From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kapsi.fi ([217.30.184.167]:57224 "EHLO mail.kapsi.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751268Ab3KOTRY (ORCPT ); Fri, 15 Nov 2013 14:17:24 -0500 Message-ID: <52867341.7050500@iki.fi> Date: Fri, 15 Nov 2013 21:17:21 +0200 From: Antti Palosaari MIME-Version: 1.0 To: Devin Heitmueller CC: Hans Verkuil , Linux Media Mailing List Subject: Re: [PATCH RFC] libv4lconvert: SDR conversion from U8 to FLOAT References: <1384103776-4788-1-git-send-email-crope@iki.fi> <5280D83C.5060809@xs4all.nl> <5280DE3D.5040408@iki.fi> <528671DF.7040707@iki.fi> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On 15.11.2013 21:13, Devin Heitmueller wrote: > On Fri, Nov 15, 2013 at 2:11 PM, Antti Palosaari 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/