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 ws5-mx01.kavi.com (ws5-mx01.kavi.com [34.193.7.191]) (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 BC99DC072A2 for ; Fri, 17 Nov 2023 11:35:29 +0000 (UTC) Received: from lists.oasis-open.org (oasis.ws5.connectedcommunity.org [10.110.1.242]) by ws5-mx01.kavi.com (Postfix) with ESMTP id 2E79E157EAA for ; Fri, 17 Nov 2023 11:35:29 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 0CDEA986E20 for ; Fri, 17 Nov 2023 11:35:29 +0000 (UTC) Received: from host09.ws5.connectedcommunity.org (host09.ws5.connectedcommunity.org [10.110.1.97]) by lists.oasis-open.org (Postfix) with QMQP id E12DD986E1D; Fri, 17 Nov 2023 11:35:28 +0000 (UTC) Mailing-List: contact virtio-comment-help@lists.oasis-open.org; run by ezmlm List-ID: Sender: Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 4F781986E1E for ; Fri, 17 Nov 2023 11:34:02 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: 1rsRA3r5NL-K_OzB9036-Q-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700220838; x=1700825638; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=NzIKJQiGPAl6K0i0jA8OFObniyKWkAUjEU2tv2KaXhw=; b=IDPvwhyXrZxFpsx1nkBEG5BIoNYZIUy4mwRvxcXjYNLJnwT5BxRhnBuZu7N2DpNnL8 HzAnG6tcYEc9EU09kd6f2brxAAwTfeXCb7TmXfp9ruj2BYVi9+f3PGKBAQCsQvn1na4t OyqRifqPwHtrwg/tutN3BZqmnqpxavBJX0KAlhDpAKdaUXd9x2tAxbknR/oqOPmWb783 Dxy8jeGRlHuIIQYLrSJzFF4nPVKj3CspP43/TYCIYu8dVjG61J3zN+Sx6ZEXcQFy/4jv JRphL9eobuHZ+ZZuC6k13Ayc0XmgI3KGJpWpnLj69s4cPiVnkRtVirhAMeSTAphecV4M 6dvA== X-Gm-Message-State: AOJu0Yz15qah2kj3OjYyISRCmDA8E3bHSnp6jNIzcxj84eSJRH7xsrCc T+bD9Uu+9TgeCmeJKQRMJ6CJEMd8Juy4Z14gsPLofmRG4AATrKAwR5r9h6ebk061u0O5GQNUvDY 6k7LfCco9JxphqWo36DzD87ilyC8jCEIZBA== X-Received: by 2002:a05:6000:1446:b0:32f:91d2:6f1b with SMTP id v6-20020a056000144600b0032f91d26f1bmr14364580wrx.5.1700220838579; Fri, 17 Nov 2023 03:33:58 -0800 (PST) X-Google-Smtp-Source: AGHT+IHOSQm2XTpPHeveYfTC/2UJX0Rt010UEWwirs0MKwlUQR+RJrXvP/ttejW3oouCXFB70StMOA== X-Received: by 2002:a05:6000:1446:b0:32f:91d2:6f1b with SMTP id v6-20020a056000144600b0032f91d26f1bmr14364561wrx.5.1700220838195; Fri, 17 Nov 2023 03:33:58 -0800 (PST) Date: Fri, 17 Nov 2023 06:33:51 -0500 From: "Michael S. Tsirkin" To: Parav Pandit Cc: "Zhu, Lingshan" , Jason Wang , "virtio-comment@lists.oasis-open.org" , "cohuck@redhat.com" , "sburla@marvell.com" , Shahaf Shuler , Maor Gottlieb , Yishai Hadas Message-ID: <20231117063304-mutt-send-email-mst@kernel.org> References: <20231116004037-mutt-send-email-mst@kernel.org> <20231116065416-mutt-send-email-mst@kernel.org> <705e728a-368a-4e28-a7b2-61afddb15ce9@intel.com> <20231117054650-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Subject: Re: [virtio-comment] Re: [PATCH v3 6/8] admin: Add theory of operation for write recording commands On Fri, Nov 17, 2023 at 11:05:16AM +0000, Parav Pandit wrote: > > > > From: Michael S. Tsirkin > > Sent: Friday, November 17, 2023 4:30 PM > > > > On Fri, Nov 17, 2023 at 10:03:47AM +0000, Parav Pandit wrote: > > > > > > > > > > From: Zhu, Lingshan > > > > Sent: Friday, November 17, 2023 3:30 PM > > > > > > > > On 11/16/2023 7:59 PM, Michael S. Tsirkin wrote: > > > > > On Thu, Nov 16, 2023 at 06:28:07PM +0800, Zhu, Lingshan wrote: > > > > >> > > > > >> On 11/16/2023 1:51 PM, Michael S. Tsirkin wrote: > > > > >>> On Thu, Nov 16, 2023 at 05:29:54AM +0000, Parav Pandit wrote: > > > > >>>> We should expose a limit of the device in the proposed > > > > WRITE_RECORD_CAP_QUERY command, that how much range it can track. > > > > >>>> So that future provisioning framework can use it. > > > > >>>> > > > > >>>> I will cover this in v5 early next week. > > > > >>> I do worry about how this can even work though. If you want a > > > > >>> generic device you do not get to dictate how much memory VM has. > > > > >>> > > > > >>> Aren't we talking bit per page? With 1TByte of memory to track > > > > >>> -> 256Gbit -> 32Gbit -> 8Gbyte per VF? > > > > >>> > > > > >>> And you happily say "we'll address this in the future" while at > > > > >>> the same time fighting tooth and nail against adding single bit > > > > >>> status registers because scalability? > > > > >>> > > > > >>> > > > > >>> I have a