From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754938AbYJMVl3 (ORCPT ); Mon, 13 Oct 2008 17:41:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754503AbYJMVlB (ORCPT ); Mon, 13 Oct 2008 17:41:01 -0400 Received: from mail-gx0-f16.google.com ([209.85.217.16]:58875 "EHLO mail-gx0-f16.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754059AbYJMVlA (ORCPT ); Mon, 13 Oct 2008 17:41:00 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; b=Vfgeip+B6LMgwT2e/j26xCSEwqpNjqgNjsUfrVxEcEQRglRlv76sged2ympiLMrIdS erEF4L8/Ph5RkB9WNn/LWwbj1O6iCUx7ZkQphsIxTeMaonChihGBfAQnbV15CyNiMk7L hqsHQM/BHPM9Lt39d30jPI9nuI8RkfokeXimw= Message-ID: <48F3C060.2050302@gmail.com> Date: Mon, 13 Oct 2008 17:40:48 -0400 From: Robert William Fuller User-Agent: Thunderbird 2.0.0.12 (X11/20080513) MIME-Version: 1.0 To: Hans Verkuil CC: =?UTF-8?B?TsOpbWV0aCBNw6FydG9u?= , video4linux-list@redhat.com, LKML Subject: Re: [PATCH 2/2] video: simplify cx18_get_input() and ivtv_get_input() References: <48F3B56E.9050404@freemail.hu> <200810132328.47170.hverkuil@xs4all.nl> In-Reply-To: <200810132328.47170.hverkuil@xs4all.nl> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hans Verkuil wrote: > On Monday 13 October 2008 22:54:06 Németh Márton wrote: >> From: Márton Németh >> >> The cx18_get_input() and ivtv_get_input() are called >> once from the VIDIOC_ENUMINPUT ioctl() and once from >> the *_log_status() functions. In the first case the >> struct v4l2_input is already filled with zeros, >> so doing this again is unnecessary. > > And in the second case no one cares whether the struct is zeroed. And > the same situation is also true for ivtv_get_output(). Yeah, 'cos there's nothing better than uninitialized fields, like the recent report of a control that returns minimum and maximum values of zero, but a step-size of 9. Why are we optimizing code paths that are not performance critical by uninitializing memory? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx3.redhat.com (mx3.redhat.com [172.16.48.32]) by int-mx1.corp.redhat.com (8.13.1/8.13.1) with ESMTP id m9DLf26S002139 for ; Mon, 13 Oct 2008 17:41:02 -0400 Received: from mail-gx0-f15.google.com (mail-gx0-f15.google.com [209.85.217.15]) by mx3.redhat.com (8.13.8/8.13.8) with ESMTP id m9DLewQX014952 for ; Mon, 13 Oct 2008 17:40:59 -0400 Received: by gxk8 with SMTP id 8so3461569gxk.3 for ; Mon, 13 Oct 2008 14:40:58 -0700 (PDT) Message-ID: <48F3C060.2050302@gmail.com> Date: Mon, 13 Oct 2008 17:40:48 -0400 From: Robert William Fuller MIME-Version: 1.0 To: Hans Verkuil References: <48F3B56E.9050404@freemail.hu> <200810132328.47170.hverkuil@xs4all.nl> In-Reply-To: <200810132328.47170.hverkuil@xs4all.nl> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Cc: video4linux-list@redhat.com, LKML , =?UTF-8?B?TsOpbWV0aCBNw6FydG9u?= Subject: Re: [PATCH 2/2] video: simplify cx18_get_input() and ivtv_get_input() List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: video4linux-list-bounces@redhat.com Errors-To: video4linux-list-bounces@redhat.com List-ID: Hans Verkuil wrote: > On Monday 13 October 2008 22:54:06 Németh Márton wrote: >> From: Márton Németh >> >> The cx18_get_input() and ivtv_get_input() are called >> once from the VIDIOC_ENUMINPUT ioctl() and once from >> the *_log_status() functions. In the first case the >> struct v4l2_input is already filled with zeros, >> so doing this again is unnecessary. > > And in the second case no one cares whether the struct is zeroed. And > the same situation is also true for ivtv_get_output(). Yeah, 'cos there's nothing better than uninitialized fields, like the recent report of a control that returns minimum and maximum values of zero, but a step-size of 9. Why are we optimizing code paths that are not performance critical by uninitializing memory? -- video4linux-list mailing list Unsubscribe mailto:video4linux-list-request@redhat.com?subject=unsubscribe https://www.redhat.com/mailman/listinfo/video4linux-list