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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 6E3BBECE564 for ; Wed, 19 Sep 2018 15:58:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EEE722150B for ; Wed, 19 Sep 2018 15:58:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=virtuozzo.com header.i=@virtuozzo.com header.b="YzdzGboO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EEE722150B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=virtuozzo.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732668AbeISVh0 (ORCPT ); Wed, 19 Sep 2018 17:37:26 -0400 Received: from mail-eopbgr10118.outbound.protection.outlook.com ([40.107.1.118]:21584 "EHLO EUR02-HE1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732492AbeISVh0 (ORCPT ); Wed, 19 Sep 2018 17:37:26 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=virtuozzo.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=AiOF7ixpQm/r73fCn/deRNrbOtx1l/vk8tHNn3Ge9kc=; b=YzdzGboOTFnkjKnyyH/XOcNHPi7K9WdoFseXGlOUkRvM6GXd/2I2NXlYgtucbffzmn1zD6Gu2DDHUFx4ixnEAN/JhWc8TmRrva/zIqv0EWEfdIyFyVXvLIAQWRXbjCsh0vymjPyM6gXpLkZze/KJIKu+mSweb9r+2AKyOx/PJiE= Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=ktkhai@virtuozzo.com; Received: from [172.16.25.169] (185.231.240.5) by DB6PR0801MB2021.eurprd08.prod.outlook.com (2603:10a6:4:76::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.1143.17; Wed, 19 Sep 2018 15:58:46 +0000 Subject: Re: [RFC] net;sched: Try to find idle cpu for RPS to handle packets To: Eric Dumazet Cc: Peter Zijlstra , David Miller , Daniel Borkmann , tom@quantonium.net, netdev , LKML References: <153736009982.24033.13696245431713246950.stgit@localhost.localdomain> <2fdf2bd7-1cc4-a1e1-15c2-e2badfcd4d59@virtuozzo.com> From: Kirill Tkhai Message-ID: <84d38f11-2133-9d34-e468-d2ef16715f49@virtuozzo.com> Date: Wed, 19 Sep 2018 18:58:44 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [185.231.240.5] X-ClientProxiedBy: AM5PR0102CA0036.eurprd01.prod.exchangelabs.com (2603:10a6:206::49) To DB6PR0801MB2021.eurprd08.prod.outlook.com (2603:10a6:4:76::14) X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 379f37ea-68ba-41a2-a50e-08d61e48c8d7 X-Microsoft-Antispam: BCL:0;PCL:0;RULEID:(7020095)(4652040)(8989299)(4534165)(4627221)(201703031133081)(201702281549075)(8990200)(5600074)(711020)(2017052603328)(7153060)(7193020);SRVR:DB6PR0801MB2021; X-Microsoft-Exchange-Diagnostics: 