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 02DF2C197A0 for ; Fri, 17 Nov 2023 12:05:41 +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 551072B057 for ; Fri, 17 Nov 2023 12:05:41 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 2A04D986E2B for ; Fri, 17 Nov 2023 12:05:41 +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 10D3E986E1E; Fri, 17 Nov 2023 12:05:41 +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 0349E986E1F for ; Fri, 17 Nov 2023 12:05:02 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: 4inwTn4ePtKTYtiFdEsxuQ-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700222698; x=1700827498; 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=uSThxtXr9DepuZS5pln7sEQDA0zlhcDQUBA8K9dYSJA=; b=sjln6cXraJyzRJ7hqufo5cGNscRbk3Or5IJRiLHVnevl0bnCuI8sWAB+q/0zbmj61d tHQgiuRl/oO4/E3eoDZ5TrpT23MWisUROwgTElWqpvjgRoZtMeWEaltY2ly2gV4SoE7/ MQ7aJPpuvp7OrqlGLutdDm4fOWcPZSm80JRfa/UVs1XGfEW30bPSabp1eG/0r9NKGz1R KV7sPmLyaxvxfIsB/SMBHwqbklBfUG3Z7y0V5VwHxZ0mEpSKAWypgXge17R54uibyff/ q6KQdzL7gvgQJ6XYJrdxWfvJFJkYiKuVxPfNHtySn/y299u1PzBmxQZIX4K6Xp+HSR60 YJHQ== X-Gm-Message-State: AOJu0YzhwlqhXJQHWou23SFD0qWj9kSskGSjjWFfO6K/9nhQjsrk94iP CMg0iGrPXfY/6fB0cVEq+wJwhMRep10WEA+NHoGSOaUtK1Gcmtimqdiv6h3NB9WHYsfzj02ZNwx k7P8OZBdD/gO8I80v7OipRFW6r6GGY6C0fA== X-Received: by 2002:a05:600c:4fd2:b0:408:434c:dae7 with SMTP id o18-20020a05600c4fd200b00408434cdae7mr16958683wmq.2.1700222698475; Fri, 17 Nov 2023 04:04:58 -0800 (PST) X-Google-Smtp-Source: AGHT+IGXoojUc6gt6KxqnGEekKBbGfwRqSi7DBczNyb0VFoF/Mq+zbs4Y0I1vjctgwOgx/p5rZVPdw== X-Received: by 2002:a05:600c:4fd2:b0:408:434c:dae7 with SMTP id o18-20020a05600c4fd200b00408434cdae7mr16958656wmq.2.1700222698086; Fri, 17 Nov 2023 04:04:58 -0800 (PST) Date: Fri, 17 Nov 2023 07:04:51 -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: <20231117065740-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> <20231117063304-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 11:45:20AM +0000, Parav Pandit wrote: > > > From: Michael S. Tsirkin > > Sent: Friday, November 17, 2023 5:04 PM > > > > 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. > > Common config: 8+8 tx and rx queues. > Port speed: 100Gbps > QEMU 8.1 > Libvirt 7.0 > GVM: Centos 7.4 > Device: virtio VF hardware device > > Config_1: virtio suspend/resume similar to what Lingshan has, largely vdpa stack > Config_2: Device context method of admin commands OK that sounds good. The weird thing here is that you measure "downtime". What exactly do you mean here? I am guessing it's the time to retrieve on source and re-program device state on destination? And this is 3.71x out of how long? -- 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/