From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751243AbbJXJ7G (ORCPT ); Sat, 24 Oct 2015 05:59:06 -0400 Received: from www.linutronix.de ([62.245.132.108]:38489 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750892AbbJXJ7E (ORCPT ); Sat, 24 Oct 2015 05:59:04 -0400 Date: Sat, 24 Oct 2015 18:58:18 +0900 (KST) From: Thomas Gleixner To: Yang Yingliang cc: Ding Tianhong , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Hanjun Guo Subject: Re: Problem about CPU stalling in hrtimer_intterrupts() In-Reply-To: <5628E7E9.409@huawei.com> Message-ID: References: <56288585.40204@huawei.com> <5628AC58.2030509@huawei.com> <5628E7E9.409@huawei.com> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 22 Oct 2015, Yang Yingliang wrote: > But I found out when the cpu is stalling, basenow.tv64(7676664221321) is > bigger than ktime_get().tv64(7336008904750) in hrtimer_interrupt() and > the timer->_softexpires is 7336288000000. This makes it can not finish > the while loop until ktime_get().tv64 arrives basenow.tv64. > > Is it correct that basenow bigger than ktime_get() ? You only can compare basenow and ktime_get() for the clock monotonic base. If you are actually observing this on clock monotonic base then base->offset of clock monotonic is not 0, which should never happen. Thanks, tglx