Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261662AbUKOSlZ (ORCPT ); Mon, 15 Nov 2004 13:41:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261663AbUKOSlZ (ORCPT ); Mon, 15 Nov 2004 13:41:25 -0500 Received: from dfw-gate3.raytheon.com ([199.46.199.232]:59936 "EHLO dfw-gate3.raytheon.com") by vger.kernel.org with ESMTP id S261662AbUKOSlS (ORCPT ); Mon, 15 Nov 2004 13:41:18 -0500 To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Lee Revell , Rui Nuno Capela , "K.R. Foley" , Bill Huey , Adam Heath , Florian Schmidt , Thomas Gleixner , Michal Schmidt , Fernando Pablo Lopez-Lezcano , Karsten Wiese , Gunther Persoons , emann@mrv.com, Shane Shrybman , Amit Shah From: Mark_H_Johnson@raytheon.com Subject: Re: [patch] Real-Time Preemption, -RT-2.6.10-rc1-mm3-V0.7.25-1 Date: Mon, 15 Nov 2004 12:40:08 -0600 Message-ID: X-MIMETrack: Serialize by Router on RTSHOU-DS01/RTS/Raytheon/US(Release 6.5.2|June 01, 2004) at 11/15/2004 12:40:11 PM MIME-Version: 1.0 Content-type: text/plain; charset=US-ASCII X-SPAM: 0.00 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3181 Lines: 70 Didn't see an announcement for V0.7.26, so I'll post this summary under this title. Built today with V0.7.26-4 without any problems. System booted up and telnet 5 was uneventful as well. Ran two series of tests with latencytest and my stress tests with the following results: [1] Appear to have a new symptom of 200 usec delays at raw_read_unlock which doesn't make any sense to me. Have included a latency trace at the end of this message with an example. An occasional 100 usec hit I understand (disk DMA) but I don't recall seeing this symptom before. [2] Still get the symptoms with truncated trace output and bad ping responses. Refer to my previous messages for examples. [3] The logging script (sleep 5 seconds, record data if slept for over 10 seconds) was triggered about 30 times in an hour of testing. None have the huge load average values reported last time but several have 1 minute load averages above 15 (expect 6-8). [4] All of the tests have bursts of long application level delays. I'll be running another test program to see if I can find anything with the user level tracing. Disk activity seems to make it worse but all the tests had at least one CPU delay over a millisecond. There seems to be a "short" (well > 500 usec) delay related to disk reads and a longer one for disk writes. [5] System after testing was done had a major "time shift" as noted in the system log. Nov 15 12:33:55 dws77 ntpd[2359]: synchronized to 192.52.216.4, stratum=3 Nov 15 12:33:57 dws77 ntpd[2359]: synchronized to 192.52.216.1, stratum=2 Nov 15 12:33:36 dws77 ntpd[2359]: time reset -21.466037 s Nov 15 12:33:36 dws77 ntpd[2359]: frequency error -512 PPM exceeds tolerance 500 PPM No crashes nor any major stability problems. --Mark --- 200 usec latency example --- preemption latency trace v1.0.7 on 2.6.10-rc1-mm3-RT-V0.7.26-4 ------------------------------------------------------- latency: 206 us, entries: 12 (12) | [VP:0 KP:1 SP:1 HP:1 #CPUS:2] ----------------- | task: kjournald/1209, uid:0 nice:0 policy:0 rt_prio:0 ----------------- => started at: __down_mutex+0x3f/0x300 => ended at: __down_mutex+0x1a6/0x300 =======> 1209 80000000 0.000ms (+0.002ms): __down_mutex (__spin_lock) 1209 80000000 0.002ms (+0.001ms): _raw_spin_lock (__down_mutex) 1209 80000000 0.004ms (+0.000ms): _raw_spin_lock (__down_mutex) 1209 80000000 0.004ms (+0.000ms): do_nmi (__down_mutex) 1209 80000000 0.005ms (+0.000ms): do_nmi (mcount) 1209 80000000 0.005ms (+0.000ms): do_nmi (<00200286>) 1209 80000000 0.006ms (+0.000ms): profile_hook (profile_tick) 1209 80000000 0.006ms (+0.000ms): _raw_read_lock (profile_hook) 1209 80000000 0.007ms (+0.196ms): _raw_read_unlock (profile_tick) 1209 80000000 0.204ms (+0.001ms): set_new_owner (__down_mutex) 1209 80000000 0.205ms (+0.000ms): _raw_spin_unlock (__down_mutex) 1209 80000000 0.205ms (+0.000ms): _raw_spin_unlock (__down_mutex) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/