The patch titled
framebuffer: bit_putcs() optimization for 8x* fonts
has been added to the -mm tree. Its filename is
framebuffer-bit_putcs-optimization-for-8x.patch
Patches currently in -mm which might be from [EMAIL PROTECTED] are
framebuffer-new-driver-for-cyberblade-i1-graphics.patch
framebuffer-bit_putcs-optimization-for-8x.patch
From: Knut Petersen <[EMAIL PROTECTED]>
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 <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---
drivers/video/console/bitblit.c | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)
diff -puN
drivers/video/console/bitblit.c~framebuffer-bit_putcs-optimization-for-8x
drivers/video/console/bitblit.c
---
devel/drivers/video/console/bitblit.c~framebuffer-bit_putcs-optimization-for-8x
2005-08-30 17:52:32.000000000 -0700
+++ devel-akpm/drivers/video/console/bitblit.c 2005-08-30 17:52:32.000000000
-0700
@@ -114,7 +114,7 @@ static void bit_putcs(struct vc_data *vc
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
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;
}
}
_
-
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