1;DB6PR0801MB2021;3:P2S+0Aixxh2RTBE6jHg7U0Wf60npqlUHRyyiTDRnUaeicowl3I+ESjKQh+65gqLnHIaXMcQpGBzQpH1ggAEN1HzuU5hUp+LXxF+sYeFtYHk6h46FNVsJTSbqUItnnXAtSqxTZ+fbp2GtXU5+Xca5TE5TchcLZX4om4z7E/3Ifw9w75vjoVHofbv9WZsK3rctWolOS5d/62qXaUyRAQokT1mZcCQD4WnJ4T55we5KRQMceGFs0fWRvPjqcWCPkQ6R;25:cURfdq6kBRZDHmq7mHMVGxb4v2fJa5VpE+pMRWcy45ALFvmSRH1MS8kyBcPeBDGSIVmWohyCJexAfO25MhO6YaDIKMG0kxWPo+tmfycIy/hBxwCDypKrYbtN356hKA+wNwR+1xxAf91trHerKcDujo85LiETT3PIZqvPcsJUrfB2KsORDvKX0WZI0+QpoPpOJ9hHlXbmoDTPcyADy6Sc+xzIH3GPtEdv6AY1pLxBfVAzIkm/HtegSmK/yaBZhNUAsZPl81lG7ILcnE12zEn6FygFzhQtnaBxNEY7UGSQZbdQYxjj3qCaF7X6oFbRzoUzOgMOOmkt1Kr4LrDiedlG5Q==;31:j+kdRxs4d1QvmYsYsaTjMgf5q6vFliGiaMdZUbUnRe9bkLpte8oEGLJt4cLmNUDFnT90WKNWk1WiBxUF+2ra/uKtevmmTszOEQoQGi+sj2Ywowa2FlfhAqBqMSJHclI7fjEQ7MTslXCE7g+gbD6kp1Ah0EjtqCypVXle6+cLVdFiW0FpOaOJtrF7rPE7Zumw3Z6rEPdjlPn3KYF0LLbke/fjz8/ra7jSi9l1kGe+h1g= X-MS-TrafficTypeDiagnostic: DB6PR0801MB2021: X-Microsoft-Exchange-Diagnostics: 1;DB6PR0801MB2021;20:k7EyjsZbEjN1ATT7Grxcf79R1VujXdrnRFkM1SxQYvZ7lo6y0vXMrrGUGnK39i0c5eZt8PF5paUjTUhxodxYRu3vo/42Fl2b1cVJlus3ys1MU3jDEERX4NiUV+ZZUQCTuFiascFuODnWf/k1OGbhVsVt4HJWEFb69/6QXCnUk18Z06lbsnzxCxI9lEFMOpIIN+CaEJEq0rnVcpMsOVj440/HFx+poWQzNUENbiz7iSTKY66fxKeuBm/qVqpGHkCSxxOCzjAivZPxJOJs+tsAG4sUv5BYnRBe8KObHdvG3YpXYTcfYew9zaspNYwZ0/ynzjfNRSyAI37JUhWOCFg9dfYJjxJ0bnOnxoysyBYnbfSXlS7AVv4hSJ3mbVM2zHkRO0HFIzd1Ehu5q0gclXIrbQLxnqHX70XxbMxzYLcVur9fTEIE0SkND9sFHld4oO91xUML8r/MMdvNYwSr5JYjMmQ5GnHWvIa3gqFxZqsTZykUckigsb+K703vtFDhSUQ9;4:TDpdakxZUg5uNjoIPKWKbcJci6o4Z9n5uefhoLCxaZ0iWpknXHFEFWHUu4TdFGlHTfhSGvY3HEnTxCmI5WigOjr1C53xaheYVwZQuTnZMPr2PM2+Q0wOtFSpjcYoAOpiWdv3ZI0WER5DMqOPTb0K9sVyPKxNh0GyL0TfqTD3ttoclSwlReUUJ0utPsWmXoO+a5IN+Eo4i2FIbwrrotM/Lv+JGZHn3zT3BhEDCUFS6dtIDzq1uSs9tNsutR+3MpzsDbTBAUzacIiu1KgjEAUFtUZBDoeSGhj6ja6EDDxWhWuPjf7XorGBAMOFhVPLBBrwx7ib7oy7ioyxn09LOHIQM/K6EjMZAVQRtmTW1FXmU9I= X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:(209352067349851)(269456686620040); X-MS-Exchange-SenderADCheck: 1 X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(6040522)(2401047)(8121501046)(5005006)(3002001)(10201501046)(93006095)(93001095)(3231355)(944501410)(52105095)(149027)(150027)(6041310)(20161123562045)(201703131423095)(201702281528075)(20161123555045)(201703061421075)(201703061406153)(20161123558120)(20161123564045)(20161123560045)(201708071742011)(7699050);SRVR:DB6PR0801MB2021;BCL:0;PCL:0;RULEID:;SRVR:DB6PR0801MB2021; X-Forefront-PRVS: 0800C0C167 X-Forefront-Antispam-Report: