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.
Signed-off-by: Peter Lieven <p...@kamp.de> --- ui/vnc.c | 146 ++++++++++++++++++++++++++++++++++++++------------------------ ui/vnc.h | 3 ++ 2 files changed, 92 insertions(+), 57 deletions(-) diff --git a/ui/vnc.c b/ui/vnc.c index 67b1f75..edf33be 100644 --- a/ui/vnc.c +++ b/ui/vnc.c @@ -572,6 +572,16 @@ void *vnc_server_fb_ptr(VncDisplay *vd, int x, int y) ptr += x * VNC_SERVER_FB_BYTES; return ptr; } +/* this sets only the visible pixels of a dirty bitmap */ +#define VNC_SET_VISIBLE_PIXELS_DIRTY(bitmap, w, h) {\ + int x, y;\ + memset(bitmap, 0x00, sizeof(bitmap));\ + for (y = 0; y < h; y++) {\ + for (x = 0; x < w / VNC_DIRTY_PIXELS_PER_BIT; x++) {\ + set_bit(x, bitmap[y]);\ + } \ + } \ + } static void vnc_dpy_switch(DisplayChangeListener *dcl, DisplaySurface *surface) @@ -597,7 +607,9 @@ static void vnc_dpy_switch(DisplayChangeListener *dcl, qemu_pixman_image_unref(vd->guest.fb); vd->guest.fb = pixman_image_ref(surface->image); vd->guest.format = surface->format; - memset(vd->guest.dirty, 0xFF, sizeof(vd->guest.dirty)); + VNC_SET_VISIBLE_PIXELS_DIRTY(vd->guest.dirty, + surface_width(vd->ds), + surface_height(vd->ds)); QTAILQ_FOREACH(vs, &vd->clients, next) { vnc_colordepth(vs); @@ -605,7 +617,9 @@ static void vnc_dpy_switch(DisplayChangeListener *dcl, if (vs->vd->cursor) { vnc_cursor_define(vs); } - memset(vs->dirty, 0xFF, sizeof(vs->dirty)); + VNC_SET_VISIBLE_PIXELS_DIRTY(vs->dirty, + surface_width(vd->ds), + surface_height(vd->ds)); } } @@ -882,6 +896,14 @@ static int vnc_update_client_sync(VncState *vs, int has_dirty) return ret; } +#define VNC_CLIENT_UPDATE_RECT() \ + if (last_x != -1) {\ + int h = find_and_clear_dirty_height(vs, y, last_x, x, height);\ + n += vnc_job_add_rect(job,\ + last_x * VNC_DIRTY_PIXELS_PER_BIT, y,\ + (x - last_x) * VNC_DIRTY_PIXELS_PER_BIT, h);\ + } + static int vnc_update_client(VncState *vs, int has_dirty) { if (vs->need_update && vs->csock != -1) { @@ -910,35 +932,32 @@ static int vnc_update_client(VncState *vs, int has_dirty) width = MIN(pixman_image_get_width(vd->server), vs->client_width); height = MIN(pixman_image_get_height(vd->server), vs->client_height); - for (y = 0; y < height; y++) { + y = 0; + for (;;) { int x; int last_x = -1; - for (x = 0; x < width / VNC_DIRTY_PIXELS_PER_BIT; x++) { + unsigned long offset = find_next_bit((unsigned long *) &vs->dirty, + height * VNC_DIRTY_BITS_PER_LINE(vs), + y * VNC_DIRTY_BITS_PER_LINE(vs)); + if (offset == height * VNC_DIRTY_BITS_PER_LINE(vs)) { + /* no more dirty bits */ + break; + } + y = offset / VNC_DIRTY_BITS_PER_LINE(vs); + + for (x = offset % VNC_DIRTY_BITS_PER_LINE(vs); + x < width / VNC_DIRTY_PIXELS_PER_BIT; x++) { if (test_and_clear_bit(x, vs->dirty[y])) { if (last_x == -1) { last_x = x; } } else { - if (last_x != -1) { - int h = find_and_clear_dirty_height(vs, y, last_x, x, - height); - - n += vnc_job_add_rect(job, - last_x * VNC_DIRTY_PIXELS_PER_BIT, - y, - (x - last_x) * VNC_DIRTY_PIXELS_PER_BIT, - h); - } + VNC_CLIENT_UPDATE_RECT(); last_x = -1; } } - if (last_x != -1) { - int h = find_and_clear_dirty_height(vs, y, last_x, x, height); - n += vnc_job_add_rect(job, last_x * VNC_DIRTY_PIXELS_PER_BIT, - y, - (x - last_x) * VNC_DIRTY_PIXELS_PER_BIT, - h); - } + VNC_CLIENT_UPDATE_RECT(); + y++; } vnc_job_push(job); @@ -2676,8 +2695,8 @@ static int vnc_refresh_server_surface(VncDisplay *vd) int width = pixman_image_get_width(vd->guest.fb); int height = pixman_image_get_height(vd->guest.fb); int