Patchwork [04/10] spice: send updates only for changed screen content

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Submitter Gerd Hoffmann
Date Sept. 13, 2012, 8:45 a.m.
Message ID <1347525926-28563-5-git-send-email-kraxel@redhat.com>
Download mbox | patch
Permalink /patch/183570/
State New
Headers show

Comments

Gerd Hoffmann - Sept. 13, 2012, 8:45 a.m.
when creating screen updates go compare the current guest screen
against the mirror (which holds the most recent update sent), then
only create updates for the screen areas which did actually change.

[ v2: drop redundant qemu_spice_create_one_update call ]

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 ui/spice-display.c |   56 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 55 insertions(+), 1 deletions(-)

Patch

diff --git a/ui/spice-display.c b/ui/spice-display.c
index 973cd53..d062765 100644
--- a/ui/spice-display.c
+++ b/ui/spice-display.c
@@ -239,6 +239,13 @@  static void qemu_spice_create_one_update(SimpleSpiceDisplay *ssd,
 
 static void qemu_spice_create_update(SimpleSpiceDisplay *ssd)
 {
+    static const int blksize = 32;
+    int blocks = (ds_get_width(ssd->ds) + blksize - 1) / blksize;
+    int dirty_top[blocks];
+    int y, yoff, x, xoff, blk, bw;
+    int bpp = ds_get_bytes_per_pixel(ssd->ds);
+    uint8_t *guest, *mirror;
+
     if (qemu_spice_rect_is_empty(&ssd->dirty)) {
         return;
     };
@@ -253,7 +260,54 @@  static void qemu_spice_create_update(SimpleSpiceDisplay *ssd)
         ssd->ds_mirror = g_malloc0(size);
     }
 
-    qemu_spice_create_one_update(ssd, &ssd->dirty);
+    for (blk = 0; blk < blocks; blk++) {
+        dirty_top[blk] = -1;
+    }
+
+    guest = ds_get_data(ssd->ds);
+    mirror = ssd->ds_mirror;
+    for (y = ssd->dirty.top; y < ssd->dirty.bottom; y++) {
+        yoff = y * ds_get_linesize(ssd->ds);
+        for (x = ssd->dirty.left; x < ssd->dirty.right; x += blksize) {
+            xoff = x * bpp;
+            blk = x / blksize;
+            bw = MIN(blksize, ssd->dirty.right - x);
+            if (memcmp(guest + yoff + xoff,
+                       mirror + yoff + xoff,
+                       bw * bpp) == 0) {
+                if (dirty_top[blk] != -1) {
+                    QXLRect update = {
+                        .top    = dirty_top[blk],
+                        .bottom = y,
+                        .left   = x,
+                        .right  = x + bw,
+                    };
+                    qemu_spice_create_one_update(ssd, &update);
+                    dirty_top[blk] = -1;
+                }
+            } else {
+                if (dirty_top[blk] == -1) {
+                    dirty_top[blk] = y;
+                }
+            }
+        }
+    }
+
+    for (x = ssd->dirty.left; x < ssd->dirty.right; x += blksize) {
+        blk = x / blksize;
+        bw = MIN(blksize, ssd->dirty.right - x);
+        if (dirty_top[blk] != -1) {
+            QXLRect update = {
+                .top    = dirty_top[blk],
+                .bottom = ssd->dirty.bottom,
+                .left   = x,
+                .right  = x + bw,
+            };
+            qemu_spice_create_one_update(ssd, &update);
+            dirty_top[blk] = -1;
+        }
+    }
+
     memset(&ssd->dirty, 0, sizeof(ssd->dirty));
 }