From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261882AbULGSlB (ORCPT ); Tue, 7 Dec 2004 13:41:01 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261884AbULGSlB (ORCPT ); Tue, 7 Dec 2004 13:41:01 -0500 Received: from out001pub.verizon.net ([206.46.170.140]:15077 "EHLO out001.verizon.net") by vger.kernel.org with ESMTP id S261882AbULGSkp (ORCPT ); Tue, 7 Dec 2004 13:40:45 -0500 From: Gene Heskett Reply-To: gene.heskett@verizon.net Organization: Organization: None, detectable by casual observers To: linux-kernel@vger.kernel.org Subject: Re: [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm2-V0.7.32-2 Date: Tue, 7 Dec 2004 13:40:42 -0500 User-Agent: KMail/1.7 Cc: Ingo Molnar , Eran Mann References: <41B5C038.1090501@mrv.com> <20041207153720.GA20712@elte.hu> In-Reply-To: <20041207153720.GA20712@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8bit Content-Disposition: inline Message-Id: <200412071340.42731.gene.heskett@verizon.net> X-Authentication-Info: Submitted using SMTP AUTH at out001.verizon.net from [141.153.76.102] at Tue, 7 Dec 2004 12:40:43 -0600 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 07 December 2004 10:37, Ingo Molnar wrote: >* Eran Mann wrote: >> On my machine, disabling CONFIG_LATENCY_TRACE causes the kernel to >> stop reporting preempt latencies. After >> >> # echo 1 > /proc/sys/kernel/preempt_max_latency >> >> /proc/sys/kernel/preempt_max_latency always shows 1 no matter what >> load is on the machine. I´ve seen this behavior since the first >> time I tried to disable CONFIG_LATENCY_TRACE, around >> V0.7.31.something. > >indeed - there was a thinko in trace_stop_sched_switched() that > likely caused this problem. Does the -32-8 patch (freshly uploaded) > work better for you? > > Ingo I'd like to report a slight improvement in the reports from tvtime while running 32-6 with full preemtion turned on, cfq scheduler: ------ Dec 7 13:29:39 coyote kernel: wow! That was a 15 millisec bump Dec 7 13:29:39 coyote kernel: `IRQ 8'[838] is being piggy. need_resched=0, cpu=0 Dec 7 13:29:39 coyote kernel: Read missed before next interrupt ----- Each second of the log contains about 27 of these, so its pretty steady. Picture looks pretty good though. Although, that particular snip was taken from the log while I was *not* on the same screen as tvtime. Switching back it its screen returned the slip times to the 22 millisecond area. And on quiting, this was output: ----------------- Dec 7 13:29:47 coyote kernel: rtc latency histogram of {tvtime/4038, 7565 samples}: Dec 7 13:29:47 coyote kernel: 3 401 Dec 7 13:29:47 coyote kernel: 4 3348 Dec 7 13:29:47 coyote kernel: 5 1104 Dec 7 13:29:47 coyote kernel: 6 435 Dec 7 13:29:47 coyote kernel: 7 294 Dec 7 13:29:47 coyote kernel: 8 246 Dec 7 13:29:47 coyote kernel: 9 236 Dec 7 13:29:47 coyote kernel: 10 241 Dec 7 13:29:47 coyote kernel: 11 301 Dec 7 13:29:47 coyote kernel: 12 232 Dec 7 13:29:47 coyote kernel: 13 146 Dec 7 13:29:47 coyote kernel: 14 52 Dec 7 13:29:47 coyote kernel: 15 9 Dec 7 13:29:47 coyote kernel: 16 4 Dec 7 13:29:47 coyote kernel: 17 2 Dec 7 13:29:47 coyote kernel: 19 1 Dec 7 13:29:47 coyote kernel: 20 1 Dec 7 13:29:47 coyote kernel: 23 1 Dec 7 13:29:47 coyote kernel: 24 1 Dec 7 13:29:47 coyote kernel: 4545 1 Dec 7 13:29:47 coyote kernel: 9999 509 So there not much real change after all. Heavy duty wishfull thinking I guess. How can I decode the above output into english? -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) 99.30% setiathome rank, not too shabby for a WV hillbilly Yahoo.com attorneys please note, additions to this message by Gene Heskett are: Copyright 2004 by Maurice Eugene Heskett, all rights reserved.