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=MAILING_LIST_MULTI,SPF_PASS, 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 40306C46475 for ; Mon, 5 Nov 2018 17:29:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1278D20827 for ; Mon, 5 Nov 2018 17:29:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1278D20827 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730137AbeKFCuQ (ORCPT ); Mon, 5 Nov 2018 21:50:16 -0500 Received: from mx2.suse.de ([195.135.220.15]:33860 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729692AbeKFCuP (ORCPT ); Mon, 5 Nov 2018 21:50:15 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 33867B0B7; Mon, 5 Nov 2018 17:29:32 +0000 (UTC) Date: Mon, 5 Nov 2018 18:29:31 +0100 From: Michal Hocko To: Daniel Jordan Cc: linux-mm@kvack.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, aarcange@redhat.com, aaron.lu@intel.com, akpm@linux-foundation.org, alex.williamson@redhat.com, bsd@redhat.com, darrick.wong@oracle.com, dave.hansen@linux.intel.com, jgg@mellanox.com, jwadams@google.com, jiangshanlai@gmail.com, mike.kravetz@oracle.com, Pavel.Tatashin@microsoft.com, prasad.singamsetty@oracle.com, rdunlap@infradead.org, steven.sistare@oracle.com, tim.c.chen@intel.com, tj@kernel.org, vbabka@suse.cz Subject: Re: [RFC PATCH v4 00/13] ktask: multithread CPU-intensive kernel work Message-ID: <20181105172931.GP4361@dhcp22.suse.cz> References: <20181105165558.11698-1-daniel.m.jordan@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181105165558.11698-1-daniel.m.jordan@oracle.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 05-11-18 11:55:45, Daniel Jordan wrote: > Michal, you mentioned that ktask should be sensitive to CPU utilization[1]. > ktask threads now run at the lowest priority on the system to avoid disturbing > busy CPUs (more details in patches 4 and 5). Does this address your concern? > The plan to address your other comments is explained below. I have only glanced through the documentation patch and it looks like it will be much less disruptive than the previous attempts. Now the obvious question is how does this behave on a moderately or even busy system when you compare that to a single threaded execution. Some numbers about best/worst case execution would be really helpful. I will look closer later. -- Michal Hocko SUSE Labs