Received: by 2002:a05:7208:13ce:b0:7f:395a:35b6 with SMTP id r14csp260086rbe; Wed, 28 Feb 2024 20:51:26 -0800 (PST) X-Forwarded-Encrypted: i=3; AJvYcCWzZ36qXlmFXdzQT3BKwv8QOZeHuOV+MM1qg+yWMLraHxURauNeqztm2S/tIJn3SJbRv9DYpMdNvsTxUFTbGhQLX1hccXOIi9uJBA8l3w== X-Google-Smtp-Source: AGHT+IEPPhIumiinJQPUk+ZCOauImWKUNGQd5kGZoymylCHngHLycZbjBqoM1rgyIV38BoVNs03m X-Received: by 2002:a05:6512:1190:b0:513:2643:873d with SMTP id g16-20020a056512119000b005132643873dmr357898lfr.36.1709182283320; Wed, 28 Feb 2024 20:51:23 -0800 (PST) ARC-Seal: i=2; a=rsa-sha256; t=1709182283; cv=pass; d=google.com; s=arc-20160816; b=zLt8PZcgS5rUquXs18MxKW6HNv7fXsdeBEie46Fwf8OEUMt3EqrxDJ/qUjc0pLDq11 rpejlRU1cu6UOIPlB1JQnQa9o9ng8D0WkBnBP584XOj0G3dEJwFrdT7dds4WoSUn8YeH vv4wd585nLLdhRvSQ7upXlZlC0lXzWCBS9mKIcOpO9PnM0EhEqv9r3NNohL0k1lLGpI1 hkC6kTg7xeQiT9SENp9btUdb5vXgcXdsfzsjocDkKu+2LQcjnomPhUweEcXJLDpzcxiD PquUW/NjYwngVo31GAe4XHnwTV7hINjIipnG7h4y6zISowf0wnBshc1sOGNXZSyU7cdm V5xg== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:list-unsubscribe :list-subscribe:list-id:precedence:date:message-id:dkim-signature; bh=F1j6OMAur2EReyq9uj1aosLkqEbI8SlT5bNl5MURpv4=; fh=FZgMEvxUSygVXrP65SWIG0qVHGRxXk6KETQmK+BJCOU=; b=nTWW99+220x+R9IQOYz8ZHPB5eCy6+YJr6C0oCh8h+5ZP9qF627w1W98XRLSuUQ0uM Hy6194SZTTSgSjve3A/NcfUU/aHinlXrCQEKpY9k0V4v+jU5hYgeYwJ4nanL7JIshjdl VGKhsFH6dweEGvICqLYVMa88PXfwvqRCvsA6WcPNr8Td7UEP5m24AeMn825F1Gj2dtw7 dv+aS6V0PITL6neUJE5N1tpITosGs7FaIj5hiYWdCTeErEyjG3Y3eHYtKyRtvO9cC3lY e+rARv0wJJh2tEzmfdPuG7z8etfkNFDFHj5tf87OqALob75sOCUG9wsSwCNbkdDzxOuJ lqUQ==; dara=google.com ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@ibm.com header.s=pp1 header.b=jqE252JX; arc=pass (i=1 spf=pass spfdomain=linux.ibm.com dkim=pass dkdomain=ibm.com dmarc=pass fromdomain=linux.ibm.com); spf=pass (google.com: domain of linux-kernel+bounces-86124-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) smtp.mailfrom="linux-kernel+bounces-86124-linux.lists.archive=gmail.com@vger.kernel.org"; dmarc=pass (p=REJECT sp=NONE dis=NONE) header.from=ibm.com Return-Path: Received: from am.mirrors.kernel.org (am.mirrors.kernel.org. [2604:1380:4601:e00::3]) by mx.google.com with ESMTPS id z22-20020a05640235d600b00566a66b681csi98047edc.262.2024.02.28.20.51.23 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Feb 2024 20:51:23 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-86124-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3; Authentication-Results: mx.google.com; dkim=pass header.i=@ibm.com header.s=pp1 header.b=jqE252JX; arc=pass (i=1 spf=pass spfdomain=linux.ibm.com dkim=pass dkdomain=ibm.com dmarc=pass fromdomain=linux.ibm.com); spf=pass (google.com: domain of linux-kernel+bounces-86124-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) smtp.mailfrom="linux-kernel+bounces-86124-linux.lists.archive=gmail.com@vger.kernel.org"; dmarc=pass (p=REJECT sp=NONE dis=NONE) header.from=ibm.com Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by am.mirrors.kernel.org (Postfix) with ESMTPS id EA99B1F228D0 for ; Thu, 29 Feb 2024 04:51:22 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 494CD38FA1; Thu, 29 Feb 2024 04:51:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="jqE252JX" Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BAD22374EA for ; Thu, 29 Feb 2024 04:51:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709182274; cv=none; b=R2SrJ67MDIqaEdKYzw91YqdtcdBVDsS4STyq3/7g0+E8v3e72gzfWUPYAmaFFSFwKs4nQJZyOwzWWPBO6FYvGTzK/lf+b6xs69OCbZM/hw+8Xu2aELsVMrAKzbOMEF6cofP1zKAhNGzUEZAJk1upSm/TkuTg71MZ6W4RRZIh/YY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709182274; c=relaxed/simple; bh=DMwSyXHVYtlcE39DYPUGiJ1K7z0IF3xCoLii2Sd+HCw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=RjBiXtqwQHMR6O9cAG0TE6WRfYJPRdX1aGSiWw0BMs50pnsyP81mU47JpZrDc7Kt3FswF2eyQmt3W6PfgBj525ApYqxASj8VRQmP50Yu7pHXPmBnx9hmTtYQPyVUA/JEj6e+Bqqq9X09P7yuMND8fR/wilHkjAMeA3WPKUoJP/U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=jqE252JX; arc=none smtp.client-ip=148.163.158.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Received: from pps.filterd (m0353725.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 41T3x6a0020886; Thu, 29 Feb 2024 04:50:55 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=pp1; bh=F1j6OMAur2EReyq9uj1aosLkqEbI8SlT5bNl5MURpv4=; b=jqE252JXeQsT4tL1QaG4ucsRBvP9SxjSPbEfhmz5CdrS6247PbKd3hOHjQfkVliguh+H MrOjDBbRVGWbj4oX72MIQZUcPw0ZzMkzIkd8lWiXfRjpR661WnQdL0cU8cMWjKQrYh3F ApWhsFYn9s/tLKYF5ew8OwfVa2KtGgeqzWRkLiXSbXq+eP7LHdLhh7m6I6KDZxG+CbDv K13540TgjDULwBl1F/akwd4ltPMUlvmAXd+zo7yFQdY6S/Wkem3kDh+4s2NU9d8+irHj 8aBs4SRL0fKAvFbKmANda//Xtd7MeUBTLiPcuSSGKWodSkqMqNZw2J/ZCH0xgoaFoUc4 Iw== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3wjj8p1f7c-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 29 Feb 2024 04:50:55 +0000 Received: from m0353725.ppops.net (m0353725.