SFV:NSPM;SFS:(10019020)(6049001)(396003)(366004)(39850400004)(346002)(376002)(136003)(199004)(189003)(64126003)(4326008)(23676004)(8676002)(47776003)(16576012)(58126008)(54906003)(93886005)(50466002)(6486002)(77096007)(26005)(65826007)(3846002)(305945005)(25786009)(5660300001)(956004)(229853002)(52116002)(52146003)(53546011)(386003)(6246003)(446003)(6116002)(2486003)(11346002)(316002)(2616005)(7736002)(81166006)(486006)(68736007)(105586002)(76176011)(5024004)(66066001)(86362001)(186003)(65806001)(31696002)(53936002)(97736004)(36756003)(31686004)(16526019)(2906002)(65956001)(478600001)(8936002)(81156014)(230700001)(106356001)(6916009)(476003)(37363001);DIR:OUT;SFP:1102;SCL:1;SRVR:DB6PR0801MB2021;H:[172.16.25.169];FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;A:1;MX:1; Received-SPF: None (protection.outlook.com: virtuozzo.com does not designate permitted sender hosts) X-Microsoft-Exchange-Diagnostics: =?utf-8?B?MTtEQjZQUjA4MDFNQjIwMjE7MjM6WW9xaXRFVnNzWE9CaWlDL3VSa2tCSks5?= =?utf-8?B?TjB6ck5ncHIzKzN0SXhwVUVUekdwQjQyZWttMFVIMjdUeWZTNGp0YjdOUitl?= =?utf-8?B?UU80LzNsV3A0L1BhMFdaWkZnc0RDWktXdFE1dlQydjBUVFJpUmZ6Uit1NGpU?= =?utf-8?B?R2hYTlJvOHhnQ3hBQVpsYWVRMytNbEhDOXZQWjc1eTdhQXYrb2RnZFRyaU92?= =?utf-8?B?WFc5dXNuRHl2aEloMUFBeDlSRmR6bG1mcm1za1UyZUpWQ3ZlNVduZzZkRVox?= =?utf-8?B?YmthUzE5Z0h5T0w3b25wRDBzdmJhM0RwcDQ2RlAyRStES1NtTzIyVWtHQjdC?= =?utf-8?B?MWQ5MEFsOTBxazQyQkpIODRMWjY5LzZBVW4wUjlaaFJBL3FSWUw0YlM1WE1z?= =?utf-8?B?MlR5citxYnQvNy9xblpUVmd0clloVnluQ2xYd0ZqZEV1MmJFVE05VjluM1lU?= =?utf-8?B?R1lGWUpZcUNjOFZjaHF2ajk1WFhnUFlHNC9ibUttS3RxZEt0TDV0U0k2QUs1?= =?utf-8?B?cGgweWZIeXZNRUZQWGNxNTNXeEx1Y1MvUGdzaVZxcE52TWkvSktZSS9oTnJa?= =?utf-8?B?WkVLcFZTNjVYcUFxaHorT09aQWI0Q1RzbjFKZG1ZblQ3R1FuMXdSQVJISVBh?= =?utf-8?B?VDVqdmhyblFpRWdpNGFoYk5vWTh4aHc2MlloNTNtK1UvZlhJU21CdGt6Y1lY?= =?utf-8?B?VDFZTWw3K3FUYVY5WGV1STdJUDFlb3JXbnBPd3RHMWttRFNUVVhreE1aUEZC?= =?utf-8?B?S2JGWUNKT0EyYzVSaHd0cUs2aVRwNTZEdEtKb05LUzJnVUJxd0gvZUdYMW9I?= =?utf-8?B?dFhQSHdrK2N1TXVldlNZaHNGaVlBTHpmZ2VsL0RHN2pEdjdLdTZXbXgyL2xy?= =?utf-8?B?MjZySDV4UEFNYXRTTjdXcllacmhmdjJjQ282Q0hzTG5pQ3pKcjVTNTBHR0VP?= =?utf-8?B?b05hb011cHZHVC8vcHRZVldGRFVaR3dmbUUzMVpmMjJQakhrZno4NU53Tm9H?= =?utf-8?B?eWJJVU12eUFrczdveVptZEtCR28rOTh1b0M1aDFjT1k3OGNnUWdyNzQzc2hj?= =?utf-8?B?bUtnYjVRamwzZGhzMzNKZzUzeFU3Ti9DMG13bmYzZkcvSEdaNW9oQ255L0dt?= =?utf-8?B?aW5ESG9yY0ZmMUxjK0ZjcmllYWVGY2l5alc5TVN3NHN3ZUVsOC9UZzZwMUZR?= =?utf-8?B?eS8ycVVjTUdwNG96OXhUVWNnckFDL1VwTXlFS3J4c0xrZUVNSGFIMGlEaEZS?= =?utf-8?B?L2tXcUNMWXkyRHhpcFE4YzdLNDFEamttK0ZkcnQxLzR5NUZvVVd5WDY3UjR6?= =?utf-8?B?UG9YYlc2UkNHRC9zdFJ6NlhHYnQxdzZ0d0tGVFk4RWowK1N1Zjljd0I5Mnkx?= =?utf-8?B?b3l5cTY3eUdKcTYvcEVvYXZGcWo0cnU3ODlndWk5SHVlcC9oeWxSdjFPZlN6?= =?utf-8?B?Rzh0SWJVSlFWVnBrS28wbHRuV2RHOWo1VXdGbVlBVU1vNTREaTlzcTJoSlFj?