From mboxrd@z Thu Jan 1 00:00:00 1970 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 E1E943D972 for ; Wed, 20 Dec 2023 14:49:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.vnet.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.vnet.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="ClvpklYP" Received: from pps.filterd (m0360072.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3BKEjJ1N010381; Wed, 20 Dec 2023 14:48:51 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=9ZJ+mGAq5RlbQCkh+6A8mvZK3kZnxP0yjFw34mQOsgo=; b=ClvpklYPrsbtXgIjCG8zBR/Zi/wXo9MY9kAU9zGLMeRMRCxMzktOKxaNcfcgM64xBKsT yPFxR1iJeVW9vvJ6zsnkymi9LVb4KHZXihDEKmMY72ZkovmqYuJsFwGKv3lgU3GlWcuf ADoIzbkIDNY1hTmNuPSaJ11HoTQ/sBeTzh/VNJUqp/JX9Q8j/3PmnqHvNxjv9/h2rrv6 5jDhnSdtUBTgbPUJc7EihUSX71mxGdGKtcyb777IstdCmpZGZX3xuQmNAgWD8CCPMxUd lIQblw3oPdpymdgAEHVrHEgJvZmjCHozOetgcN10K32YaGOadQLTmyzZkWjbIUPxkajw YA== Received: from ppma13.dal12v.mail.ibm.com (dd.9e.1632.ip4.static.sl-reverse.com [50.22.158.221]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3v41mq98sr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 20 Dec 2023 14:48:50 +0000 Received: from pps.filterd (ppma13.dal12v.mail.ibm.com [127.0.0.1]) by ppma13.dal12v.mail.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 3BKCS3lC027076; Wed, 20 Dec 2023 14:48:49 GMT Received: from smtprelay03.wdc07v.mail.ibm.com ([172.16.1.70]) by ppma13.dal12v.mail.ibm.com (PPS) with ESMTPS id 3v1rek6mpb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 20 Dec 2023 14:48:49 +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 3BKEmm868258222 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 Dec 2023 14:48:48 GMT Received: from smtpav02.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A8D6758058; Wed, 20 Dec 2023 14:48:48 +0000 (GMT) Received: from smtpav02.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 976E458059; Wed, 20 Dec 2023 14:48:45 +0000 (GMT) Received: from [9.43.114.58] (unknown [9.43.114.58]) by smtpav02.wdc07v.mail.ibm.com (Postfix) with ESMTP; Wed, 20 Dec 2023 14:48:45 +0000 (GMT) Message-ID: <85230ed0-26a0-4f08-aab0-f0a6ce03abe8@linux.vnet.ibm.com> Date: Wed, 20 Dec 2023 20:18:44 +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] sched: move access of avg_rt and avg_dl into existing helper functions To: Vincent Guittot Cc: mingo@kernel.org, peterz@infradead.org, dietmar.eggemann@arm.com, linux-kernel@vger.kernel.org, srikar@linux.vnet.ibm.com, yu.c.chen@intel.com, tim.c.chen@linux.intel.com References: <20231220065522.351915-1-sshegde@linux.vnet.ibm.com> Content-Language: en-US From: Shrikanth Hegde In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: y_RsWzR6zoHEMipnPktbzQeJqAzKZZ1w X-Proofpoint-GUID: y_RsWzR6zoHEMipnPktbzQeJqAzKZZ1w X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.997,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-12-20_08,2023-12-20_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 adultscore=0 mlxscore=0 lowpriorityscore=0 malwarescore=0 priorityscore=1501 bulkscore=0 impostorscore=0 spamscore=0 phishscore=0 suspectscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2311290000 definitions=main-2312200106 On 12/20/23 7:29 PM, Vincent Guittot wrote: Hi Vincent, thanks for taking a look. > On Wed, 20 Dec 2023 at 07:55, Shrikanth Hegde > wrote: >> >> This is a minor code simplification. There are helper functions called >> cpu_util_dl and cpu_util_rt which gives the average utilization of DL >> and RT respectively. But there are few places in code where these >> variables are used directly. >> >> Instead use the helper function so that code becomes simpler and easy to >> maintain later on. >> >> Signed-off-by: Shrikanth Hegde >> --- >> kernel/sched/fair.c | 12 +++++------- >> 1 file changed, 5 insertions(+), 7 deletions(-) >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index bcea3d55d95d..02631060ca7e 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -9212,19 +9212,17 @@ static inline bool cfs_rq_has_blocked(struct cfs_rq *cfs_rq) >> >> static inline bool others_have_blocked(struct rq *rq) >> { >> - if (READ_ONCE(rq->avg_rt.util_avg)) >> + if (cpu_util_rt(rq)) >> return true; >> >> - if (READ_ONCE(rq->avg_dl.util_avg)) >> + if (cpu_util_dl(rq)) >> return true; >> >> if (thermal_load_avg(rq)) >> return true; >> >> -#ifdef CONFIG_HAVE_SCHED_AVG_IRQ >> - if (READ_ONCE(rq->avg_irq.util_avg)) >> + if (cpu_util_irq(rq)) > > cpu_util_irq doesn't call READ_ONCE() > I see. Actually it would be right if cpu_util_irq does call READ_ONCE no? Sorry i havent yet understood the memory barriers in details. Please correct me if i am wrong here, since ___update_load_avg(&rq->avg_irq, 1) does use WRITE_ONCE and reading out this value using cpu_util_irq on a different CPU should use READ_ONCE no? > >> return true; >> -#endif >> >> return false; >> } >> @@ -9481,8 +9479,8 @@ static unsigned long scale_rt_capacity(int cpu) >> * avg_thermal.load_avg tracks thermal pressure and the weighted >> * average uses the actual delta max capacity(load). >> */ >> - used = READ_ONCE(rq->avg_rt.util_avg); >> - used += READ_ONCE(rq->avg_dl.util_avg); >> + used = cpu_util_rt(rq); >> + used += cpu_util_dl(rq); >> used += thermal_load_avg(rq); >> >> if (unlikely(used >= max)) >> -- >> 2.39.3 >>