From d40fbf8d52ae6c9b7fe9d76eeab624afc3a3f1ea Mon Sep 17 00:00:00 2001 From: Kirill Smelkov Date: Fri, 2 Nov 2012 09:10:33 -0300 Subject: [PATCH] [media] vivi: Optimize precalculate_line() precalculate_line() is not very high on profile, but it calls expensive gen_twopix(), so let's polish it too: call gen_twopix() only once for every color bar and then distribute the result. before: # cmdline : /home/kirr/local/perf/bin/perf record -g -a sleep 20 # # Samples: 46K of event 'cycles' # Event count (approx.): 15574200568 # # Overhead Command Shared Object # ........ ............... .................... # 27.99% rawv libc-2.13.so [.] __memcpy_ssse3 23.29% vivi-* [kernel.kallsyms] [k] memcpy 10.30% Xorg [unknown] [.] 0xa75c98f8 5.34% vivi-* [vivi] [k] gen_text.constprop.6 4.61% rawv [vivi] [k] gen_twopix 2.64% rawv [vivi] [k] precalculate_line 1.37% swapper [kernel.kallsyms] [k] read_hpet after: # cmdline : /home/kirr/local/perf/bin/perf record -g -a sleep 20 # # Samples: 45K of event 'cycles' # Event count (approx.): 15561769214 # # Overhead Command Shared Object # ........ ............... .................... # 30.73% rawv libc-2.13.so [.] __memcpy_ssse3 26.78% vivi-* [kernel.kallsyms] [k] memcpy 10.68% Xorg [unknown] [.] 0xa73015e9 5.55% vivi-* [vivi] [k] gen_text.constprop.6 1.36% swapper [kernel.kallsyms] [k] read_hpet 0.96% Xorg [kernel.kallsyms] [k] read_hpet ... 0.16% rawv [vivi] [k] precalculate_line ... 0.14% rawv [vivi] [k] gen_twopix (i.e. gen_twopix and precalculate_line overheads are almost gone) Signed-off-by: Kirill Smelkov Acked-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- drivers/media/platform/vivi.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/drivers/media/platform/vivi.c b/drivers/media/platform/vivi.c index ec832e9461a8..7abb046e0fa5 100644 --- a/drivers/media/platform/vivi.c +++ b/drivers/media/platform/vivi.c @@ -512,12 +512,22 @@ static void gen_twopix(struct vivi_dev *dev, u8 *buf, int colorpos, bool odd) static void precalculate_line(struct vivi_dev *dev) { - int w; - - for (w = 0; w < dev->width * 2; w++) { - int colorpos = w / (dev->width / 8) % 8; - - gen_twopix(dev, dev->line + w * dev->pixelsize, colorpos, w & 1); + unsigned pixsize = dev->pixelsize; + unsigned pixsize2 = 2*pixsize; + int colorpos; + u8 *pos; + + for (colorpos = 0; colorpos < 16; ++colorpos) { + u8 pix[8]; + int wstart = colorpos * dev->width / 8; + int wend = (colorpos+1) * dev->width / 8; + int w; + + gen_twopix(dev, &pix[0], colorpos % 8, 0); + gen_twopix(dev, &pix[pixsize], colorpos % 8, 1); + + for (w = wstart/2*2, pos = dev->line + w*pixsize; w < wend; w += 2, pos += pixsize2) + memcpy(pos, pix, pixsize2); } } -- 2.30.2