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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 DAF8AC43603 for ; Fri, 13 Dec 2019 05:32:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B76AB2253D for ; Fri, 13 Dec 2019 05:32:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732079AbfLMFcM (ORCPT ); Fri, 13 Dec 2019 00:32:12 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:5558 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732038AbfLMFcL (ORCPT ); Fri, 13 Dec 2019 00:32:11 -0500 Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id xBD5R395066916 for ; Fri, 13 Dec 2019 00:32:10 -0500 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0b-001b2d01.pphosted.com with ESMTP id 2wurcrcxay-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 13 Dec 2019 00:32:10 -0500 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 13 Dec 2019 05:32:04 -0000 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id xBD5W3mj5177350 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 13 Dec 2019 05:32:03 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 418B8A4060; Fri, 13 Dec 2019 05:32:03 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A5D72A4054; Fri, 13 Dec 2019 05:32:00 +0000 (GMT) Received: from linux.vnet.ibm.com (unknown [9.126.150.29]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with SMTP; Fri, 13 Dec 2019 05:32:00 +0000 (GMT) Date: Fri, 13 Dec 2019 11:02:00 +0530 From: Srikar Dronamraju To: Peter Zijlstra Cc: Dave Chinner , Phil Auld , Ming Lei , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, Jeff Moyer , Dave Chinner , Eric Sandeen , Christoph Hellwig , Jens Axboe , Ingo Molnar , Tejun Heo , Vincent Guittot Subject: Re: [PATCH v4] sched/core: Preempt current task in favour of bound kthread Reply-To: Srikar Dronamraju References: <20191120191636.GI4097@hirez.programming.kicks-ass.net> <20191120220313.GC18056@pauld.bos.csb> <20191121132937.GW4114@hirez.programming.kicks-ass.net> <20191209165122.GA27229@linux.vnet.ibm.com> <20191209231743.GA19256@dread.disaster.area> <20191210054330.GF27253@linux.vnet.ibm.com> <20191210172307.GD9139@linux.vnet.ibm.com> <20191211173829.GB21797@linux.vnet.ibm.com> <20191211224617.GE19256@dread.disaster.area> <20191212101031.GV2827@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20191212101031.GV2827@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) X-TM-AS-GCONF: 00 x-cbid: 19121305-4275-0000-0000-0000038E774F X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19121305-4276-0000-0000-000038A2334E Message-Id: <20191213053200.GA18602@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,18.0.572 definitions=2019-12-12_08:2019-12-12,2019-12-12 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 clxscore=1015 impostorscore=0 lowpriorityscore=0 priorityscore=1501 mlxscore=0 phishscore=0 malwarescore=0 suspectscore=0 adultscore=0 mlxlogscore=710 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1912130045 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org * Peter Zijlstra [2019-12-12 11:10:31]: > On Thu, Dec 12, 2019 at 09:46:17AM +1100, Dave Chinner wrote: > > On Wed, Dec 11, 2019 at 11:08:29PM +0530, Srikar Dronamraju wrote: > > Good point, something to maybe try (Srikar?) is making tick preemption > more agressive for such tasks. > > The below extends the previous patch to retain the set_next_buddy() on > wakeup, but does not make the actual preemption more agressive. > > Then it 'fixes' the tick preemption to better align with the actual > scheduler pick (ie. consider the buddy hints). > Just to let you know, I tried the patch, but it doesn't help. The results were identical to the one without the patch. I think its probably because when we allow the task to stay on the runqueue, it will surely lead to load_balance and so we see the active-balance kick in. Peter, Based on what Dave is asking for, would you be okay if we add 1. A delayed_wake_list per runqueue, 2. A new wake_up API to add tasks to this delayed wake_list 3. On schedule, tasks on the delayed_wake_list would be actually woken up. -- Thanks and Regards Srikar Dronamraju