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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 BF4ACC43331 for ; Fri, 6 Sep 2019 17:51:02 +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 98649207FC for ; Fri, 6 Sep 2019 17:51:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="svXl4cBN"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=microsoft.com header.i=@microsoft.com header.b="OA3XQkN+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 98649207FC Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=microsoft.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=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:In-Reply-To:References: Message-ID:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=9AXqw6zXyhy9BZ5D3J0uzu6KO8p7hsdTqUUAEh08Poo=; b=svXl4cBNw/G+fJ LG5pPtXa5pOjeInMaJu/QAqCGCq/G3oklXpRpfVBW2qqsLcJqULtI6QMUmybfa/Dw1Vbt7J7Um28Q ZXH2zhJ9Cttx88t19tQn2+jaSefgY1j6i6Bs1XqNs/RR0mdKtQU8blk/Lqdfz5O2mv15kg2eigvY5 Tb32Km5cTaBMvZLPZUiD7QEjk7zUCMWpbvje51ofk17Y0gZ7izrjCawFKVYPLzkLynXBez+a92JYF Vlz2vLgRzcFtCqntGZR6K0D0jWiz1S95jLJz/bUEPbrRqR2l4ifjss9/T5hnlYqNMwZV6X7euHBaz veWw5hLuNEkk7ipWdVpw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i6INt-00033o-GV; Fri, 06 Sep 2019 17:50:57 +0000 Received: from mail-dm3nam05on0705.outbound.protection.outlook.com ([2a01:111:f400:fe51::705] helo=NAM05-DM3-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1i6INp-00032u-VR for linux-nvme@lists.infradead.org; Fri, 06 Sep 2019 17:50:56 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=IuhA47oMcbL0yGVsdC5+jdIH5xvjOgbH+9VOZOyN9eYyN5O78STFwBxrdKMwFuz5qkPyObeMbBep/049aPfsCQfCJg3cBbmtLVZl2xlfF1qwmo60/gD01FDZRs0986ie1NwgHs1e238b57uElMWmXIkf/9nCRYX1qOZ8jSSq4NhYW/lcpgJwsysy8lY28wQZ3WOnUtPva+GQnNI+4xUqHqPK4yBVoEngkfMC42qZlyxPw9IoS+DvPEn9Dt02ZMbr1SJQvFlCZee3MJH+qnC0+1IxsyVpaqeosGq+fjJePjpEE30oouTQhFu87o31W+e9XQRLoNIBBDEGQ8eJgC/ivg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=zlTiyqMp1eW1Jvk9hPLcbfzRcnwfTnZVtSMpBc8vs0c=; b=TYKvkxg+fqmmo08KUChacl7i0zGUqdf/RsoOEuxK/dSegwE5Ru1aRmxve84AuyLHW+uDJwWG0fQAi48H09gqs/j85TZtfNB2++MpjzMge9GRxqCJJ8sGAq0L/khVZh69Ub42vN4nWgZ959cLeP22p8W923MQUiZdQE05BX5TxykPfq+D7bIlUdbDh35Hb+FjPu9nlVTRmYGMuzSM3MfoUATVghUMFbCpycGsCJ65lHtNL7br2v5ylM0q9Lm7aBJea33Y5g/w1fUtXelGOPE8ZH6/AzUDDa1hSp0NckuNp7qUx41P9bZP16K85F09hSzIJUT9J+3pCegCaPHl1px1zA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=microsoft.com; dmarc=pass action=none header.from=microsoft.com; dkim=pass header.d=microsoft.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=zlTiyqMp1eW1Jvk9hPLcbfzRcnwfTnZVtSMpBc8vs0c=; b=OA3XQkN+Ybym91RGctAZDuS1zuGsnA++7iD/nex8J3gB9Yyz6ylXJiNUKSrE3cuN034C/D7xIH82Ola0sy4nYDjI7qiuiUuSbl5wDbrztEToSyssqaYoBwuSX4SIhHyLocfFqM/yOd2XsGiKHPw7h7wZ4FeZvjLGTDgV/eGegO4= Received: from CY4PR21MB0741.namprd21.prod.outlook.com (10.173.189.7) by CY4PR21MB0277.namprd21.prod.outlook.com (10.173.193.143) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2263.9; Fri, 6 Sep 2019 17:50:50 +0000 Received: from CY4PR21MB0741.namprd21.prod.outlook.com ([fe80::5caa:ae40:7c3a:4b1d]) by CY4PR21MB0741.namprd21.prod.outlook.com ([fe80::5caa:ae40:7c3a:4b1d%5]) with mapi id 15.20.2263.005; Fri, 6 Sep 2019 17:50:50 +0000 From: Long Li To: Keith Busch , Ming Lei Subject: RE: [PATCH 1/4] softirq: implement IRQ flood detection mechanism Thread-Topic: [PATCH 1/4] softirq: implement IRQ flood detection mechanism Thread-Index: AQHVXLUAoNqN0R8TLUadmsLcmKb6xacPEcMAgACKtgCAAAMjAIAAyEgAgAAEnwCAAClMgIAABJWAgAi79gCAACnHgIAACOEAgAACjoCAAA16gIAABfMAgAIuJgCAAAa1AIABBRqAgAAZZYCAAP6SgIAA0bgAgAA1zGA= Date: Fri, 6 Sep 2019 17:50:49 +0000 Message-ID: References: <299fb6b5-d414-2e71-1dd2-9d6e34ee1c79@linaro.org> <20190903063125.GA21022@ming.t460p> <6b88719c-782a-4a63-db9f-bf62734a7874@linaro.org> <20190903072848.GA22170@ming.t460p> <6f3b6557-1767-8c80-f786-1ea667179b39@acm.org> <2a8bd278-5384-d82f-c09b-4fce236d2d95@linaro.org> <20190905090617.GB4432@ming.t460p> <6a36ccc7-24cd-1d92-fef1-2c5e0f798c36@linaro.org> <20190906014819.GB27116@ming.t460p> <20190906141858.GA3953@localhost.localdomain> In-Reply-To: <20190906141858.GA3953@localhost.localdomain> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: spf=none (sender IP is ) smtp.mailfrom=longli@microsoft.com; x-originating-ip: [2001:4898:80e8:f:edde:db5c:c6fe:798] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 6cad81fc-e79e-4e2e-37f7-08d732f2c13e x-ms-office365-filtering-ht: Tenant x-microsoft-antispam: BCL:0; PCL:0; RULEID:(2390118)(7020095)(4652040)(8989299)(5600166)(711020)(4605104)(1401327)(4618075)(4534185)(4627221)(201703031133081)(201702281549075)(8990200)(2017052603328)(7193020); SRVR:CY4PR21MB0277; x-ms-traffictypediagnostic: CY4PR21MB0277: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:8273; x-forefront-prvs: 0152EBA40F x-forefront-antispam-report: SFV:NSPM; SFS:(10019020)(4636009)(396003)(136003)(376002)(346002)(366004)(39860400002)(199004)(189003)(6506007)(66476007)(66946007)(33656002)(2906002)(76116006)(52536014)(10290500003)(25786009)(22452003)(66556008)(64756008)(66446008)(71190400001)(478600001)(86362001)(81166006)(81156014)(8936002)(7696005)(102836004)(6116002)(5660300002)(7736002)(71200400001)(10090500001)(14454004)(229853002)(256004)(99286004)(8676002)(486006)(74316002)(46003)(55016002)(9686003)(6246003)(186003)(53936002)(4326008)(476003)(11346002)(6436002)(7416002)(8990500004)(110136005)(54906003)(76176011)(305945005)(316002)(446003); DIR:OUT; SFP:1102; SCL:1; SRVR:CY4PR21MB0277; H:CY4PR21MB0741.namprd21.prod.outlook.com; FPR:; SPF:None; LANG:en; PTR:InfoNoRecords; A:1; MX:1; received-spf: None (protection.outlook.com: microsoft.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: Df7TGTtjiuRmz+khaLZPymc8OAB3W/2kwy1SIHIwlSlK/n/0ZGv/WgIQoC9713Qn2tpMUxUddE5YQVWd9dLJF0NYiV84MT9rmhP53XBES5lx4lSBOn7RTVZaJ1iAP4COOsa1Hu+cWifcbO9HtF/STUYj8pA+eDUjA7BpgLn1xTQ/8bpSpd3r6aE2XqthuX/DXzYumcFATGsJIKAxk6VGna8iNAPLZTME9nJOcHgBnk0hmfUY1kXyNg51RxmTlRmh/KT5Lm5BsmtoyNzQxdoUz1m+2AfPQ4zgIb1nDY0piaHbJpWaxCdQcg48kCOXjO7nLQye0xqag6gInRh0lc1gl6xEtPk6Ky2NcDaADpw+Hg5KIB3kdj08vNraK/TKOIF1F3YZXNVEimCgyiHWWh2lFsM7UlO36jdnXW4y+i+dS24= x-ms-exchange-transport-forked: True MIME-Version: 1.0 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-Network-Message-Id: 6cad81fc-e79e-4e2e-37f7-08d732f2c13e X-MS-Exchange-CrossTenant-originalarrivaltime: 06 Sep 2019 17:50:50.0409 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: uzBb05ePqfOJjXT9c7vEJ2P1BGBq7awr69T0vI0PKsvdf8heD9OeJ9J7fJCjuwlskXiYMicJOn3wvs2vfcjZlw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY4PR21MB0277 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190906_105054_176728_3C25EEAF X-CRM114-Status: GOOD ( 11.78 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jens Axboe , Hannes Reinecke , John Garry , Bart Van Assche , "linux-scsi@vger.kernel.org" , Peter Zijlstra , Daniel Lezcano , LKML , "linux-nvme@lists.infradead.org" , Keith Busch , Ingo Molnar , Thomas Gleixner , Christoph Hellwig , Sagi Grimberg Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org >Subject: Re: [PATCH 1/4] softirq: implement IRQ flood detection mechanism > >On Fri, Sep 06, 2019 at 09:48:21AM +0800, Ming Lei wrote: >> When one IRQ flood happens on one CPU: >> >> 1) softirq handling on this CPU can't make progress >> >> 2) kernel thread bound to this CPU can't make progress >> >> For example, network may require softirq to xmit packets, or another >> irq thread for handling keyboards/mice or whatever, or rcu_sched may >> depend on that CPU for making progress, then the irq flood stalls the >> whole system. >> >> > >> > AFAIU, there are fast medium where the responses to requests are >> > faster than the time to process them, right? >> >> Usually medium may not be faster than CPU, now we are talking about >> interrupts, which can be originated from lots of devices concurrently, >> for example, in Long Li'test, there are 8 NVMe drives involved. > >Why are all 8 nvmes sharing the same CPU for interrupt handling? >Shouldn't matrix_find_best_cpu_managed() handle selecting the least used >CPU from the cpumask for the effective interrupt handling? The tests run on 10 NVMe disks on a system of 80 CPUs. Each NVMe disk has 32 hardware queues. It seems matrix_find_best_cpu_managed() has done its job, but we may still have CPUs that service several hardware queues mapped from other issuing CPUs. Another thing to consider is that there may be other managed interrupts on the system, so NVMe interrupts may not end up evenly distributed on such a system. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme