Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753107AbdHJN5y (ORCPT ); Thu, 10 Aug 2017 09:57:54 -0400 Received: from mail-he1eur01on0066.outbound.protection.outlook.com ([104.47.0.66]:28672 "EHLO EUR01-HE1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752776AbdHJN5v (ORCPT ); Thu, 10 Aug 2017 09:57:51 -0400 Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=cmetcalf@mellanox.com; Subject: Re: [RFC PATCH 0/9] Introduce housekeeping subsystem To: Frederic Weisbecker Cc: LKML , Peter Zijlstra , Thomas Gleixner , Luiz Capitulino , Christoph Lameter , "Paul E . McKenney" , Ingo Molnar , Mike Galbraith , Rik van Riel , Wanpeng Li References: <1500643290-25842-1-git-send-email-fweisbec@gmail.com> <20170810125437.GA8754@lerouge> From: Chris Metcalf Message-ID: <3398d7d6-74c2-4918-ae3d-aa5a2e3a12dd@mellanox.com> Date: Thu, 10 Aug 2017 09:57:37 -0400 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <20170810125437.GA8754@lerouge> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [209.117.102.182] X-ClientProxiedBy: BN6PR11CA0029.namprd11.prod.outlook.com (2603:10b6:404:4b::15) To HE1PR0501MB2764.eurprd05.prod.outlook.com (2603:10a6:3:c0::18) X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 22c9b1ad-f80b-4f17-f8d4-08d4dff7c8a7 X-MS-Office365-Filtering-HT: Tenant X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:(300000500095)(300135000095)(300000501095)(300135300095)(300000502095)(300135100095)(22001)(2017030254152)(300000503095)(300135400095)(48565401081)(201703131423075)(201703031133081)(201702281549075)(300000504095)(300135200095)(300000505095)(300135600095)(300000506095)(300135500095);SRVR:HE1PR0501MB2764; 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Maybe a CONFIG_HOUSEKEEPING_BOOT_ONLY as a way to restrict housekeeping by default to just the boot cpu. In conjunction with NOHZ_FULL_ALL you would then get the expected semantics. > Also I plan to add a housekeeping option to offload the residual 1Hz tick from > nohz_full CPUs. So having "housekeeping=0,tick_offload" would make CPU 0 the > housekeeper, make the other CPUs nohz_full and handle their 1hz tick from CPU 0. It does seem like that might be implied by requesting NOHZ_FULL on the core... or maybe it's just implied by TASK_ISOLATION. I've done a bad job of finding time to work on that since last year's Plumbers, but September looks good :) -- Chris Metcalf, Mellanox Technologies http://www.mellanox.com