As we have all source codes
what do you advice ?
On Tue, Apr 9, 2013 at 10:38 AM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
> On Tue 9 April 2013 09:58:33 Michal Lazo wrote:
>> I want to make API that will provide hw video decoder on Amlogic SOC
>> it is ARM cortex 9
>>
>> with some proprietary video decoder
>>
>> amlogic provide me with working example that generate output frames in
>> amlvideo driver.
>> It is v4l2 driver
>> and it did memcpy to mmap userspace memory
>>
>> buffer_y_start=ioremap(cs0.addr,cs0.width*cs0.height);
>> for(i=0;i<buf->vb.height;i++) {
>> memcpy(vbuf + pos_dst, buffer_y_start+pos_src, buf->vb.width*3);
>> pos_dst+=buf->vb.width*3;
>> pos_src+= cs0.width;
>> }
>>
>> I did it with one memcpy with same cpu load
>>
>> https://github.com/Pivosgroup/buildroot-linux-kernel/blob/master/drivers/media/video/amlvideo/amlvideo.c#L218
>>
>> top get me 50% cpu load on this driver for 25fps PAL
>>
>> it is really too much
>>
>> and funny is that vivi driver(amlvideo is completely base on vivi) get
>> me same cpu load
>
> Well, yes, because it is the memcpy that gives you all the load.
> Of course, in a well-written driver the amlvideo buffers would be available
> to userspace directly using mmap() and no memcpy would be needed.
>
> Basically amlogic gave you a crappy driver.
>
> Regards,
>
> Hans
>
>>
>> it looks like memcpy isn't cached or something but I don't know how to
>> identify problem
>> Any idea how to identify this problem.
>>
>> On Mon, Apr 8, 2013 at 2:46 PM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
>> > On Mon April 8 2013 14:42:32 Michal Lazo wrote:
>> >> Hi
>> >> 720x576 RGB 25, 30 fps and it take
>> >>
>> >> 25% cpu load on raspberry pi(ARM 700Mhz linux 3.6.11) or 8% on x86(AMD
>> >> 2GHz linux 3.2.0-39)
>> >>
>> >> it is simply too much
>> >
>> > No, that's what I would expect. Note that vivi was substantially improved recently
>> > when it comes to the image generation. That will be in the upcoming 3.9 kernel.
>> >
>> > This should reduce CPU load by quite a bit if memory serves.
>> >
>> > Regards,
>> >
>> > Hans
>> >
>> >>
>> >>
>> >>
>> >>
>> >> On Mon, Apr 8, 2013 at 9:42 AM, Peter Senna Tschudin
>> >> <peter.senna@xxxxxxxxx> wrote:
>> >> > Dear Michal,
>> >> >
>> >> > The CPU intensive part of the vivi driver is the image generation.
>> >> > This is not an issue for real drivers.
>> >> >
>> >> > Regards,
>> >> >
>> >> > Peter
>> >> >
>> >> > On Sun, Apr 7, 2013 at 9:32 PM, Michal Lazo <michal.lazo@xxxxxxxxxxx> wrote:
>> >> >> Hi
>> >> >> V4L2 driver vivi
>> >> >> generate 25% cpu load on raspberry pi(linux 3.6.11) or 8% on x86(linux 3.2.0-39)
>> >> >>
>> >> >> player
>> >> >> GST_DEBUG="*:3,v4l2src:3,v4l2:3" gst-launch-0.10 v4l2src
>> >> >> device="/dev/video0" norm=255 ! video/x-raw-rgb, width=720,
>> >> >> height=576, framerate=30000/1001 ! fakesink sync=false
>> >> >>
>> >> >> Anybody can answer me why?
>> >> >> And how can I do it better ?
>> >> >>
>> >> >> I use vivi as base example for my driver
>> >> >> --
>> >> >> To unsubscribe from this list: send the line "unsubscribe linux-media" in
>> >> >> the body of a message to majordomo@xxxxxxxxxxxxxxx
>> >> >> More majordomo info at http://vger.kernel.org/majordomo-info.html
>> >> >
>> >> >
>> >> >
>> >> > --
>> >> > Peter
>> >>
>> >>
>> >>
>> >>
>>
>>
>>
>>
--
Best Regards
Michal Lazo
Senior developer manager
mdragon.org
Slovakia
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