Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753074AbaGHCke (ORCPT ); Mon, 7 Jul 2014 22:40:34 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:29452 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752386AbaGHCkd (ORCPT ); Mon, 7 Jul 2014 22:40:33 -0400 Message-ID: <53BB5A13.1070305@huawei.com> Date: Tue, 8 Jul 2014 10:40:19 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 MIME-Version: 1.0 To: "xiaofeng.yan" CC: Peter Zijlstra , , , , Juri Lelli Subject: Re: [PATCH] sched/rt: overrun could happen in start_hrtick_dl References: <1404475341-22536-1-git-send-email-xiaofeng.yan@huawei.com> <20140707084150.GC19379@twins.programming.kicks-ass.net> <53BB4510.5090704@huawei.com> In-Reply-To: <53BB4510.5090704@huawei.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.18.230] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2014/7/8 9:10, xiaofeng.yan wrote: > On 2014/7/7 16:41, Peter Zijlstra wrote: >> On Fri, Jul 04, 2014 at 12:02:21PM +0000, xiaofeng.yan wrote: >>> It could be wrong for the precision of runtime and deadline >>> when the precision is within microsecond level. For example: >>> Task runtime deadline period >>> P1 200us 500us 500us >>> >>> This case need enbale HRTICK feature by the next command >>> PC#echo "HRTICK" > /sys/kernel/debug/sched_features >>> PC#./schedtool -E -t 200000:500000 -e ./test& >>> PC#trace-cmd record -e sched_switch >> Are you actually using HRTICK ? > yes, If HRTICK is close , then all of runtime and deadline will be wrong. I think what peter meant is, do you use HRTICK in products or just use it for testing/experiment? -- 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/