From: Knut Petersen Date: Fri, 9 Sep 2005 20:04:59 +0000 (-0700) Subject: [PATCH] framebuffer: bit_putcs() optimization for 8x* fonts X-Git-Tag: v2.6.14-rc1~313 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c5eb5c1ea919f3f717236c5d0892f9c37f19de37;p=linux-2.6 [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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/video/console/bitblit.c b/drivers/video/console/bitblit.c index 12eaf0aa87..6550875ef9 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; } }