On Nov 18, 2013 12:20 AM, "Peter Lieven" <p...@kamp.de> wrote: > > 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>
Can you include performance data? Regards, Anthony Liguori > --- > 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 > >