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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ADC15C433EF for ; Sat, 25 Sep 2021 08:37:28 +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 4297060F70 for ; Sat, 25 Sep 2021 08:37:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 4297060F70 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=jC02dsz8NpuVz7eeeGiswuB/98Fj6YN6P+IvVq1hMow=; b=MkqNfwE6KVIcjG YF0HMhtmBuxGxCMYB2TKcc5nMYSFM2KnCv4PEH3W2fZz752r+7Sei9R7sWD1on9Tu/PZtfH9hef8H 8Lfj7tMnC9e5FX8949jKY++o/jklzxh3XXe/GCc9iYGD0RYWhRKCuxLvgJEdo0tJV2AHwI1/i6Vwy rSzMVoxxW4t4aAhed7yD8BNA1Bi08OXLyAQOzfTaSKj2j2YQ0kOCXjuxwI5kaBLf3doBY8ofSnLmK F0BwZr123EoR3rZvn1GtFYxcULAoUo1VdiIe9OfNgtKZlPaFbSf183CNnwWKsugJ7rYzCHe/Nm+PD vYqzTtkbKNUdmRwarUjw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mU3B5-00GIyq-0W; Sat, 25 Sep 2021 08:36:59 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mU3B3-00GIyj-UO for linux-nvme@bombadil.infradead.org; Sat, 25 Sep 2021 08:36:57 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=StgiqVvzYvvcYGkPsgijWPfPh4tFTA+W5zpqd7GAsYo=; b=KBtItcqkSA9AI6758jMUW45Cx8 yGdXWcK/fqgPhVXQBzzMMOwjnI19+Btap7k1anTRW0Vjp3bIyOfhHcOsZh5vCD1gUHSPDSVhuQH4p bLfext3x0IaCg+DcZ+TFHvyrd5q6ArgYJaDljXWt+/V4mak2VtzyIFauV3Nc6d6Xah0RQ8J76CcU9 VQBUMuzxV0vjS8dVoexhMkDj7isdu3tYaJ4Xfy6JReHxu9xwKOXs+dGuScBsSwScIyanyRywbKUOc DpidlAaxzWz4NP7ZN7FF279U5bSbMxiHuNtr3Qjv/g2hTgxvh1wZ4KrlyEaVupjerpyOLML8GApHq //qHoH5A==; Received: from hch by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mU3AL-007xbZ-CX; Sat, 25 Sep 2021 08:36:31 +0000 Date: Sat, 25 Sep 2021 09:36:13 +0100 From: Christoph Hellwig To: Benjamin Herrenschmidt Cc: Keith Busch , Andrey Nikitin , linux-nvme@lists.infradead.org, davebuch@amazon.com Subject: Re: [RFC PATCH 0/3] nvme sq associations Message-ID: References: <20210924210809.14536-1-nikitina@amazon.com> <20210925030207.GA20848@redsun51.ssa.fujisawa.hgst.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 On Sat, Sep 25, 2021 at 06:31:58PM +1000, Benjamin Herrenschmidt wrote: > On Sat, 2021-09-25 at 12:02 +0900, Keith Busch wrote: > > > > Different submission queue groups per NVM Set sounds right for this > > feature, but I'm not sure it makes sense for these to have their own > > completion queues: completions from different sets would try to > > schedule on the same CPU. I think it should be more efficient to > > break the 1:1 > > SQ:CQ pairing, and instead have all the SQs with the same CPU > > affinity share a single CQ so that completions from different > > namespaces could be handled in a single interrupt. > > Can this be an incremental improvement ? Honestly I'd rather not merge this whole patchset at all. It is a completly frinde feature for a totally misdesigned part of the NVMe spec. Until actual controller in the hands of prosumers support anything like that I'm very reluctant to bloat the driver fast path for it. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme