spice: send updates only for changed screen content

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>
This commit is contained in:
Gerd Hoffmann 2012-09-05 10:41:42 +02:00
parent a7310dd34d
commit b021bd2983
1 changed files with 55 additions and 1 deletions

View File

@ -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));
}