y; - uint8_t *guest_row; - uint8_t *server_row; + uint8_t *guest_row0 = NULL, *server_row0; + int guest_stride, server_stride; int cmp_bytes; VncState *vs; int has_dirty = 0; @@ -2702,44 +2721,57 @@ static int vnc_refresh_server_surface(VncDisplay *vd) if (vd->guest.format != VNC_SERVER_FB_FORMAT) { int width = pixman_image_get_width(vd->server); tmpbuf = qemu_pixman_linebuf_create(VNC_SERVER_FB_FORMAT, width); - } - guest_row = (uint8_t *)pixman_image_get_data(vd->guest.fb); - server_row = (uint8_t *)pixman_image_get_data(vd->server); - for (y = 0; y < height; y++) { - if (!bitmap_empty(vd->guest.dirty[y], VNC_DIRTY_BITS)) { - int x; - uint8_t *guest_ptr; - uint8_t *server_ptr; + } else { + guest_row0 = (uint8_t *)pixman_image_get_data(vd->guest.fb); + } + server_row0 = (uint8_t *)pixman_image_get_data(vd->server); + guest_stride = pixman_image_get_stride(vd->guest.fb); + server_stride = pixman_image_get_stride(vd->server); + + y = 0; + for (;;) { + int x; + uint8_t *guest_ptr, *server_ptr; + unsigned long offset = find_next_bit((unsigned long *) &vd->guest.dirty, + height * VNC_DIRTY_BITS_PER_LINE(&vd->guest), + y * VNC_DIRTY_BITS_PER_LINE(&vd->guest)); + if (offset == height * VNC_DIRTY_BITS_PER_LINE(&vd->guest)) { + /* no more dirty bits */ + break; + } + y = offset / VNC_DIRTY_BITS_PER_LINE(&vd->guest); - if (vd->guest.format != VNC_SERVER_FB_FORMAT) { - qemu_pixman_linebuf_fill(tmpbuf, vd->guest.fb, width, 0, y); - guest_ptr = (uint8_t *)pixman_image_get_data(tmpbuf); - } else { - guest_ptr = guest_row; - } - server_ptr = server_row; + server_ptr = server_row0 + y * server_stride; - for (x = 0; x + VNC_DIRTY_PIXELS_PER_BIT - 1 < width; - x += VNC_DIRTY_PIXELS_PER_BIT, guest_ptr += cmp_bytes, - server_ptr += cmp_bytes) { - if (!test_and_clear_bit((x / VNC_DIRTY_PIXELS_PER_BIT), - vd->guest.dirty[y])) { - continue; - } - if (memcmp(server_ptr, guest_ptr, cmp_bytes) == 0) { - continue; - } - memcpy(server_ptr, guest_ptr, cmp_bytes); - if (!vd->non_adaptive) - vnc_rect_updated(vd, x, y, &tv); - QTAILQ_FOREACH(vs, &vd->clients, next) { - set_bit((x / VNC_DIRTY_PIXELS_PER_BIT), vs->dirty[y]); - } - has_dirty++; + if (vd->guest.format != VNC_SERVER_FB_FORMAT) { + qemu_pixman_linebuf_fill(tmpbuf, vd->guest.fb, width, 0, y); + guest_ptr = (uint8_t *)pixman_image_get_data(tmpbuf); + } else { + guest_ptr = guest_row0 + y * guest_stride; + } + + for (x = offset % VNC_DIRTY_BITS_PER_LINE(&vd->guest); + x + VNC_DIRTY_PIXELS_PER_BIT - 1 < width; + x += VNC_DIRTY_PIXELS_PER_BIT, guest_ptr += cmp_bytes, + server_ptr += cmp_bytes) { + if (!test_and_clear_bit((x / VNC_DIRTY_PIXELS_PER_BIT), + vd->guest.dirty[y])) { + continue; + } + if (memcmp(server_ptr, guest_ptr, cmp_bytes) == 0) { + continue; + } + memcpy(server_ptr, guest_ptr, cmp_bytes); + if (!vd->non_adaptive) { + vnc_rect_updated(vd, x, y, &tv); } + QTAILQ_FOREACH(vs, &vd->clients, next) { + set_bit((x / VNC_DIRTY_PIXELS_PER_BIT), vs->dirty[y]); + } + has_dirty++; } - guest_row += pixman_image_get_stride(vd->guest.fb); - server_row += pixman_image_get_stride(vd->server); + + y++; } qemu_pixman_image_unref(tmpbuf); return has_dirty; diff --git a/ui/vnc.h b/ui/vnc.h index 4a8f33c..82c8ea8 100644 --- a/ui/vnc.h +++ b/ui/vnc.h @@ -88,6 +88,9 @@ 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_BITS_PER_LINE might be greater than VNC_DIRTY_BITS due to alignment */ +#define VNC_DIRTY_BITS_PER_LINE(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) -- 1.7.9.5