Re: [PATCH RFC] libv4lconvert: SDR conversion from U8 to FLOAT

[Antti Palosaari <crope@iki.fi>]

On 15.11.2013 21:13, Devin Heitmueller wrote:
> On Fri, Nov 15, 2013 at 2:11 PM, Antti Palosaari <crope@iki.fi> wrote:
>> When I do it inside Kernel, in URB completion handler at the same time when
>> copying data to videobuf2, using pre-calculated LUTs and using mmap it eats
>> 0.5% CPU to transfer stream to app.
>>
>> When I do same but using libv4lconvert as that patch, it takes ~11% CPU.
>
> How are you measuring?  Interrupt handlers typically don't count
> toward the CPU performance counters.  It's possible that the cost is
> the same but you're just not seeing it in "top".

Yes, using top and it is URB interrupt handler where I do conversion. So 
any idea how to measure? I think I can still switch LUT to float and see 
if it makes difference.

regards
Antti

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