From patchwork Wed Jun 10 21:05:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tom Hromatka X-Patchwork-Id: 11598921 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9BC4A913 for ; Wed, 10 Jun 2020 21:08:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8112D20760 for ; Wed, 10 Jun 2020 21:08:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="l00YqhZu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726317AbgFJVIC (ORCPT ); Wed, 10 Jun 2020 17:08:02 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:59316 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726134AbgFJVIC (ORCPT ); Wed, 10 Jun 2020 17:08:02 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 05AL6ZKo049476; Wed, 10 Jun 2020 21:07:52 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=corp-2020-01-29; bh=D8dZBcbd0rS3Mfv7fJRsU05nZ7ZNUJshc+qX8byxghM=; b=l00YqhZu6VQKiuY2NcMYYhH2xKq6Xu3lotQq2J9LMSOioRLNXq/0xMAMtAzNda/ERupI AJmQSL8zDZ2mcKUUymKxwlxJmc9AJzVjlOMkUndwHqAq7TfVu05/+vs8F8c6X5BgLz8U 9DkPoZ6HNqAn5LYJQUXlDCP/CGRlK8UywXe+S5nRw5Sm5JUttK/3Vq5tkEwO9+dW5JDg crXMz5euEmReQ0XtvMRB8ET3voelroEqNITATRrCQD+C9MKKClcEqumfJWsz/gpH7csm j+aL2CYKrjkDllLHyf2j3D3TvGZFXc4zo/hOBIwcTuElzOnvrK5c3Qexs2m1WP1Paqus /g== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by userp2130.oracle.com with ESMTP id 31g2jrcma8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 10 Jun 2020 21:07:52 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 05AKiSOm132390; Wed, 10 Jun 2020 21:05:51 GMT Received: from pps.reinject (localhost [127.0.0.1]) by userp3020.oracle.com with ESMTP id 31gmwtve3t-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 10 Jun 2020 21:05:51 +0000 Received: from userp3020.oracle.com (userp3020.oracle.com [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 05AL5o8c021995; Wed, 10 Jun 2020 21:05:51 GMT Received: from localhost.localdomain (dhcp-10-65-148-96.vpn.oracle.com [10.65.148.96]) by userp3020.oracle.com with ESMTP id 31gmwtve2s-2; Wed, 10 Jun 2020 21:05:51 +0000 From: Tom Hromatka To: tom.hromatka@oracle.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: fweisbec@gmail.com, tglx@linutronix.de, mingo@kernel.org, adobriyan@gmail.com Subject: [PATCH 1/2] tick-sched: Do not clear the iowait and idle times Date: Wed, 10 Jun 2020 15:05:48 -0600 Message-Id: <20200610210549.61193-2-tom.hromatka@oracle.com> X-Mailer: git-send-email 2.25.3 In-Reply-To: <20200610210549.61193-1-tom.hromatka@oracle.com> References: <20200610210549.61193-1-tom.hromatka@oracle.com> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9648 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 impostorscore=0 cotscore=-2147483648 priorityscore=1501 spamscore=0 suspectscore=0 lowpriorityscore=0 bulkscore=0 mlxlogscore=999 malwarescore=0 mlxscore=0 phishscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006100155 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org A customer reported that when a cpu goes offline and then comes back online, the overall cpu idle and iowait data in /proc/stat decreases. This is wreaking havoc with their cpu usage calculations. Prior to this patch: user nice system idle iowait cpu 1390748 636 209444 9802206 19598 cpu1 178384 75 24545 1392450 3025 take cpu1 offline and bring it back online user nice system idle iowait cpu 1391209 636 209682 8453440 16595 cpu1 178440 75 24572 627 0 To prevent this, do not clear the idle and iowait times for the cpu that has come back online. With this patch: user nice system idle iowait cpu 129913 17 17590 166512 704 cpu1 15916 3 2395 20989 47 take cpu1 offline and bring it back online user nice system idle iowait cpu 130089 17 17686 184625 711 cpu1 15942 3 2401 23088 47 Signed-off-by: Tom Hromatka --- kernel/time/tick-sched.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 3e2dc9b8858c..8103bad7bbd6 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -1375,13 +1375,22 @@ void tick_setup_sched_timer(void) void tick_cancel_sched_timer(int cpu) { struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); + ktime_t idle_sleeptime, iowait_sleeptime; # ifdef CONFIG_HIGH_RES_TIMERS if (ts->sched_timer.base) hrtimer_cancel(&ts->sched_timer); # endif + /* save off and restore the idle_sleeptime and the iowait_sleeptime + * to avoid discontinuities and ensure that they are monotonically + * increasing + */ + idle_sleeptime = ts->idle_sleeptime; + iowait_sleeptime = ts->iowait_sleeptime; memset(ts, 0, sizeof(*ts)); + ts->idle_sleeptime = idle_sleeptime; + ts->iowait_sleeptime = iowait_sleeptime; } #endif