From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264401AbUEXTgS (ORCPT ); Mon, 24 May 2004 15:36:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264389AbUEXTgS (ORCPT ); Mon, 24 May 2004 15:36:18 -0400 Received: from mail.tmr.com ([216.238.38.203]:35077 "EHLO gatekeeper.tmr.com") by vger.kernel.org with ESMTP id S264401AbUEXTgL (ORCPT ); Mon, 24 May 2004 15:36:11 -0400 To: linux-kernel@vger.kernel.org Path: not-for-mail From: Bill Davidsen Newsgroups: mail.linux-kernel Subject: Re: tvtime and the Linux 2.6 scheduler Date: Mon, 24 May 2004 15:38:45 -0400 Organization: TMR Associates, Inc Message-ID: References: <20040523154859.GC22399@dumbterm.net> <20040523224908.25194.qmail@web40607.mail.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Trace: gatekeeper.tmr.com 1085427156 30927 192.168.12.100 (24 May 2004 19:32:36 GMT) X-Complaints-To: abuse@tmr.com User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6b) Gecko/20031208 X-Accept-Language: en-us, en In-Reply-To: <20040523224908.25194.qmail@web40607.mail.yahoo.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org szonyi calin wrote: > --- Billy Biggs a écrit : > I am the > author of tvtime, a TV application with advanced > >>image >>processing algorithms. Some users are complaining about poor >>performance under Linux 2.6, and I would like more information >>about how >>tvtime will be treated by the scheduler. Here is an example >>of the >>intended usage: >> >> - Program running as root and SCHED_FIFO >> - NTSC, input ~30 fps, each field processed for an output of ~60 fps ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^ >> - CPU intensive processing, say 9 ms per field on my P3-733 >> - with a typical AGP card, the X driver takes 4 ms to draw >> - Wait using /dev/rtc set to 1024 Hz >> >> for(;;) >> 9 ms : process frame >> 4 ms : draw frame >> 3 ms : wait until next field time using /dev/rtc >> 9 ms : process frame >> 4 ms : draw frame >> 3 ms : block on /dev/video0 for next frame >> ----- >> 33 ms : time per NTSC frame [___snip___] > For me it works ok > Running tvtime with 2.6.6-mm5 load average 26 (twenty six) it > works > almost perfect (no frame skipped -- at least not reported by > tvtime) > at full rate (50 frames/sec). Computer: AMD Duron 700 MHz, 256MB ~~~~~~~~~~~~~~~~^^^ > Ram, > VIA KT133 chipset, AGP 4x, Ati Radeon 7200 There have been pretty good explanations of this, so I'll just say that it might be that someone with a machine of limited capacity would be able to generate 50fps and not 60fps. In much of Europe the TV flickers at the same frequency as the lights ;-) -- -bill davidsen (davidsen@tmr.com) "The secret to procrastination is to put things off until the last possible moment - but no longer" -me