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 1E4FFC197A0 for ; Fri, 17 Nov 2023 12:32:40 +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 7481745B33 for ; Fri, 17 Nov 2023 12:32:39 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 3E385986E30 for ; Fri, 17 Nov 2023 12:32:39 +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 221AA986E1E; Fri, 17 Nov 2023 12:32:39 +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 13426986E1F for ; Fri, 17 Nov 2023 12:32:39 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: KiyAzKFdNIy6dxx3BVT8oQ-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700224353; x=1700829153; 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=LjCAnAbdZri9p3zo3cmNUTXvDFdL0l8do6ldCBMUCHo=; b=u53eF39tF1Ui5vPAtoteS/9GzjNcDQBY4Fzd6FQVwIFk6gVduDEKw06dbklsxNNcVc HO/pmXSia9EtMN38+x+hXZccx5ZSsFxtMXck45IVdxhw5GiMUR35oUhMwCmRc9auyRsh VObfG9kDNFNhvaOCqyW+BsLx+jYPX+2utyPFrmkKi4UHA6P6GDnxUN8dqdCOHHeHUikT xgdb9bKq4DXtBV1wnnWdSFccpjgt4nl10Twr05Qsa1WCovVdXtSVpuw7sFScJh9oRH24 3unxJS4Vkv8Q7EL877bIifC+zC0bGMqzJsVd2nKEZ8RY6fidXQv4oqGrODxzAr8uVQkG c76g== X-Gm-Message-State: AOJu0Yxa2WiBhkF14qSwCgW60Z2LjR+XINaNztRShNb6HZBzOThfLYKW SVHXXRaXFdJIoQ92E0t5Xka6ZyYPCUBS2yLpr1YYvbvWPjz4xPZbBM1PFylnWYPrL1asup4QZB8 P1u1RsFDyv4mkrgssHgfNdQBQv9IAabyyQQ== X-Received: by 2002:ac2:58c6:0:b0:504:7bb0:9d7e with SMTP id u6-20020ac258c6000000b005047bb09d7emr10265416lfo.27.1700224352969; Fri, 17 Nov 2023 04:32:32 -0800 (PST) X-Google-Smtp-Source: AGHT+IFuTCMSzlecWUXl18gvplrsn/gVLQAZTc3sYnPe5j4z1PQwNtViXCQGTlDdgrrWJCGpE+CEMQ== X-Received: by 2002:ac2:58c6:0:b0:504:7bb0:9d7e with SMTP id u6-20020ac258c6000000b005047bb09d7emr10265411lfo.27.1700224352609; Fri, 17 Nov 2023 04:32:32 -0800 (PST) Date: Fri, 17 Nov 2023 07:32:24 -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: <20231117073031-mutt-send-email-mst@kernel.org> References: <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> <20231117065740-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 12:11:15PM +0000, Parav Pandit wrote: > > > > From: Michael S. Tsirkin > > Sent: Friday, November 17, 2023 5:35 PM > > To: Parav Pandit > > > > 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? > Yes. Downtime is the time during which the VM is not responding or receiving packets, which involves reprogramming the device. > 3.71x is relative time for this discussion. Oh interesting. So VM state movement including reprogramming the CPU is dominated by reprogramming this single NIC, by a factor of almost 4? CAn we get some absolute numbers too, please? -- 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. 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