feeling doing this completely theoretical like this is problematic. > > > > >>> Maybe you have it all laid out neatly in your head but I suspect > > > > >>> not all of TC can picture it clearly enough based just on spec text. > > > > >>> > > > > >>> We do sometimes ask for POC implementation in linux / qemu to > > > > >>> demonstrate how things work before merging code. We skipped this > > > > >>> for admin things so far but I think it's a good idea to start > > > > >>> doing it here. > > > > >>> > > > > >>> What makes me pause a bit before saying please do a PoC is all > > > > >>> the opposition that seems to exist to even using admin commands > > > > >>> in the 1st place. I think once we finally stop arguing about > > > > >>> whether to use admin commands at all then a PoC will be needed > > before merging. > > > > >> We have POR productions that implemented the approach in my series. > > > > >> They are multiple generations of productions in market and > > > > >> running in customers data centers for years. > > > > >> > > > > >> Back to 2019 when we start working on vDPA, we have sent some > > > > >> samples of production(e.g., Cascade Glacier) and the datasheet, > > > > >> you can find live migration facilities there, includes suspend, > > > > >> vq state and other features. > > > > >> > > > > >> And there is an reference in DPDK live migration, I have provided > > > > >> this page > > > > >> before: > > > > >> https://doc.dpdk.org/guides-21.11/vdpadevs/ifc.html, it has been > > > > >> working for long long time. > > > > >> > > > > >> So if we let the facts speak, if we want to see if the proposal > > > > >> is proven to work, I would > > > > >> say: They are POR for years, customers already deployed them for years. > > > > > And I guess what you are trying to say is that this patchset we > > > > > are reviewing here should be help to the same standard and there > > > > > should be a PoC? Sounds reasonable. > > > > Yes and the in-marketing productions are POR, the series just > > > > improves the design, for example, our series also use registers to > > > > track vq state, but improvements than CG or BSC. So I think they are proven > > to work. > > > > > > If you prefer to go the route of POR and production and proven documents > > etc, there is ton of it of multiple types of products I can dump here with open- > > source code and documentation and more. > > > Let me know what you would like to see. > > > > > > Michael has requested some performance comparisons, not all are ready to > > share yet. > > > Some are present that I will share in coming weeks. > > > > > > And all the vdpa dpdk you published does not have basic CVQ support when I > > last looked at it. > > > Do you know when was it added? > > > > It's good enough for PoC I think, CVQ or not. > > The problem with CVQ generally, is that VDPA wants to shadow CVQ it at all > > times because it wants to decode and cache the content. But this problem has > > nothing to do with dirty tracking even though it also mentions "shadow": > > if device can report it's state then there's no need to shadow CVQ. > > For the performance numbers with the pre-copy and device context of patches posted 1 to 5, the downtime reduction of the VM is 3.71x with active traffic on 8 RQs at 100Gbps port speed. Sounds good can you please post a bit more detail? which configs are you comparing what was the result on each of them. -- MST This publicly archived list offers a means to provide input to the OASIS Virtual I/O Device (VIRTIO) TC. In order to verify user consent to the Feedback License terms and to minimize spam in the list archive, subscription is required before posting. Subscribe: virtio-comment-subscribe@lists.oasis-open.org Unsubscribe: virtio-comment-unsubscribe@lists.oasis-open.org List help: virtio-comment-help@lists.oasis-open.org List archive: https://lists.oasis-open.org/archives/virtio-comment/ Feedback License: https://www.oasis-open.org/who/ipr/feedback_license.pdf List Guidelines: https://www.oasis-open.org/policies-guidelines/mailing-lists Committee: https://www.oasis-open.org/committees/virtio/ Join OASIS: https://www.oasis-open.org/join/