vgacon: optimize scrolling
Join multiple scr_memcpyw into 1-3 calls (usually 2). (benchmarked
average speedup: 1%)
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Cc: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index 6df29a6..3556268 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -292,23 +292,26 @@
d = (void *) c->vc_origin;
s = (void *) c->vc_screenbuf;
- while (count--) {
- scr_memcpyw(d, vgacon_scrollback + soff, c->vc_size_row);
- d += c->vc_size_row;
- soff += c->vc_size_row;
+ if (count) {
+ int copysize;
+ count *= c->vc_size_row;
+ /* how much memory to end of buffer left? */
+ copysize = min(count, vgacon_scrollback_size - soff);
+ scr_memcpyw(d, vgacon_scrollback + soff, copysize);
+ d += copysize;
+ count -= copysize;
- if (soff >= vgacon_scrollback_size)
- soff = 0;
+ if (count) {
+ scr_memcpyw(d, vgacon_scrollback, count);
+ d += count;
+ }
}
if (diff == c->vc_rows) {
vgacon_cursor(c, CM_MOVE);
} else {
- while (diff--) {
- scr_memcpyw(d, s, c->vc_size_row);
- d += c->vc_size_row;
- s += c->vc_size_row;
- }
+ if (diff)
+ scr_memcpyw(d, s, diff * c->vc_size_row);
}
return 1;