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authorPeter Lieven <pl@kamp.de>2014-01-08 10:08:35 +0100
committerGerd Hoffmann <kraxel@redhat.com>2014-03-10 12:35:04 +0100
commit12b316d4c173bf07f421ef9dc98ba4b53916066e (patch)
tree843e39ea377bb7cf66421dada6656aa43ca5c8af /ui/vnc.h
parent6cd859aa8a7fb60fe6edb89e628cddfe25dfe186 (diff)
ui/vnc: optimize dirty bitmap tracking
vnc_update_client currently scans the dirty bitmap of each client bitwise which is a very costly operation if only few bits are dirty. vnc_refresh_server_surface does almost the same. this patch optimizes both by utilizing the heavily optimized function find_next_bit to find the offset of the next dirty bit in the dirty bitmaps. The following artifical test (just the bitmap operation part) running vnc_update_client 65536 times on a 2560x2048 surface illustrates the performance difference: All bits clean - vnc_update_client_new: 0.07 secs vnc_update_client_old: 10.98 secs All bits dirty - vnc_update_client_new: 11.26 secs vnc_update_client_old: 20.19 secs Few bits dirty - vnc_update_client_new: 0.08 secs vnc_update_client_old: 10.98 secs The case for all bits dirty is still rather slow, this is due to the implementation of find_and_clear_dirty_height. This will be addresses in a separate patch. Signed-off-by: Peter Lieven <pl@kamp.de> Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Diffstat (limited to 'ui/vnc.h')
-rw-r--r--ui/vnc.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/ui/vnc.h b/ui/vnc.h
index a379aab852..8da81b8d6e 100644
--- a/ui/vnc.h
+++ b/ui/vnc.h
@@ -88,6 +88,10 @@ typedef void VncSendHextileTile(VncState *vs,
/* VNC_DIRTY_BITS is the number of bits in the dirty bitmap. */
#define VNC_DIRTY_BITS (VNC_MAX_WIDTH / VNC_DIRTY_PIXELS_PER_BIT)
+/* VNC_DIRTY_BPL (BPL = bits per line) might be greater than
+ * VNC_DIRTY_BITS due to alignment */
+#define VNC_DIRTY_BPL(x) (sizeof((x)->dirty) / VNC_MAX_HEIGHT * BITS_PER_BYTE)
+
#define VNC_STAT_RECT 64
#define VNC_STAT_COLS (VNC_MAX_WIDTH / VNC_STAT_RECT)
#define VNC_STAT_ROWS (VNC_MAX_HEIGHT / VNC_STAT_RECT)