This patch optimizes SDL updates by keeping track of which parts of the guest
screen have been written since last update and calling SDL_BlitSurface() and
SDL_UpdateRect() for only changed parts of the screen.
Cc: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: John Floren <john@xxxxxxxxxxx>
Cc: Sasha Levin <levinsasha928@xxxxxxxxx>
Signed-off-by: Pekka Enberg <penberg@xxxxxxxxxx>
---
tools/kvm/ui/sdl.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 57 insertions(+), 3 deletions(-)
diff --git a/tools/kvm/ui/sdl.c b/tools/kvm/ui/sdl.c
index bc69ed9..f175a60 100644
--- a/tools/kvm/ui/sdl.c
+++ b/tools/kvm/ui/sdl.c
@@ -6,11 +6,51 @@
#include <SDL/SDL.h>
#include <pthread.h>
+#include <linux/kernel.h>
+
#define FRAME_RATE 25
+static u64 min_x;
+static u64 min_y;
+static u64 max_x;
+static u64 max_y;
+
+static void sdl__finish(void)
+{
+ max_x = 0;
+ max_y = 0;
+ min_x = ULLONG_MAX;
+ min_y = ULLONG_MAX;
+}
+
+static inline bool sdl__need_update(void)
+{
+ return min_x < max_x && min_y < max_y;
+}
+
static void sdl__write(struct framebuffer *fb, u64 addr, u8 *data, u32 len)
{
- memcpy(&fb->mem[addr - fb->mem_addr], data, len);
+ u64 x, y;
+ u64 pos;
+
+ pos = addr - fb->mem_addr;
+
+ x = (pos / 4) % fb->width;
+ y = ((pos / 4) - x) / fb->width;
+
+ if (x < min_x)
+ min_x = x;
+
+ if (y < min_y)
+ min_y = y;
+
+ if (x > max_x)
+ max_x = x;
+
+ if (y > max_y)
+ max_y = y;
+
+ memcpy(&fb->mem[pos], data, len);
}
static void *sdl__thread(void *p)
@@ -40,9 +80,23 @@ static void *sdl__thread(void *p)
if (!screen)
die("Unable to set SDL video mode");
+ sdl__finish();
+
for (;;) {
- SDL_BlitSurface(guest_screen, NULL, screen, NULL);
- SDL_UpdateRect(screen, 0, 0, 0, 0);
+ if (sdl__need_update()) {
+ SDL_Rect rect = {
+ .x = min_x,
+ .y = min_y,
+ .w = max_x - min_x,
+ .h = max_y - min_y,
+ };
+
+ SDL_BlitSurface(guest_screen, &rect, screen, &rect);
+ SDL_UpdateRect(screen, rect.x, rect.y, rect.w, rect.h);
+ }
+
+ sdl__finish();
+
while (SDL_PollEvent(&ev)) {
switch (ev.type) {
case SDL_QUIT:
--
1.7.0.4
--
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