From mboxrd@z Thu Jan 1 00:00:00 1970 From: Knut Petersen Subject: [PATCH 1/1 2.6.13] framebuffer: bit_putcs() optimization for 8x* fonts Date: Tue, 30 Aug 2005 18:15:12 +0200 Message-ID: <43148610.70406@t-online.de> Mime-Version: 1.0 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: Cc: "Antonino A. Daplas" , linux-fbdev-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Jochen Hein This trivial patch gives a performance boost to the framebuffer console Constructing the bitmaps that are given to the bitblit functions of the= =20 framebuffer drivers is time consuming. Here we avoide a call to the slow=20 fb_pad_aligned_buffer(). The patch replaces that call with a simple but much more efficient=20 bytewise copy. The kernel spends a significant time at this place if you use 8x* fonts= =2E=20 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=20 system time using cyblafb on my system (I=B4m 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= =20 takes 760 ms system time, saving 129 ms or 14.5%. =46ont widths other than 8 are not affected. The advantage and correctness of this patch should be obvious. Signed-off-by: Knut Petersen diff -uprN -X linux/Documentation/dontdiff -x '*.bak' -x '*.ctx' linuxo= rig/drivers/video/console/bitblit.c linux/drivers/video/console/bitblit= =2Ec --- linuxorig/drivers/video/console/bitblit.c 2005-08-29 01:41:01.00000= 0000 +0200 +++ linux/drivers/video/console/bitblit.c 2005-08-30 17:19:57.000000000= +0200 @@ -114,7 +114,7 @@ static void bit_putcs(struct vc_data *vc unsigned int scan_align =3D info->pixmap.scan_align - 1; unsigned int buf_align =3D info->pixmap.buf_align - 1; unsigned int shift_low =3D 0, mod =3D vc->vc_font.width % 8; - unsigned int shift_high =3D 8, pitch, cnt, size, k; + unsigned int shift_high =3D 8, pitch, cnt, size, i, k; unsigned int idx =3D vc->vc_font.width >> 3; unsigned int attribute =3D get_attribute(info, scr_readw(s)); struct fb_image image; @@ -175,7 +175,11 @@ static void bit_putcs(struct vc_data *vc src =3D buf; } =20 - fb_pad_aligned_buffer(dst, pitch, src, idx, image.height); + if (idx =3D=3D 1) + for(i=3D0; i < image.height; i++) + dst[pitch*i] =3D src[i]; + else + fb_pad_aligned_buffer(dst, pitch, src, idx, image.height); dst +=3D width; } }