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 DCA07C48BEB for ; Thu, 22 Feb 2024 07:10:45 +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:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=TdNiqR94XdKRLVz+UnIF0xVb0mc+BTJ4sVoFD9fzPTE=; b=Qc1daPj47g5Vys5gsHEwzCMYfu y+Ojpo1sL3uNu4Uf+oHS6dVzSEP5e0edCAWQrEjUGepupeOXWuEKOFrv5ZfGbF2c2AY0voCT/kNHy TjBhYpWfn9XyV3W10QINnFkt+tMjo4brw4brtq0ZX2kaguJocUmX4wI4PdCEo4I4aH828IG/YdhI0 0ljO4VdID5Bc6kk4usKhT74hCCVoBGLpAE1Lr6HXruQvuLK82lXw6AlT62Vd0MeuEcZVx6eoMffcm b4zxf5di9mnmka4YcOOP1NL/JYL1br8ZlhU0iBhjzAMVRIU6SaUXFXAlgza1h4kSJd49rV787x61H B1neCU9g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rd3EC-00000003mEZ-200l; Thu, 22 Feb 2024 07:10:44 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rd3E5-00000003mE0-18m1 for linux-nvme@lists.infradead.org; Thu, 22 Feb 2024 07:10:38 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id AC46761729; Thu, 22 Feb 2024 07:10:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CCB6DC433F1; Thu, 22 Feb 2024 07:10:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1708585836; bh=ehJxGfsAI6x77Kpzx66U6ws6VdAWkR1Sdx+/AOqqlzs=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=LThS3IwNuaVT8l/FEr3X0WlskZC1hHuKXvi9IQpXxZ2wRT0FZv0KcZNIFW+HFQHiB 43Xw9oROO1cIISuPEE5dFDTRjPfdEUUsymyQSDA4jY2uZVdoO6AQMsnsXGsl35SVVv bgiRFv4LKzXBVkaJiNZkkXi4Je0nDbacTUkV1vsGt+xqkGHk6hh9PUYqaCu3CFQ9cA FNBBU1p6VjLUYQi8ZIllA4tRvyX7f/U6xAG0Gs0C3HSHalLej1jFjixbH9UBdtR1Dj n6K3L2xtYG/wqb+UCwjveSGfp52IN+ksSXBonKh3wEMtTXycJoRzW5txN5Hans36Ju T7WdWrFSBxTvQ== Message-ID: <53d746b8-a24e-45ac-ab70-c0a0cae6f4eb@kernel.org> Date: Thu, 22 Feb 2024 16:10:34 +0900 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [LSF/MM/BPF TOPIC] Adding NVMeVirt to Kernel mainline Content-Language: en-US To: Jaehoon Shim , lsf-pc@lists.linux-foundation.org Cc: linux-nvme@lists.infradead.org References: From: Damien Le Moal Organization: Western Digital Research In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240221_231037_393572_F71461A7 X-CRM114-Status: GOOD ( 14.70 ) 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 2/22/24 10:38, Jaehoon Shim wrote: > Hi all, > > My research group has recently introduced NVMeVirt, a software-defined > virtual NVMe device implemented as a Linux kernel module. Upon > loading, NVMeVirt emulates an NVMe device that is recognized by the > host as a native PCIe device. > - https://github.com/snu-csl/nvmevirt > - https://www.usenix.org/system/files/fast23-kim.pdf > > Advantages of NVMeVirt are: > - Deployable in real environments (not virtual) > - PCI peer-to-peer DMA support > - Low-latency device support > - Multiple namespace support (each namespace can support different command sets) > - Multiple device support > - Various command set support (currently supporting ZNS and KV) > - Accurate performance emulation > > What if we can simplify NVMeVirt and add it to the Kernel mainline > just like the scsi_debug in the SCSI driver? This would offer an > accessible tool for developers, especially when NVMe devices with > specific spec are unavailable, to develop and debug the NVMe driver > functionalities. Qemu emulates nvme devices fairly well already. What is the backing store for you kernel module nvme emulation ? Memory only ? files or block device ? If it is the latter, how can you do "Accurate performance emulation". And what does "Accurate performance emulation" mean anyway ? Different NVMe drives from the same or different vendors have different performance characteristics. So what exactly are you emulating here ? > > Best regards, > Jaehoon > -- Damien Le Moal Western Digital Research