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authorKnut Petersen <Knut_Petersen@t-online.de>2005-09-09 13:04:59 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-09-09 13:58:02 -0700
commitc5eb5c1ea919f3f717236c5d0892f9c37f19de37 (patch)
tree33e48218a7a49576120876a09ead5f1366576861 /drivers/video
parent9fa68eae9f8291a98bfe00b94b78f72eb253165a (diff)
downloadop-kernel-dev-c5eb5c1ea919f3f717236c5d0892f9c37f19de37.zip
op-kernel-dev-c5eb5c1ea919f3f717236c5d0892f9c37f19de37.tar.gz
[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>
Diffstat (limited to 'drivers/video')
-rw-r--r--drivers/video/console/bitblit.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/video/console/bitblit.c b/drivers/video/console/bitblit.c
index 12eaf0a..6550875 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;
}
}
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