= =?utf-8?B?NHkxNHFiRU5RN1hsNkFOKzA0MjlNb29vY0VWTjlVWnQwSEJ3bGtuM0h5alVi?= =?utf-8?B?ZEx1T1BlY0prMXpJbGNkT1JUZ201eHVtU1ZIL0ErWGp2cytzY1A5YTZjRkJk?= =?utf-8?B?VlFlSnA1K084eFVIcWdwSjVOdUlVbnVLVHJTUkNWa0xaMFE1MnpWajRkVVBO?= =?utf-8?B?aGNwM0VZbjVhUEl6bG42TjZsSDVQV2VYS0d1KzNqd0hodGxHUjl2VjlybTBh?= =?utf-8?B?TGZhZGk2Q3pCNUI3WUU2akRLeitvaEdWM2cvdUdZL1A4S3lXRlJhZE1VaUFG?= =?utf-8?B?bE5Obm5RYkx0YklzQmhTMDB4YWJGbzJzWGJLLzlvTWFiYW9abWZDcUU1Z0FJ?= =?utf-8?B?ZWlaTEhEaUpzRGdCTU1XS3hSRUg4Nkk0ZzloYzZjeVJzaUJCMitjM3VDczB1?= =?utf-8?B?TnBhMys3Y2xEdzcrSnpPR2RWV0hrd0RmOWozMHhqSUNTZHV5RUJxVTd6ek5T?= =?utf-8?Q?98T4Ob50?= X-Microsoft-Antispam-Message-Info: DV4lCZTGwMzIsIYrcSBOqLY5IQI4OqPiGMPh368xNr7sb1SlI6CI47iAZ0yR0KXU7qYiNvCZoHHDJoOH6/TVQHCVog6gVMnMDtAxa+SMvO22O/lgv8gV2hs3tDRSTZNAIrFwEaZgiC25G6UL2BaWWhpYdSTysIFFbmwhIUkgSzw1IXgSSjF0u3AbXHH3zGNfb1uX4fTlYZ3o7yyuClpQQDgvngzt/7U4yqIfCGtJm0ATzqHB5J0qWMlckdJJ+z0+heeellvqJtWYcgqGJJITFUbK08osp3kAeildxFF/R8UHBeoli9Sxl3uzhYMEuEeEvFvPlevxdTo2TH2DsJnOkIpBbvsuibsHZ2qMQENbtVQ= X-Microsoft-Exchange-Diagnostics: 1;DB6PR0801MB2021;6:bTjcU1FCD/aBn6jUxBSWFnAnT8Le/nuY7POTcwVN6VpKZos70VGP/aRuHzo4mvEM2rUhG5ikmpDZu24iZNVBCV+MNL616KjVvb1Dg8XY4/6hXooC4G2IlGkPdMb8ylvA723yvfNDHjiHSEj7PDkz7fseg/nH21zUdj2LDn+CZIcV1UCTvhOdplny2h9SuDFuF/2u12NUSrX3+vhjrxVMs30ghSUmFldArgpjikGypPa0vxVdtZcereGMNfGV0AiXs1nZ+68enrHzsW327+hWhWB1uRpcs+IE5AvSgeYhGOFohedkjZ+U69pLGhKIdPA22W9FgtPxW0efpcKpapBF3S++3C5VN0Ylx9ehtUOvitvdzJO1BXXI8G8Lrf6ufqzTe/ojZJ8OVIv47Cb+bAcYF6vCYlcc7E517/ch5IQMKaev7nN11K2X6hvCyAwn/U82W4iSta3V3sLKIpOHIhiEvg==;5:xulDizGCyvEBOm4KiqJXm0TVrBNjSNAL9G7sX1WSs0BGOSepZzv6s9GussBT2vr8i1olMYXSkMZrbAjbfQUBxDuWhfigg5PlazqFbAJQbE+V2Wtk5XPMdCFE+urJI9atzIEocV3A4oRjDZDl3SxVGISd+09a4R+Yc5yGjhwLmI8=;7:IAIgIJ5dg0N0V9nzI2Yu+hpegt8yCsuXhX12oJ/aDn1SWyM0yljhBe00vHhSfezFhAzJ0fkOqA+cGHgIiyUKutoSjC0MbQ4GD1x7qO8muA5AR0VyYnQ+NsgY7DOOClQmgofc5lxKaEqEzWS0Q0209+NHoCBaZ8BBPuFLb4mVJk4ECLnbz1STPQp7Y8nyV+saMHmb0qXRsFGarQ77FPUMBasVXswkNaMz9u5+d/shCx/hu8ixhBJBWvI+pskr+gF9 SpamDiagnosticOutput: 1:99 SpamDiagnosticMetadata: NSPM X-Microsoft-Exchange-Diagnostics: 1;DB6PR0801MB2021;20:/4/dtXdLTnF0Tiqktb++BkUwXQ5IpRo4p0R1jBQDhsAdD4u8NdXH5hH5I2nTjbp8p9LQPcfQFo6TdfqWsrrsiaEA+hbji0xTGx40sFbvQFF0pyn0aHmfncsBTYz41uD7hyV9PWd/Jz9o12cBA5tpmbNIasnxevm7TrNj319QOcs= X-OriginatorOrg: virtuozzo.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Sep 2018 15:58:46.9673 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 379f37ea-68ba-41a2-a50e-08d61e48c8d7 X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 0bc7f26d-0264-416e-a6fc-8352af79c58f X-MS-Exchange-Transport-CrossTenantHeadersStamped: DB6PR0801MB2021 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19.09.2018 18:49, Eric Dumazet wrote: > On Wed, Sep 19, 2018 at 8:41 AM Kirill Tkhai wrote: >> >> On 19.09.2018 17:55, Eric Dumazet wrote: >>> On Wed, Sep 19, 2018 at 5:29 AM Kirill Tkhai wrote: >>>> >>>> Many workloads have polling mode of work. The application >>>> checks for incomming packets from time to time, but it also >>>> has a work to do, when there is no packets. This RFC >>>> tries to develop an idea to queue RPS packets on idle >>>> CPU in the the L3 domain of the consumer, so backlog >>>> processing of the packets and the application can execute >>>> in parallel. >>>> >>>> We require this in case of network cards does not >>>> have enough RX queues to cover all online CPUs (this seems >>>> to be the most cards), and get_rps_cpu() actually chooses >>>> remote cpu, and SMP interrupt is sent. Here we may try >>>> our best, and to find idle CPU nearly the consumer's CPU. >>>> Note, that in case of consumer works in poll mode and it >>>> does not waits for incomming packets, its CPU will be not >>>> idle, while CPU of a sleeping consumer may be idle. So, >>>> not polling consumers will still be able to have skb >>>> handled on its CPU. >>>> >>>> In case of network card has many queues, the device >>>> interrupts will come on consumer's CPU, and this patch >>>> won't try to find idle cpu for them. >>>> >>>> I've tried simple netperf test for this: >>>> netserver -p 1234 >>>> netperf -L 127.0.0.1 -p 1234 -l 100 >>>> >>>> Before: >>>> 87380 16384 16384 100.00 60323.56 >>>> 87380 16384 16384 100.00 60388.46 >>>> 87380 16384 16384 100.00 60217.68 >>>> 87380 16384 16384 100.00 57995.41 >>>> 87380 16384 16384 100.00 60659.00 >>>> >>>> After: >>>> 87380 16384 16384 100.00 64569.09 >>>> 87380 16384 16384 100.00 64569.25 >>>> 87380 16384 16384 100.00 64691.63 >>>> 87380 16384 16384 100.00 64930.14 >>>> 87380 16384 16384 100.00 62670.15 >>>> >>>> The difference between best runs is +7%, >>>> the worst runs differ +8%. >>>> >>>> What do you think about following somehow in this way? >>> >>> Hi Kirill >>> >>> In my experience, scheduler has a poor view of softirq processing >>> happening on various cpus. >>> A cpu spending 90% of its cycles processing IRQ might be considered 'idle' >> >> Yes, in case of there is softirq on top of irq_exit(), the cpu is not >> considered as busy. But after MAX_SOFTIRQ_TIME (=2ms), ksoftirqd are >> waken up to execute the work in process context, and