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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1FAA5C433EF for ; Sat, 19 Feb 2022 07:37:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241654AbiBSHiF (ORCPT ); Sat, 19 Feb 2022 02:38:05 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:46416 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234270AbiBSHiF (ORCPT ); Sat, 19 Feb 2022 02:38:05 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EBD584E3B9; Fri, 18 Feb 2022 23:37:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=h57KiAEVSKkzXdNc8Dx5lCWM++DN28M84mRcDiV5fkY=; b=KsxrcfYaerfj7S4ITWFvQAQ0x6 24aeSlzHZ3cmMdzzDJjwD5MH7BiCBtomrZK+sUouoLD9vIJHuUOIq8hNC2rT9TREsjqowo7ZigLPU llG/bACQNWJM62cm7Wc1o0o5yl4BeuJOK1InpRSg6F2nlLE+wMwB6Sr0Gv2APOv6ZKnh4XB2/bx0q pO/NM0jEjfo63HNdo4QypAR7fM098sBkqtoJnexaTDGT2EC9VuGERlxc6rMnA1xJW3+p1h+TLVuCS Lhtn1UlZlZPW5MAURTUYVTtlIOcC7djUDixNNJ6pg7uXqJlAMgXvaRfk2N49sHxK0dt49GFiuTp9+ u3rD/Uaw==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nLKIh-00GNfs-Pt; Sat, 19 Feb 2022 07:37:03 +0000 Date: Fri, 18 Feb 2022 23:37:03 -0800 From: Christoph Hellwig To: "Melanie Plageman (Microsoft)" Cc: mikelley@microsoft.com, jejb@linux.ibm.com, kys@microsoft.com, martin.petersen@oracle.com, mst@redhat.com, benh@kernel.crashing.org, decui@microsoft.com, don.brace@microchip.com, R-QLogic-Storage-Upstream@marvell.com, haiyangz@microsoft.com, jasowang@redhat.com, john.garry@huawei.com, kashyap.desai@broadcom.com, mpe@ellerman.id.au, njavali@marvell.com, pbonzini@redhat.com, paulus@samba.org, sathya.prakash@broadcom.com, shivasharan.srikanteshwara@broadcom.com, sreekanth.reddy@broadcom.com, stefanha@redhat.com, sthemmin@microsoft.com, suganath-prabu.subramani@broadcom.com, sumit.saxena@broadcom.com, tyreld@linux.ibm.com, wei.liu@kernel.org, linuxppc-dev@lists.ozlabs.org, megaraidlinux.pdl@broadcom.com, mpi3mr-linuxdrv.pdl@broadcom.com, storagedev@microchip.com, virtualization@lists.linux-foundation.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, MPT-FusionLinux.pdl@broadcom.com, andres@anarazel.de Subject: Re: [PATCH RFC v1 0/5] Add SCSI per device tagsets Message-ID: References: <20220218184157.176457-1-melanieplageman@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220218184157.176457-1-melanieplageman@gmail.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On Fri, Feb 18, 2022 at 06:41:52PM +0000, Melanie Plageman (Microsoft) wrote: > Currently a single blk_mq_tag_set is associated with a Scsi_Host. When SCSI > controllers are limited, attaching multiple devices to the same controller is > required. In cloud environments with relatively high latency persistent storage, > requiring all devices on a controller to share a single blk_mq_tag_set > negatively impacts performance. So add more controllers instead of completely breaking the architecture.