Re: [Linux-fbdev-devel] [PATCH 1/2] vgacon: optimize scrolling
From: Krzysztof Helt <hidden>
Date: 2008-09-21 18:37:23
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On Sun, 21 Sep 2008 18:00:08 +0200 Marcin Slusarz [off-list ref] wrote:
Join multiple scr_memcpyw into 1-3 calls (usually 2). (benchmarked average speedup: 1%)
The scr_memcpyw is an inline function so there is no real call here. However, have you tested the patch with scroll range > 2 * vgacon_scrollback_size? It seems that your patch only handles scrolling if it is not bigger than 2 * vgacon_scrollback_size. Regards, Krzysztof
quoted hunk ↗ jump to hunk
Signed-off-by: Marcin Slusarz <redacted> Cc: Antonino Daplas <adaplas@gmail.com> Cc: linux-fbdev-devel@lists.sourceforge.net --- drivers/video/console/vgacon.c | 28 ++++++++++++++++------------ 1 files changed, 16 insertions(+), 12 deletions(-)diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c index bd1f57b..de4f66c 100644 --- a/drivers/video/console/vgacon.c +++ b/drivers/video/console/vgacon.c@@ -292,23 +292,27 @@ static int vgacon_scrolldelta(struct vc_data *c, int lines) 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 (soff >= vgacon_scrollback_size) - soff = 0; + 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 (count) { + copysize = min(count, vgacon_scrollback_size); + scr_memcpyw(d, vgacon_scrollback, copysize); + d += copysize; + } } 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;-- 1.5.6.4 ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Linux-fbdev-devel mailing list Linux-fbdev-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-fbdev-devel
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