the processor is >> considered as !idle. 2ms is 2 timer ticks in case of HZ=1000. So, we >> don't restart softirq in case of it was executed for more then 2ms. >> > > That's the theory, but reality is very different unfortunately. > > If RFS/RPS is setup properly, we really do not hit MAX_SOFTIRQ_TIME condition > unless in some synthetic benchmarks maybe. > >> The similar way, single net_rx_action() can't be executed longer >> than 2ms. >> >> Having 90% load in softirq (called on top of irq_exit()) should be >> very unlikely situation, when there are too many interrupts with small >> amount of work, which related softirq calls are doing for each of them. >> I think it had be a problem even in plain napi case, since it would >> worked not like expected. >> >> But anyway. You worry, that during handling of next portion of skbs, >> we find that previous portion of skbs already woken ksoftirqd, and >> we don't see this cpu as idle? Yeah, then we'll try to change cpu, >> and this is not what we want. We want to continue use the cpu, where >> previous portion was handler. Hm, not so fast I'll answer, but certainly, >> this may be handled somehow in more creative way. >> >>> So please run a real workload (it is _very_ uncommon anyone set up RPS >>> on lo interface !) >>> >>> Like 400 or more concurrent netperf -t TCP_RR on a 10Gbit NIC. >> >> Yeah, it's just a simulation of a single irq nic. I'll try on something >> more real hardware. > > Also my concern is that you might have results that are tied to a particular > version of process scheduling, platform, workload... > > One month later, a small change in process scheduler, > and very different results. Maybe, but especially that function logic has not changed for a long time. 10 years at least. The only change is Peter adds idle core searching functionality recently. > This is why I believe this new feature must be controllable, via a new > tunable (like RPS/RFS are controllable per rx queue) > >> >> How do you execute such the tests? I don't see the appropriate parameter >> of netperf. Does this mean just to start 400 copies of netperf? How is >> to aggregate their results in this case? > > Yeah, there are various 'super_netperf' scripts available on the net > (almost trivial to write anyway) > > ( I am attaching one of them) Thanks. > Thanks. >> >>> Thanks. >>> >>> PS: Idea of playing with L3 domains is interesting, I have personally >>> tried various strategies in the past but none of them >>> demonstrated a clear win. >> >> Thanks, >> Kirill