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 13087C36005 for ; Mon, 28 Apr 2025 08:04:41 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1u9JTS-00056Y-SZ; Mon, 28 Apr 2025 04:04:22 -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 1u9JTQ-00056G-TS for qemu-devel@nongnu.org; Mon, 28 Apr 2025 04:04:20 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1u9JTN-0005BF-JH for qemu-devel@nongnu.org; Mon, 28 Apr 2025 04:04:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1745827455; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=8pw7pA78OFSIvTrWwVY7D+jahxKlw2veXS/NfNwqgpY=; b=ILYNPvyIQHpOYQ1o2hfN/+WBHZxwz+j8XP5hv3ZKwOdaDl4a8VX4nnyFEXiH1rG7OYpJ9C d5RrU6Nn8UWVRZgHRzNCDayzCRVNmAnWkP/a8Pa42+51OORd6/+srRfP4eBS9rWiFmcy6a rHIyVh1r86R8RlRsZf4g/Zm89zJU4tA= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-632-vDav078DPcCAjYFNonqy_w-1; Mon, 28 Apr 2025 04:04:11 -0400 X-MC-Unique: vDav078DPcCAjYFNonqy_w-1 X-Mimecast-MFC-AGG-ID: vDav078DPcCAjYFNonqy_w_1745827450 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 670061955DDD; Mon, 28 Apr 2025 08:04:10 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.45.242.27]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id CD605180047F; Mon, 28 Apr 2025 08:04:09 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 2159D21E66C2; Mon, 28 Apr 2025 10:04:07 +0200 (CEST) From: Markus Armbruster To: Steven Sistare Cc: qemu-devel@nongnu.org, John Snow , Cleber Rosa , Eric Blake , Paolo Bonzini , "Daniel P. Berrange" , Eduardo Habkost , Fabiano Rosas , Laurent Vivier , devel@lists.libvirt.org Subject: Re: [PATCH V1 0/6] fast qom tree get In-Reply-To: <86bb6d0f-63a1-4643-b58a-1186a73e3b17@oracle.com> (Steven Sistare's message of "Wed, 9 Apr 2025 08:42:11 -0400") References: <1741036202-265696-1-git-send-email-steven.sistare@oracle.com> <87friheqcp.fsf@pond.sub.org> <86bb6d0f-63a1-4643-b58a-1186a73e3b17@oracle.com> Date: Mon, 28 Apr 2025 10:04:07 +0200 Message-ID: <87selszp8o.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -35 X-Spam_score: -3.6 X-Spam_bar: --- X-Spam_report: (-3.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.492, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=-1, RCVD_IN_MSPIKE_WL=-0.01, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, 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 Steven Sistare writes: > On 4/9/2025 3:39 AM, Markus Armbruster wrote: >> Hi Steve, I apologize for the slow response. >> >> Steve Sistare writes: >> >>> Using qom-list and qom-get to get all the nodes and property values in a >>> QOM tree can take multiple seconds because it requires 1000's of individual >>> QOM requests. Some managers fetch the entire tree or a large subset >>> of it when starting a new VM, and this cost is a substantial fraction of >>> start up time. >> >> "Some managers"... could you name one? > > My personal experience is with Oracle's OCI, but likely others could benefit. Elsewhere in this thread, we examined libvirt's use qom-get. Its use of qom-get is also noticably slow, and your work could speed it up. However, most of its use is for working around QMP interface shortcomings around probing CPU flags. Addressing these would help it even more. This makes me wonder what questions Oracle's OCI answers with the help of qom-get. Can you briefly describe them? Even if OCI would likewise be helped more by better QMP queries, your fast qom tree get work might still be useful.