From: Antti Palosaari <crope@iki.fi>
To: Devin Heitmueller <dheitmueller@kernellabs.com>
Cc: Hans Verkuil <hverkuil@xs4all.nl>,
Linux Media Mailing List <linux-media@vger.kernel.org>
Subject: Re: [PATCH RFC] libv4lconvert: SDR conversion from U8 to FLOAT
Date: Fri, 15 Nov 2013 21:17:21 +0200 [thread overview]
Message-ID: <52867341.7050500@iki.fi> (raw)
In-Reply-To: <CAGoCfiz8EBqkEUuzYLXhgXGW-0S6+6s3MAFWdSpfFmuOnP+Dfg@mail.gmail.com>
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
--
http://palosaari.fi/
next prev parent reply other threads:[~2013-11-15 19:17 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-10 17:16 [PATCH RFC] libv4lconvert: SDR conversion from U8 to FLOAT Antti Palosaari
2013-11-11 13:14 ` Hans Verkuil
2013-11-11 13:40 ` Antti Palosaari
2013-11-11 13:52 ` Hans Verkuil
2013-11-15 19:11 ` Antti Palosaari
2013-11-15 19:13 ` Devin Heitmueller
2013-11-15 19:17 ` Antti Palosaari [this message]
2013-11-16 14:11 ` Antti Palosaari
2013-11-16 17:28 ` Hans de Goede
2013-11-11 14:19 ` Andy Walls
2013-11-11 14:38 ` Hans Verkuil
2013-11-14 13:45 ` Antti Palosaari
2013-11-14 13:50 ` Hans Verkuil
2013-11-18 17:43 ` Antti Palosaari
2013-11-16 17:27 ` Hans de Goede
2013-11-16 17:34 ` Antti Palosaari
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