From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D42BC43387 for ; Wed, 9 Jan 2019 17:02:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4235B206B7 for ; Wed, 9 Jan 2019 17:02:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726634AbfAIRCK (ORCPT ); Wed, 9 Jan 2019 12:02:10 -0500 Received: from muru.com ([72.249.23.125]:32818 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726368AbfAIRCK (ORCPT ); Wed, 9 Jan 2019 12:02:10 -0500 Received: from atomide.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id 605A580C5; Wed, 9 Jan 2019 17:02:15 +0000 (UTC) Date: Wed, 9 Jan 2019 09:02:06 -0800 From: Tony Lindgren To: Vincent Guittot Cc: "Rafael J. Wysocki" , "Rafael J. Wysocki" , Ulf Hansson , "open list:THERMAL" , linux-kernel , LAK , Linux OMAP Mailing List , Ladislav Michl Subject: Re: Regression in v5.0-rc1 with autosuspend hrtimers Message-ID: <20190109170206.GS5544@atomide.com> References: <20190108155354.GL5544@atomide.com> <20190108213743.GN5544@atomide.com> <20190109014218.GA8363@linaro.org> <20190109015124.GO5544@atomide.com> <20190109162846.GP5544@atomide.com> <20190109165004.GQ5544@atomide.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.11.1 (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Vincent Guittot [190109 16:56]: > On Wed, 9 Jan 2019 at 17:50, Tony Lindgren wrote: > > > > * Vincent Guittot [190109 16:48]: > > > On Wed, 9 Jan 2019 at 17:28, Tony Lindgren wrote: > > > > > > > > * Rafael J. Wysocki [190109 09:44]: > > > > > On Wed, Jan 9, 2019 at 2:51 AM Tony Lindgren wrote: > > > > > > > > > > > > * Vincent Guittot [190109 01:42]: > > > > > > > Le Tuesday 08 Jan 2019 à 13:37:43 (-0800), Tony Lindgren a écrit : > > > > > > > > Lowering the autosuspend_delay_ms to 2100 ms makes things work again. > > > > > > > > Anything higher than 2200 ms seems to somehow time out immediately > > > > > > > > now :) > > > > > > > > > > > > > > This is quite close to the max ns of an int on arm 32bits > > > > > > > > > > > > > > Could you try the patch below ? > > > > > > > > > > > > Yup great thanks, that's it: > > > > > > > > > > > > Tested-by: Tony Lindgren > > > > > > > > > > Cool. Thanks for getting to the bottom of this! > > > > > > > > No problem. > > > > > > > > One more thing I noticed: The 25% slack can get noticeable > > > > for larger values. For things like a 3 second uart console > > > > timeout slack of 750 ms is quite large variation. > > > > > > > > Should we have a limit of max 100 ms for the slack? > > > > > > Keep in mind that when jiffies were used, expires was rounded to a > > > full second when delay was greater than a second. So you could already > > > have difference of up 990ms on arm before this patch > > > And i don't take into account the rework of timer infra which add > > > another level of variation, something like up to 640 ms more when the > > > timer is greater than 2880 ms for arm IIRC > > > > I think it was rounded up earlier. > > > > Don't we get rounded down now also? > > We still round up. In hrtimer we have : > timer->_softexpires = time; > timer->node.expires = ktime_add_safe(time, delta); > so the hrtimer will expire between "time" and "time+delta" OK thanks for checking it. In that case we should be good to go :) Tony