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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 28F6FC433F5 for ; Mon, 14 Feb 2022 09:52:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343600AbiBNJxD (ORCPT ); Mon, 14 Feb 2022 04:53:03 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:60860 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245606AbiBNJt5 (ORCPT ); Mon, 14 Feb 2022 04:49:57 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D6597A1A8 for ; Mon, 14 Feb 2022 01:41:07 -0800 (PST) Received: from dggpeml500023.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Jxzhl1g6kzccyW; Mon, 14 Feb 2022 17:39:51 +0800 (CST) Received: from dggpeml500003.china.huawei.com (7.185.36.200) by dggpeml500023.china.huawei.com (7.185.36.114) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Mon, 14 Feb 2022 17:40:55 +0800 Received: from [10.174.177.173] (10.174.177.173) by dggpeml500003.china.huawei.com (7.185.36.200) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Mon, 14 Feb 2022 17:40:55 +0800 Message-ID: Date: Mon, 14 Feb 2022 17:40:55 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.4.0 Subject: Re: Question about nohz and sysidle Content-Language: en-US From: Yu Liao CC: , , References: To: In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.177.173] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggpeml500003.china.huawei.com (7.185.36.200) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sorry, I sent to the old email address. On 2022/2/14 16:28, Yu Liao wrote: > Hi Frederic, > > I'm working on an issue about nohz. When NO_HZ_FULL is enabled, CPU 0 > handles the timekeeping duty on behalf of all other CPUs, which means > CPU 0 never stop tick even in sysidle state. This is a powersaving issue. > > I found your patchset (nohz: Support sysidle) in the below link. > https://lore.kernel.org/all/1406569056-30217-1-git-send-email-fweisbec@gmail.com/ > > But these patches haven't been merged into mainline yet and sysidle > state detection has been removed by commit fe5ac724d81a (rcu: Remove > nohz_full full-system-idle state machine) as well. > > I tried your patches and it does work, why are we no longer > working on stopping timekeeping duty when all full dynticks CPUs are idle? > > Thanks, > Yu