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=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 C1C8FC04AAF for ; Sat, 18 May 2019 22:20:09 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8A11720848 for ; Sat, 18 May 2019 22:20:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="PmN0jxYA"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=marvell.com header.i=@marvell.com header.b="ueY3kfMc"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=marvell.onmicrosoft.com header.i=@marvell.onmicrosoft.com header.b="VAX9XW5W" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8A11720848 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=marvell.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Content-ID:In-Reply-To: References:Message-ID:Date:Subject:To:From:Reply-To:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=pZy+Qa6ea8NYiaoVYYNrED+Wps1tPH858lGMdJJbGjc=; b=PmN0jxYAxZoG1E ghkdx4gKM43fptDG+jWKZf16aFhssZuG9i5X7xpwdhtFJHcPL254c0l9O6tH9anbYBKEEG6Rpxeku ycM5ZcI8n5NKU820tPuL2+ZKC7CTcomx8zM/B0btVp6fFmyC+4ZMODT7Nq37D750T5GBou2eIVItA l11R5TtC/I7fkTTWFL2zMcRE8I6DOQucEQRop9qdvs1RJIPrbcXHy86fqxVOEnQ3HMX10s3IK5FcK zGQvPF5XSqSIAXkvN+/XFYiqjOSPJtzzUH3+TkhDeXAYJGvqOHq6KVnbf/331NPiCmw96qVWx4p+n MUaJSViesUxIU9V+GRHw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hS7gQ-0007aa-Kk; Sat, 18 May 2019 22:20:02 +0000 Received: from mx0a-0016f401.pphosted.com ([67.231.148.174] helo=mx0b-0016f401.pphosted.com) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hS7gM-0007Xx-7m for linux-arm-kernel@lists.infradead.org; Sat, 18 May 2019 22:20:00 +0000 Received: from pps.filterd (m0045849.ppops.net [127.0.0.1]) by mx0a-0016f401.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x4IMGIl5019200; Sat, 18 May 2019 15:19:42 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=marvell.com; h=from : to : cc : subject : date : message-id : references : in-reply-to : content-type : content-id : content-transfer-encoding : mime-version; s=pfpt0818; bh=zPpF+E4qf5XwunWEKU9m3rXUvgiPzdsLDXnkg1vt7r8=; b=ueY3kfMc/GIZHqq94fkAMwhBwJqb2E19R4G+/iIRpMabUqDmQtpqapN/hjIPAq0RAwJJ byul15iA1LMoT9An6s4msbx9otiAJRXS0JbQsd11MAVblGZ47MEIVeXIgL1p2nnP33QU 9U6A+6yVCHOBFzA6E6QA2xPZ+ymfX9Oft2fljzT7R3dJgVs11vZxb2pgXmwq0hNY6JhE ue/RS1D8hP0kTDFdH0qxeEg2EuEIK1eqtPPA2A/il1bb1MS2DvvJ6drb751C5tPo4Fv5 uPSxqBgKo7NzyOgFenyXdke9dxSJqvoFaiws0/bYOTVL3PzydfljKDPTEuY7fo9uo0FD Kw== Received: from sc-exch01.marvell.com ([199.233.58.181]) by mx0a-0016f401.pphosted.com with ESMTP id 2sjfdna45q-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT); Sat, 18 May 2019 15:19:42 -0700 Received: from SC-EXCH01.marvell.com (10.93.176.81) by SC-EXCH01.marvell.com (10.93.176.81) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Sat, 18 May 2019 15:19:41 -0700 Received: from NAM03-DM3-obe.outbound.protection.outlook.com (104.47.41.55) by SC-EXCH01.marvell.com (10.93.176.81) with Microsoft SMTP Server (TLS) id 15.0.1367.3 via Frontend Transport; Sat, 18 May 2019 15:19:41 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=marvell.onmicrosoft.com; s=selector2-marvell-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=zPpF+E4qf5XwunWEKU9m3rXUvgiPzdsLDXnkg1vt7r8=; b=VAX9XW5WhKksGjttJML36rLWjH2YvFQOsC3Bj5iFHtlesud1ea3qxibQ/ebtKOCm8hDYzrXbelFPQodR3u6ItMKLENP1rKfGm3+woHNwPfJg9Lilbbw31cx55g+9G+xDGiPNEj3liKxlwvA5kunWzvp0kXuIdIBOQsPMs/zOhi8= Received: from CY4PR1801MB1942.namprd18.prod.outlook.com (10.171.255.33) by CY4PR1801MB2053.namprd18.prod.outlook.com (10.171.255.158) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.1900.18; Sat, 18 May 2019 22:19:39 +0000 Received: from CY4PR1801MB1942.namprd18.prod.outlook.com ([fe80::f4b5:9677:2811:41f4]) by CY4PR1801MB1942.namprd18.prod.outlook.com ([fe80::f4b5:9677:2811:41f4%7]) with mapi id 15.20.1900.010; Sat, 18 May 2019 22:19:39 +0000 From: Jayachandran Chandrasekharan Nair To: Aaro Koskinen Subject: Re: [PATCH] arm64: Improve parking of stopped CPUs Thread-Topic: [PATCH] arm64: Improve parking of stopped CPUs Thread-Index: AQHVDcfI5x/sF5wA3UeCqYbu03qmXg== Date: Sat, 18 May 2019 22:19:39 +0000 Message-ID: <20190518221929.GA6135@dc5-eodlnx05.marvell.com> References: <1485942532-2643-1-git-send-email-jnair@caviumnetworks.com> <20190516184452.GE10985@darkstar.musicnaut.iki.fi> In-Reply-To: <20190516184452.GE10985@darkstar.musicnaut.iki.fi> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-clientproxiedby: BY5PR03CA0014.namprd03.prod.outlook.com (2603:10b6:a03:1e0::24) To CY4PR1801MB1942.namprd18.prod.outlook.com (2603:10b6:910:7a::33) x-ms-exchange-messagesentrepresentingtype: 1 x-originating-ip: [199.233.59.128] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 83f5a003-0ec6-46aa-2afb-08d6dbdeeafa x-microsoft-antispam: BCL:0; PCL:0; RULEID:(2390118)(7020095)(4652040)(8989299)(4534185)(4627221)(201703031133081)(201702281549075)(8990200)(5600141)(711020)(4605104)(2017052603328)(7193020); SRVR:CY4PR1801MB2053; x-ms-traffictypediagnostic: CY4PR1801MB2053: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:6108; x-forefront-prvs: 0041D46242 x-forefront-antispam-report: SFV:NSPM; SFS:(10009020)(396003)(376002)(366004)(136003)(346002)(39850400004)(199004)(189003)(26005)(2906002)(14454004)(81166006)(476003)(54906003)(6916009)(1076003)(11346002)(86362001)(186003)(81156014)(8936002)(446003)(316002)(6512007)(68736007)(5660300002)(66066001)(33656002)(66476007)(6486002)(256004)(8676002)(14444005)(71190400001)(99286004)(25786009)(66446008)(64756008)(66556008)(53936002)(6436002)(76176011)(71200400001)(52116002)(4326008)(305945005)(7736002)(73956011)(386003)(6506007)(66946007)(229853002)(6116002)(3846002)(478600001)(486006)(6246003)(102836004); DIR:OUT; SFP:1101; SCL:1; SRVR:CY4PR1801MB2053; H:CY4PR1801MB1942.namprd18.prod.outlook.com; FPR:; SPF:None; LANG:en; PTR:InfoNoRecords; A:1; MX:1; received-spf: None (protection.outlook.com: marvell.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: SH8GMv7tfpDGO5Aiau2MrqwljDH5p/Ro1YtTXSSu2w9aH+er76cln0tP6bGdthlDniIU7+lNkqAkat9ElVFbva4tAErsHIxhpjXcJAP+yXvk/smj94ByyvaZnA7T6aXUd1q/z37AKh8Csa5si2HCEssSQmvMtWC2gnRL+GmmovW0259cs6Cof+sq1FcOdhaYPBwaYDE3/nsIDoya5AtDZpirSaQkphz+E2Q5ONq5kGruMlLiI5SCnlpv6YBIASzCMJ4jaNBx4xUWAXyL4MuN/oPr+TdE0c9JDXcBkw4Ktb/2yRJ06MvOC3m29VkSZk9jq8ACHxcRcAERAbQvHRmNbb3TS5T9jFfznEde5eoEKLI1bCHTow74OZ9FSaNhg/xAI/qiEtFVBb1I8P1VhdtxV0RA1h1dmOboIvqaQoBgP/0= Content-ID: MIME-Version: 1.0 X-MS-Exchange-CrossTenant-Network-Message-Id: 83f5a003-0ec6-46aa-2afb-08d6dbdeeafa X-MS-Exchange-CrossTenant-originalarrivaltime: 18 May 2019 22:19:39.5297 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 70e1fb47-1155-421d-87fc-2e58f638b6e0 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY4PR1801MB2053 X-OriginatorOrg: marvell.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-05-18_17:, , signatures=0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190518_151958_434234_7041416F X-CRM114-Status: GOOD ( 24.74 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Catalin Marinas , Will Deacon , Jayachandran C , "linux-arm-kernel@lists.infradead.org" , Suzuki K Poulose Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, May 16, 2019 at 09:44:53PM +0300, Aaro Koskinen wrote: > External Email > > ---------------------------------------------------------------------- > Hi, > > On Wed, Feb 01, 2017 at 09:48:52AM +0000, Jayachandran C wrote: > > The current code puts the stopped cpus in an 'yield' instruction loop. > > Using a busy loop here is unnecessary, we can use the cpu_park_loop() > > function here to do a wfi/wfe. > > > > Signed-off-by: Jayachandran C > > Looks like this patch has been forgotten? > > I have a system where CPUs need to be put in wfi/wfe for the warm reset > to work, and using cpu_park_loop() would solve this. If I remember correctly (it has been a while), in my testing I saw that the wfi does not block after a while since interrupts are pending. Most likely that timer interrupts will still be enabled. We might need some code to reset/disable the GIC interface for the CPU before parking. > > arch/arm64/kernel/smp.c | 3 +-- > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c > > index cbaab44..0691d2f 100644 > > --- a/arch/arm64/kernel/smp.c > > +++ b/arch/arm64/kernel/smp.c > > @@ -829,8 +829,7 @@ static void ipi_cpu_stop(unsigned int cpu) > > > > local_irq_disable(); > > > > - while (1) > > - cpu_relax(); > > + cpu_park_loop(); > > } > > > > /* JC _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel