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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 73002C433DF for ; Mon, 29 Jun 2020 21:35:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4052F20759 for ; Mon, 29 Jun 2020 21:35:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593466514; bh=vDqH4OQik9QBHRoYPIsS115Se7LvewJkoA+wC/XILJ8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=RYhIF4BXPFOy+Kzc472uDgRI9NuBIHlQ3fyu7jTz02J4x88xBOHmAVXpsaoiTuY2W BGfHPyy5CgscmckVmGhcLkwTGikqaINB/KyOAvs4Da1OD1KFJLoTyZ7YkvhSGZ5cOW H9XKdVT6Vvr5wSKGfHO8RP1T29hhvi8mdx8ePs8M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728984AbgF2VfN (ORCPT ); Mon, 29 Jun 2020 17:35:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:60600 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728529AbgF2Sky (ORCPT ); Mon, 29 Jun 2020 14:40:54 -0400 Received: from localhost (lfbn-ncy-1-996-218.w90-101.abo.wanadoo.fr [90.101.73.218]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 54B8E23D24; Mon, 29 Jun 2020 12:42:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593434530; bh=vDqH4OQik9QBHRoYPIsS115Se7LvewJkoA+wC/XILJ8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=04ef066Nl1RVmJ0rEQuLCUxIe74aNZT94SXMcWmBJpt8ieJLaRiuiPf01/phg/pRn cwsQ8o70pdRXGfjV7aiVEDSYjYr+B/VlEQvBhNdQABAmIitvNHFdXFvu5FutYwDCMl yFxuImOmuk9k1S/icL0Ln6ggd0ghKrEIiR1lHDhc= Date: Mon, 29 Jun 2020 14:42:08 +0200 From: Frederic Weisbecker To: Juri Lelli Cc: fweisbec@gmail.com, tglx@linutronix.de, mingo@kernel.org, linux-rt-users@vger.kernel.org, peterz@infradead.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] tick/sched: update full_nohz status after SCHED dep is cleared Message-ID: <20200629124207.GA6088@lenoir> References: <20200520162400.GA8800@lenoir> <20200520164925.GM10078@localhost.localdomain> <20200520170215.GB8800@lenoir> <20200520184710.GO10078@localhost.localdomain> <20200521004443.GB15455@lenoir> <20200521170020.GQ10078@localhost.localdomain> <20200615210743.GA21371@lenoir> <20200616065757.GA446382@localhost.localdomain> <20200616204649.GA4914@lenoir> <20200629123651.GA9670@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200629123651.GA9670@localhost.localdomain> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-rt-users-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org On Mon, Jun 29, 2020 at 02:36:51PM +0200, Juri Lelli wrote: > Hi, > > On 16/06/20 22:46, Frederic Weisbecker wrote: > > On Tue, Jun 16, 2020 at 08:57:57AM +0200, Juri Lelli wrote: > > > Sure. Let me know if you find anything. > > > > I managed to reproduce. With "threadirqs" and without > > "tsc=reliable". I see tons of spurious TIMER softirqs. > > Investigation begins! I'll let you know. > > Gentle ping. Any new findings about this issue? Yep, I'm working on a series to reduce timer softirqs. I'm almost done, should post it soon. I believe you guessed right: * Timer tick raises timer softirq * Ksoftirqd wakes up, restarts the tick * Timer tick raises timer softirq * ... Thanks.