Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756379AbXHBHd3 (ORCPT ); Thu, 2 Aug 2007 03:33:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753374AbXHBHdW (ORCPT ); Thu, 2 Aug 2007 03:33:22 -0400 Received: from mailhub.sw.ru ([195.214.233.200]:41301 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753107AbXHBHdV (ORCPT ); Thu, 2 Aug 2007 03:33:21 -0400 Message-ID: <46B1A51C.3040402@sw.ru> Date: Thu, 02 Aug 2007 13:34:20 +0400 From: Vasily Averin Organization: SW-soft User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.8.0.10) Gecko/20070301 SUSE/1.8_seamonkey_1.0.8-0.1 SeaMonkey/1.0.8 MIME-Version: 1.0 To: john stultz CC: lkml , Andrew Morton , devel@openvz.org, Thomas Gleixner Subject: broken timer on VIA K8T800 chipset? References: <46AD57BF.8090106@sw.ru> <1f1b08da0707301113r173adba0yd2585263e89fd8@mail.gmail.com> <1f1b08da0707301807h62a24b3o786beed607ae5fcd@mail.gmail.com> <46AEBDDD.2020107@sw.ru> In-Reply-To: <46AEBDDD.2020107@sw.ru> Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1524 Lines: 36 Vasily Averin wrote: > john stultz wrote: >> On 7/29/07, Vasily Averin wrote: >>> I've investigated why my testnode freezes. When I found that node is freezed >>> again I've started to press Sysrq keys and noticed the following negative time jump. I've found the reason of timer-related issue on the node. I've noticed that number of timer interrupts is not changed (irq 0 in /proc/interrupts). Timer interrupt is not works, jiffies is not not incremented and timers cannot awake. xtime and wall_to_monolitic are not changed, but ktime_get() returns non-constant values because of __get_realtime_clock_ts corrects nanoseconds. Correction vaule is different for various clocksourcses: for "tsc" clocksource it is more noticeable (~4400 sec on my node). Obviously for other clocksources correction value is not too big. When correction value overflows we can observe negative time jump. On the other hand timers are not critical for schedulers work, it uses readtsc for timestaps and therefore node is not hangs completely. However Now I have new question: why timer can hangs on VIA K8T800 chipset? How is possible to fix or at least workaround this issue? I've try to disable irqbalance -- probably it will make the node more stable. thank you, Vasily Averin - 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/