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 6B08EC54FB9 for ; Thu, 16 Nov 2023 12:00:05 +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 AAEFA133341 for ; Thu, 16 Nov 2023 12:00:04 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 850A0986DEB for ; Thu, 16 Nov 2023 12:00:04 +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 4186F986DDD; Thu, 16 Nov 2023 12:00:04 +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 26C3D986DDE for ; Thu, 16 Nov 2023 12:00:04 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: t-y_AVutMNuGUV_cMqZW4w-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700136000; x=1700740800; 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=uXBV4jOTZrO+hYk4rqWetQSUrWM13DqSKjZIJH4uQe8=; b=VbWiXEpolUFza6NCm7e7BY+5a0CQC+YRyJp5+52Eme2tS8vSUo/m19Mpbg8kYNSxsk qwCqub4XDMZCWpADPF8iScN2e3UFGeI3pNltsGFvz8eLSy45nhkY+CKqQX2bhPO4C98a uvUrsvsUE6fap2512k0KhPT8RkIDGYnCBmCaU1L1mNw6gb813sVEAwjMlIFo3xP+ABNb HUeQWybe+VFKcf/+9npdNYJ3vmz+fwquz9oIMdmTs9FKcJb8aerbAPNzmr14tMaA8b/S 0CHSgqcpDXTsABW8EbgsL7ZliQ2izsQSZIlgUVoqvrNF0OEQjq1JGYRTnVx7yl5fwYFV Ywjw== X-Gm-Message-State: AOJu0YyWsCubfNzrk7+IT4qCefvR//5zwSl85azWIdL8oAbHZ4y2Yf2e 8HkJrd1OeAIxyabU5d7nmMHELqhvlazV1leNQYHcE8hr973zYMm1n0hKWzJ0fS+6ZRZqBXtIh4d MWiHa7oxUd0/QpDC6PijXUh3ebppZvXT+mQ== X-Received: by 2002:a05:6512:3e26:b0:507:9740:b6db with SMTP id i38-20020a0565123e2600b005079740b6dbmr14822244lfv.67.1700136000282; Thu, 16 Nov 2023 04:00:00 -0800 (PST) X-Google-Smtp-Source: AGHT+IHI7HtgXawT24nXYiltYeVY1hFyPVmR8+TidQBt851JTf6sT/49JDyuRhWo16wViTXfVdPpsQ== X-Received: by 2002:a05:6512:3e26:b0:507:9740:b6db with SMTP id i38-20020a0565123e2600b005079740b6dbmr14822219lfv.67.1700135999920; Thu, 16 Nov 2023 03:59:59 -0800 (PST) Date: Thu, 16 Nov 2023 06:59:55 -0500 From: "Michael S. Tsirkin" To: "Zhu, Lingshan" Cc: Parav Pandit , Jason Wang , "virtio-comment@lists.oasis-open.org" , "cohuck@redhat.com" , "sburla@marvell.com" , Shahaf Shuler , Maor Gottlieb , Yishai Hadas Message-ID: <20231116065416-mutt-send-email-mst@kernel.org> References: <20231116004037-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 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. > For dirty page tracking, I see you want both platform IOMMU tracking and > shadow vqs, I am > totally fine with this idea. And I think maybe we should merge the basic > features first, and > dirty page tracking should be the second step. > > Thanks Parav wants to add an option of on-device tracking. Which also seems fine. I think it should be optional though because shadow and IOMMU options exist. -- 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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