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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 ACA18C433ED for ; Tue, 18 May 2021 01:37:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8387B613B4 for ; Tue, 18 May 2021 01:37:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345936AbhERBis (ORCPT ); Mon, 17 May 2021 21:38:48 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:3011 "EHLO szxga06-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345928AbhERBir (ORCPT ); Mon, 17 May 2021 21:38:47 -0400 Received: from dggems702-chm.china.huawei.com (unknown [172.30.72.59]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4Fkdq60j5szlfZ1; Tue, 18 May 2021 09:35:14 +0800 (CST) Received: from dggeme706-chm.china.huawei.com (10.1.199.102) by dggems702-chm.china.huawei.com (10.3.19.179) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2176.2; Tue, 18 May 2021 09:37:29 +0800 Received: from [10.67.110.108] (10.67.110.108) by dggeme706-chm.china.huawei.com (10.1.199.102) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Tue, 18 May 2021 09:37:28 +0800 Subject: Re: Virtio-scsi multiqueue irq affinity To: Thomas Gleixner , xuyihang , "Ming Lei" CC: Peter Xu , Christoph Hellwig , Jason Wang , Luiz Capitulino , "Linux Kernel Mailing List" , "Michael S. Tsirkin" , References: <20190318062150.GC6654@xz-x1> <20190325050213.GH9149@xz-x1> <20190325070616.GA9642@ming.t460p> <20190325095011.GA23225@ming.t460p> <0f6c8a5f-ad33-1199-f313-53fe9187a672@huawei.com> <87zgx5l8ck.ffs@nanos.tec.linutronix.de> <9903df53-8a84-fe89-7ae0-aac8e6d3f42f@huawei.com> <87r1ifkoq5.ffs@nanos.tec.linutronix.de> From: "liaochang (A)" Message-ID: Date: Tue, 18 May 2021 09:37:28 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.4.3 MIME-Version: 1.0 In-Reply-To: <87r1ifkoq5.ffs@nanos.tec.linutronix.de> Content-Type: text/plain; charset="gbk" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.67.110.108] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggeme706-chm.china.huawei.com (10.1.199.102) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thomas, ÔÚ 2021/5/10 15:54, Thomas Gleixner дµÀ: > Liao, > > On Mon, May 10 2021 at 11:19, liaochang wrote: >> 1.We have a machine with 36 CPUs,and assign several RT threads to last >> two CPUs(CPU-34, CPU-35). > > Which kind of machine? x86? > >> 2.I/O device driver create single managed irq, the affinity of which >> includes CPU-34 and CPU-35. > > If that driver creates only a single managed interrupt, then the > possible affinity of that interrupt spawns CPUs 0 - 35. > > That's expected, but what is the effective affinity of that interrupt? > > # cat /proc/irq/$N/effective_affinity > > Also please provide the full output of > > # cat /proc/interrupts > > and point out which device we are talking about. the mentioned managed irq is registered by virtio-scsi driver over PCI (on X86 platform, VM with 4 vCPU), as shown below. #lspci -vvv ... 00:04.0 SCSI storage controller: Virtio: Virtio SCSI Subsystem: Virtio: Device 0008 Physical Slot: 4 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- SERR- > Thanks, > > tglx > . > BR, Liao, Chang