# \[PATCH 0/2\] vgacon\_scrolldelta cleanup - Subsystems: FRAMEBUFFER LAYER, CONSOLE SUBSYSTEM, THE REST - Maintainers: Helge Deller, Greg Kroah-Hartman, Linus Torvalds - Series: 2 patches touching 1 file, +25/-25 - List: linux-fbdev - 5 messages, 2 authors - Page: https://ratatoskr.run/linux-fbdev/2008/09/1153032/t ## \[PATCH 0/2\] vgacon\_scrolldelta cleanup - From: Marcin Slusarz \ - Date: 2008-09-21 16:00:43 - Message: https://ratatoskr.run/linux-fbdev/2008/09/1153032.md ```text [PATCH 1/2] vgacon: optimize scrolling [PATCH 2/2] vgacon: vgacon_scrolldelta simplification drivers/video/console/vgacon.c | 48 ++++++++++++++++++++-------------------- 1 files changed, 24 insertions(+), 24 deletions(-) ``` ## \[PATCH 1/2\] vgacon: optimize scrolling - From: Marcin Slusarz \ - Date: 2008-09-21 16:01:19 - Message: https://ratatoskr.run/linux-fbdev/2008/09/1153034.md ```text Join multiple scr_memcpyw into 1-3 calls (usually 2). (benchmarked average speedup: 1%) Signed-off-by: Marcin Slusarz Cc: Antonino Daplas Cc: --- 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 ``` ## \[PATCH 2/2\] vgacon: vgacon\_scrolldelta simplification - From: Marcin Slusarz \ - Date: 2008-09-21 16:01:33 - Message: https://ratatoskr.run/linux-fbdev/2008/09/1153035.md ```text There's no point in checking diff == c->vc_rows, because it can be true only when count == 0, but we already checked that. Additionally move variables used only in one block to this block. Signed-off-by: Marcin Slusarz Cc: Antonino Daplas Cc: --- drivers/video/console/vgacon.c | 22 +++++++++------------- 1 files changed, 9 insertions(+), 13 deletions(-) diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c index de4f66c..a785f99 100644 --- a/drivers/video/console/vgacon.c +++ b/drivers/video/console/vgacon.c @@ -239,8 +239,7 @@ static void vgacon_restore_screen(struct vc_data *c) static int vgacon_scrolldelta(struct vc_data *c, int lines) { - int start, end, count, soff, diff; - void *d, *s; + int start, end, count, soff; if (!lines) { c->vc_visible_origin = c->vc_origin; @@ -287,13 +286,13 @@ static int vgacon_scrolldelta(struct vc_data *c, int lines) if (count > c->vc_rows) count = c->vc_rows; - diff = c->vc_rows - count; - - d = (void *) c->vc_origin; - s = (void *) c->vc_screenbuf; - if (count) { int copysize; + + int diff = c->vc_rows - count; + void *d = (void *) c->vc_origin; + void *s = (void *) c->vc_screenbuf; + count *= c->vc_size_row; /* how much memory to end of buffer left? */ copysize = min(count, vgacon_scrollback_size - soff); @@ -306,14 +305,11 @@ static int vgacon_scrolldelta(struct vc_data *c, int lines) scr_memcpyw(d, vgacon_scrollback, copysize); d += copysize; } - } - - if (diff == c->vc_rows) { - vgacon_cursor(c, CM_MOVE); - } else { + if (diff) scr_memcpyw(d, s, diff * c->vc_size_row); - } + } else + vgacon_cursor(c, CM_MOVE); return 1; } -- 1.5.6.4 ``` ## Re: \[Linux-fbdev-devel\] \[PATCH 1/2\] vgacon: optimize scrolling - From: Krzysztof Helt \ - Date: 2008-09-21 18:37:23 - Message: https://ratatoskr.run/linux-fbdev/2008/09/1153053.md ```text On Sun, 21 Sep 2008 18:00:08 +0200 Marcin Slusarz [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 > Signed-off-by: Marcin Slusarz > Cc: Antonino Daplas > Cc: > --- > 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 > ---------------------------------------------------------------------- Kredyt Hipoteczny w Banku Millennium - zdobywca Zlotego Lauru Klienta! Sprawdz >> http://link.interia.pl/f1f15 ``` ## Re: \[Linux-fbdev-devel\] \[PATCH 1/2\] vgacon: optimize scrolling - From: Marcin Slusarz \ - Date: 2008-09-21 21:23:16 - Message: https://ratatoskr.run/linux-fbdev/2008/09/1153139.md ```text On Sun, Sep 21, 2008 at 08:37:57PM +0200, Krzysztof Helt wrote: > On Sun, 21 Sep 2008 18:00:08 +0200 > Marcin Slusarz [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. ... or it's defined to memcpy > 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. No. count is always within range <0, c->vc_rows> (look how it's computed just before this loop). Second copy is needed only when end of screen crosses end/beginning of scrollback (it's a circular buffer). > Regards, > Krzysztof > > > Signed-off-by: Marcin Slusarz > > Cc: Antonino Daplas > > Cc: > > --- > > 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 ```