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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 7214BC433E0 for ; Wed, 24 Jun 2020 06:53:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 58C082072E for ; Wed, 24 Jun 2020 06:53:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389472AbgFXGxC (ORCPT ); Wed, 24 Jun 2020 02:53:02 -0400 Received: from verein.lst.de ([213.95.11.211]:43030 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388972AbgFXGxC (ORCPT ); Wed, 24 Jun 2020 02:53:02 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id ACFC668B05; Wed, 24 Jun 2020 08:52:58 +0200 (CEST) Date: Wed, 24 Jun 2020 08:52:58 +0200 From: Christoph Hellwig To: Baolin Wang Cc: kbusch@kernel.org, axboe@fb.com, hch@lst.de, sagi@grimberg.me, baolin.wang7@gmail.com, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/2] nvme: Add Arbitration Burst support Message-ID: <20200624065258.GA18130@lst.de> References: <32d99c016d23d660f5be4a9754b5b9aafe81ab6c.1592980985.git.baolin.wang@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <32d99c016d23d660f5be4a9754b5b9aafe81ab6c.1592980985.git.baolin.wang@linux.alibaba.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 24, 2020 at 02:49:57PM +0800, Baolin Wang wrote: > >From the NVMe spec, "In order to make efficient use of the non-volatile > memory, it is often advantageous to execute multiple commands from a > Submission Queue in parallel. For Submission Queues that are using > weighted round robin with urgent priority class or round robin > arbitration, host software may configure an Arbitration Burst setting". > Thus add Arbitration Burst setting support. What is the value add of doing this in the kernel? Wouldn't a nvme-cli subcommand to just set the arbitration burst to the recommended value, either as a saved or current value be both more useful and also cause less kernel bloat?