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 41T4m7Xa030470; Thu, 29 Feb 2024 04:50:54 GMT Received: from ppma23.wdc07v.mail.ibm.com (5d.69.3da9.ip4.static.sl-reverse.com [169.61.105.93]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3wjj8p1f5d-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 29 Feb 2024 04:50:54 +0000 Received: from pps.filterd (ppma23.wdc07v.mail.ibm.com [127.0.0.1]) by ppma23.wdc07v.mail.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 41T2mM5f008178; Thu, 29 Feb 2024 04:46:56 GMT Received: from smtprelay03.wdc07v.mail.ibm.com ([172.16.1.70]) by ppma23.wdc07v.mail.ibm.com (PPS) with ESMTPS id 3wfv9mjvfv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 29 Feb 2024 04:46:56 +0000 Received: from smtpav02.wdc07v.mail.ibm.com (smtpav02.wdc07v.mail.ibm.com [10.39.53.229]) by smtprelay03.wdc07v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 41T4krqM36831586 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 29 Feb 2024 04:46:55 GMT Received: from smtpav02.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 702CE58061; Thu, 29 Feb 2024 04:46:53 +0000 (GMT) Received: from smtpav02.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B33E55805C; Thu, 29 Feb 2024 04:46:48 +0000 (GMT) Received: from [9.109.201.126] (unknown [9.109.201.126]) by smtpav02.wdc07v.mail.ibm.com (Postfix) with ESMTP; Thu, 29 Feb 2024 04:46:48 +0000 (GMT) Message-ID: Date: Thu, 29 Feb 2024 10:16:47 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 0/2] sched/fair: Limit access to overutilized Content-Language: en-US To: Qais Yousef Cc: mingo@kernel.org, peterz@infradead.org, vincent.guittot@linaro.org, yu.c.chen@intel.com, dietmar.eggemann@arm.com, linux-kernel@vger.kernel.org, nysal@linux.ibm.com, aboorvad@linux.ibm.com, srikar@linux.vnet.ibm.com, vschneid@redhat.com, pierre.gondois@arm.com, morten.rasmussen@arm.com References: <20240228071621.602596-1-sshegde@linux.ibm.com> <20240229000817.n2bnr4kioigaqtct@airbuntu> From: Shrikanth Hegde In-Reply-To: <20240229000817.n2bnr4kioigaqtct@airbuntu> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: gdikrROokuNS7VWchLzpdurmXl9rRuZf X-Proofpoint-ORIG-GUID: bT1nYwcRrlPwGD45CyWhVpK2OEOrlEnE X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.1011,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2024-02-28_08,2024-02-27_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 phishscore=0 spamscore=0 mlxlogscore=999 impostorscore=0 malwarescore=0 adultscore=0 clxscore=1015 mlxscore=0 bulkscore=0 suspectscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2311290000 definitions=main-2402290035 On 2/29/24 5:38 AM, Qais Yousef wrote: > On 02/28/24 12:46, Shrikanth Hegde wrote: [...] >> Overutilized was added for EAS(Energy aware scheduler) to choose either >> EAS aware load balancing or regular load balance. As checked, on x86 and > > It actually toggles load balance on/off (off if !overutilized). > > misfit load balance used to be controlled by this but this was decoupled since > commit e5ed0550c04c ("sched/fair: unlink misfit task from cpu overutilized") > Ok. >> powerpc both overload and overutilized share the same cacheline in rd. >> Updating overutilized is not required for non-EAS platforms. > > Is the fact these two share the cacheline is part of the problem? From patch > 1 it seems the fact that overutlized is updated often on different cpus is the > problem? Did you try to move overutlized to different places to see if this > alternatively helps? > > The patches look fine to me. I am just trying to verify that indeed the access > to overutilzed is the problem, not something else being on the same cacheline > is accidentally being slowed down, which means the problem can resurface in the > future. > We did explicit cachealign for overload. By doing that newidle_balance goes away from perf profile. But enqueue_task_fair still remains. That because there is load-store tearing happening on overutilized field alone due to different CPUs accessing and updating it at the same time. We have also verified that rq->rd->overutilized in enqueue_task_fair path is the reason for it showing up in perf profile. >> [...] >> >> -- >> 2.39.3 >>