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authorKirill Smelkov <kirr@mns.spb.ru>2012-11-02 09:10:33 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2012-12-21 18:25:57 -0200
commitd40fbf8d52ae6c9b7fe9d76eeab624afc3a3f1ea (patch)
treeb227ff245d8911052e1f6dbca65dbb08bdfbba34 /drivers/media/platform
parent13908f330f91996b6d59355aa7860553dd1093d5 (diff)
[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 <kirr@mns.spb.ru> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/platform')
-rw-r--r--drivers/media/platform/vivi.c22
1 files 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);
}
}

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