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| author | Knut Petersen <Knut_Petersen@t-online.de> | 2005-09-10 00:04:59 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-09-10 00:58:02 +0400 |
| commit | c5eb5c1ea919f3f717236c5d0892f9c37f19de37 (patch) | |
| tree | 33e48218a7a49576120876a09ead5f1366576861 | |
| parent | 9fa68eae9f8291a98bfe00b94b78f72eb253165a (diff) | |
| download | linux-c5eb5c1ea919f3f717236c5d0892f9c37f19de37.tar.xz | |
[PATCH] framebuffer: bit_putcs() optimization for 8x* fonts
This trivial patch gives a performance boost to the framebuffer console
Constructing the bitmaps that are given to the bitblit functions of the
framebuffer drivers is time consuming. Here we avoide a call to the slow
fb_pad_aligned_buffer(). The patch replaces that call with a simple but
much more efficient bytewise copy.
The kernel spends a significant time at this place if you use 8x* fonts.
Every pixel displayed on your screen is prepared here.
Some benchmark results:
Displaying a file of 2000 lines with 160 characters each takes 889 ms
system time using cyblafb on my system (I´m using a 1280x1024 video mode,
resulting in a 160x64 character console)
Displaying the same file with the enclosed patch applied to 2.6.13 only
takes 760 ms system time, saving 129 ms or 14.5%.
Font widths other than 8 are not affected.
The advantage and correctness of this patch should be obvious.
Signed-off-by: Knut Petersen <Knut_Petersen@t-online.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | drivers/video/console/bitblit.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/video/console/bitblit.c b/drivers/video/console/bitblit.c index 12eaf0aa87e6..6550875ef9c5 100644 --- a/drivers/video/console/bitblit.c +++ b/drivers/video/console/bitblit.c @@ -114,7 +114,7 @@ static void bit_putcs(struct vc_data *vc, struct fb_info *info, unsigned int scan_align = info->pixmap.scan_align - 1; unsigned int buf_align = info->pixmap.buf_align - 1; unsigned int shift_low = 0, mod = vc->vc_font.width % 8; - unsigned int shift_high = 8, pitch, cnt, size, k; + unsigned int shift_high = 8, pitch, cnt, size, i, k; unsigned int idx = vc->vc_font.width >> 3; unsigned int attribute = get_attribute(info, scr_readw(s)); struct fb_image image; @@ -175,7 +175,11 @@ static void bit_putcs(struct vc_data *vc, struct fb_info *info, src = buf; } - fb_pad_aligned_buffer(dst, pitch, src, idx, image.height); + if (idx == 1) + for(i=0; i < image.height; i++) + dst[pitch*i] = src[i]; + else + fb_pad_aligned_buffer(dst, pitch, src, idx, image.height); dst += width; } } |