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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 438CAD24470 for ; Fri, 11 Oct 2024 17:22:19 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1szJ41-0000ky-3H; Fri, 11 Oct 2024 13:04:29 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1szJ3z-0000hu-45 for qemu-devel@nongnu.org; Fri, 11 Oct 2024 13:04:27 -0400 Received: from mx.treblig.org ([2a00:1098:5b::1]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1szIu0-0000Ot-J1 for qemu-devel@nongnu.org; Fri, 11 Oct 2024 12:54:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=treblig.org ; s=bytemarkmx; h=Content-Type:MIME-Version:Message-ID:Subject:From:Date:From :Subject; bh=Ny+BSiVefvk0ZMxyxY5jJ/ox0PnbAIotPo5Wo2LKZTs=; b=A+gz1v79zbYY8F2z GIoA5M4hlx3+UQfnBxbtaJFeUnuHTz9/kKSUtayM6WazHwSf0QfQQ+XxYmUirY6v4y8x379ObIAvb jAnnBuA6qC8oIcjdeKvlUVFRoaiJSfgybsF0QGQqP/6kvdnn+J3tfCKx6sxnbu5kq0WSsapyIq++N yT4FeNmCqANyeD/aC01BPuEaBDIH1O1vwluPL5LdVnIe5Mqawc7sd+jakPRZi6wiIK8bs48r5d0ey ztR7XfcEpXONdQJa4/NgMkDZCX9ySg071DwXGPKAFb1sbGzvJz47rQ96zgaMdysw9C/tjXyqU4TfA gBQIVhwnEeagAicTGA==; Received: from dg by mx.treblig.org with local (Exim 4.96) (envelope-from ) id 1szIto-00AZ2q-2i; Fri, 11 Oct 2024 16:53:56 +0000 Date: Fri, 11 Oct 2024 16:53:56 +0000 From: "Dr. David Alan Gilbert" To: Peter Xu Cc: Yichen Wang , Paolo Bonzini , =?iso-8859-1?Q?Marc-Andr=E9?= Lureau , Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= , Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= , Fabiano Rosas , Eric Blake , Markus Armbruster , "Michael S. Tsirkin" , Cornelia Huck , qemu-devel@nongnu.org, Hao Xiang , "Liu, Yuan1" , Shivam Kumar , "Ho-Ren (Jack) Chuang" Subject: Re: [PATCH v6 00/12] Use Intel DSA accelerator to offload zero page checking in multifd live migration. Message-ID: References: <20241009234610.27039-1-yichen.wang@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: X-Chocolate: 70 percent or better cocoa solids preferably X-Operating-System: Linux/6.1.0-21-amd64 (x86_64) X-Uptime: 16:52:40 up 156 days, 4:06, 1 user, load average: 0.03, 0.03, 0.00 User-Agent: Mutt/2.2.12 (2023-09-09) Received-SPF: pass client-ip=2a00:1098:5b::1; envelope-from=dg@treblig.org; helo=mx.treblig.org X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org * Peter Xu (peterx@redhat.com) wrote: > The doc update is still missing under docs/, we may need that for a final > merge. > > Are you using this in production? How it performs in real life? What is > the major issue to solve for you? Is it "zero detect eats cpu too much", > or "migration too slow", or "we're doing experiment with the new hardwares, > and see how it goes if we apply it on top of migrations"? > > There're a lot of new code added for dsa just for this optimization on zero > page detection. We'd better understand the major benefits, and also > whether that's applicable to other part of qemu or migration-only. I > actually wonder if we're going to support enqcmd whether migration is the > best starting point (rather than other places where we emulate tons of > devices, and maybe some backends can speedup IOs with enqcmd in some > form?).. but it's more of a pure question. The other thing that worries me here is that there's not much abstraction, I'm sure there's a whole bunch of offload cards that could do tricks like this; how do we avoid having this much extra code for each one? Dave > > Thanks, > > -- > Peter Xu > -- -----Open up your eyes, open up your mind, open up your code ------- / Dr. David Alan Gilbert | Running GNU/Linux | Happy \ \ dave @ treblig.org | | In Hex / \ _________________________|_____ http://www.treblig.org |_______/