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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id CC9DDCA0EE8 for ; Sun, 14 Sep 2025 14:31:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=LF33A9R61ZdnzfPHyrEbpe5BcMf7U3ad63kCUDGgDA0=; b=aMQus7PPuu+J2C1Pu3r/SHznl/ P6dXYDcW59iz8zXyBht9sTPaLaFpK4NrWcA1tjx26LRzwctdxwvumFRb4N8MVu6+Yg1JiUZ6NyKNB 0HS0+oDpKNyh1u0gA/i5ZH0ONVEN1uXTuiqrX4Ab3JeJ77yT8NBqR7y4T7zsJ2MK7XqSqWcShsv1p xy0wNDaIxdCsHH0JIJlenKx7gW05NkyWKSL0D58UvJoUe0r42uCq62ad5+A+QjxTm+ezq15Tl/TyK t3pbMO0lVVm7gRaweE54v7VsMnkwgoXUAs1/KiC4nQW0wVkyOR1HKYHdE1Z3FkFAUjzPv1nI6idyw Vnfk+u+g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uxnlg-00000001Wfr-0PIv; Sun, 14 Sep 2025 14:31:52 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uxnld-00000001WeV-2Vb9 for linux-nvme@lists.infradead.org; Sun, 14 Sep 2025 14:31:50 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 6B9B640506; Sun, 14 Sep 2025 14:31:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 178A4C4CEF0; Sun, 14 Sep 2025 14:31:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1757860307; bh=LF33A9R61ZdnzfPHyrEbpe5BcMf7U3ad63kCUDGgDA0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=V7q1RPbADMgafuUyPRKGurzY0ACZbnk8PxK8xXgE/xQnYzXhqZgVfCRxR8TO+o2gu ItXYYSZ/GRR8ayQP+gvhOxI2SUzbYkcxw9LMJMowXVBLgF0Rri1Qg09xlSKG/Utl7E 7YVr173tsUohj02VFrnDT1IONuPFUSuCqLwC+vDvNt808KmtXy6Y0qjkj0CradbZ5/ 5DV0X5MFEd4vxab5lvEdly4c2CaC67Q7+ZJNdRjxkYf3xT6fzsEh+k0oqvtbTHhakX BFESyxMO4uv+hy3MtwRM5af6cdmNO93Cb9bxJzcmcEs2x1AMi4ySyjU228xg/uPMKj gzJM81ImFleqw== Date: Sun, 14 Sep 2025 08:31:45 -0600 From: Keith Busch To: Apachez Cc: linux-nvme@lists.infradead.org Subject: Re: Increase maxsize of io_queue_depth for nvme driver? Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250914_073149_661239_3F15BA75 X-CRM114-Status: GOOD ( 11.26 ) 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: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Sun, Sep 14, 2025 at 02:45:35PM +0200, Apachez wrote: > I would like to propose that NVME_PCI_MAX_QUEUE_SIZE should be > increased from 4095 to 32767 to match the current NVMe specification > regarding MQES and to give the sysop ability to fully utilize the > performance of the hardware being used, or am I missing something > here? We use the upper bits of the command id to detect duplicate completions, so we don't have enough bits to tag commands beyond 4095. As far as I know, though, we haven't seen such breakage in a *long* time. It's more of a sanity thing to know with high certainty that duplicate completions are not occurring. But I don't think you'll see any performance difference by increasing the queue depth. Devices saturate the link at far lower already, so going higher just increases completion latency.