sdl_send_mouse_event(0);
@@ -435,6 +446,7 @@
             break;
         case SDL_MOUSEBUTTONDOWN:
         case SDL_MOUSEBUTTONUP:
+	    was_idle = 0;
             {
                 SDL_MouseButtonEvent *bev = &ev->button;
                 if (!gui_grab && !kbd_mouse_is_absolute()) {
@@ -467,6 +479,13 @@
             break;
         }
     }
+
+    if (was_idle) {
+	if (idle_counter < SDL_IDLE_THRESHOLD)
+	    idle_counter++;
+    } else {
+	idle_counter = 0;
+    }
 }
 
 static void sdl_cleanup(void) 
@@ -504,6 +523,7 @@
     ds->dpy_update = sdl_update;
     ds->dpy_resize = sdl_resize;
     ds->dpy_refresh = sdl_refresh;
+    ds->refresh_interval = 10;
 
     sdl_resize(ds, 640, 400);
     sdl_update_caption();
diff -ur kvm-33.orig/qemu/vl.c kvm-33/qemu/vl.c
--- kvm-33.orig/qemu/vl.c	2007-07-23 16:58:51.000000000 +0200
+++ kvm-33/qemu/vl.c	2007-07-29 17:18:24.000000000 +0200
@@ -110,7 +110,7 @@
 #define DEFAULT_RAM_SIZE 128
 #endif
 /* in ms */
-#define GUI_REFRESH_INTERVAL 30
+#define DEFAULT_GUI_REFRESH_INTERVAL 30
 
 /* Max number of USB devices that can be specified on the commandline.  */
 #define MAX_USB_CMDLINE 8
@@ -4137,6 +4137,7 @@
     ds->dpy_update = dumb_update;
     ds->dpy_resize = dumb_resize;
     ds->dpy_refresh = dumb_refresh;
+    ds->refresh_interval = DEFAULT_GUI_REFRESH_INTERVAL;
 }
 
 /***********************************************************/
@@ -5995,7 +5996,7 @@
 void gui_update(void *opaque)
 {
     display_state.dpy_refresh(&display_state);
-    qemu_mod_timer(gui_timer, GUI_REFRESH_INTERVAL + qemu_get_clock(rt_clock));
+    qemu_mod_timer(gui_timer, display_state.refresh_interval + qemu_get_clock(rt_clock));
 }
 
 struct vm_change_state_entry {
Only in kvm-33/qemu: vl.c~
diff -ur kvm-33.orig/qemu/vl.h kvm-33/qemu/vl.h
--- kvm-33.orig/qemu/vl.h	2007-07-23 16:58:51.000000000 +0200
+++ kvm-33/qemu/vl.h	2007-07-29 16:13:15.000000000 +0200
@@ -907,6 +907,7 @@
     int width;
     int height;
     void *opaque;
+    int refresh_interval;
 
     void (*dpy_update)(struct DisplayState *s, int x, int y, int w, int h);
     void (*dpy_resize)(struct DisplayState *s, int w, int h);