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 A62EBC54756 for ; Mon, 19 May 2025 21:19:41 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uH7tA-00009Q-Ae; Mon, 19 May 2025 17:19:12 -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 1uH7t8-000092-QT for qemu-devel@nongnu.org; Mon, 19 May 2025 17:19:10 -0400 Received: from smtp-out1.suse.de ([2a07:de40:b251:101:10:150:64:1]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1uH7t6-00057I-QX for qemu-devel@nongnu.org; Mon, 19 May 2025 17:19:10 -0400 Received: from imap1.dmz-prg2.suse.org (unknown [10.150.64.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 3A14022083; Mon, 19 May 2025 21:19:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1747689545; h=from:from:reply-to: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=V1WzxLYGWzDYKGwvt2++Tx9dud6RxSPD+p5MAgJEWO0=; b=J9NT7LPdf9V4/tcnabWRbmGsGGXr3jtx8QUVF7juV/PnilYiu2pLt05fVQV36upYGTkDbf hwETkjBredM8rINx9OoUR0mOKqY08pPBYuOUQrZ2JzzxkmdVLwqx76eRz3hBnKJl1DSb2q ahSzDWf+FJp9DAvcjgcUthTPNkrLVpU= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1747689545; h=from:from:reply-to: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=V1WzxLYGWzDYKGwvt2++Tx9dud6RxSPD+p5MAgJEWO0=; b=6AyCmeNIosxFmBXw66XOqo14GgURbsk2t9yPki2kUIuj5Ry6aH8aYa9mlYEKTCB7fv0+7q K/MYhep9q/4+tBCA== Authentication-Results: smtp-out1.suse.de; none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1747689544; h=from:from:reply-to: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=V1WzxLYGWzDYKGwvt2++Tx9dud6RxSPD+p5MAgJEWO0=; b=xsjy7mOR0IYe+r/Ft4+4qSBV4YzOkFhibD95f1HU61hodSXJAIICKIc597UNgbUvv8Y7lb Ix6RPBTl6vksscClBW5dYzXfH8qUHfbb5s05CysbNL/1JW4O0mESt5FwSXuW8n2rmuUWql /j0PJ5rmbxaffJ9JDL9SugS2Qvc3gyQ= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1747689544; h=from:from:reply-to: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=V1WzxLYGWzDYKGwvt2++Tx9dud6RxSPD+p5MAgJEWO0=; b=Uy8QGdrHSIp7HrMxIjWH8McRMiEygW/eX0SvUrfkGBObOikI1+iqC3E4RoKRdjFEEjiLkz VfJSjUvmyArbxrCw== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 8DBD513A30; Mon, 19 May 2025 21:19:03 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id hPVtE0egK2jtJAAAD6G6ig (envelope-from ); Mon, 19 May 2025 21:19:03 +0000 From: Fabiano Rosas To: Steve Sistare , qemu-devel@nongnu.org Cc: John Snow , Cleber Rosa , Eric Blake , Markus Armbruster , Paolo Bonzini , "Daniel P. Berrange" , Eduardo Habkost , Laurent Vivier , Steve Sistare Subject: Re: [PATCH V2 0/5] fast qom tree get In-Reply-To: <1747057635-124298-1-git-send-email-steven.sistare@oracle.com> References: <1747057635-124298-1-git-send-email-steven.sistare@oracle.com> Date: Mon, 19 May 2025 18:19:00 -0300 Message-ID: <878qms70zf.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain X-Spamd-Result: default: False [-1.30 / 50.00]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-0.998]; MIME_GOOD(-0.10)[text/plain]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; MISSING_XM_UA(0.00)[]; MIME_TRACE(0.00)[0:+]; RCPT_COUNT_SEVEN(0.00)[11]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FUZZY_BLOCKED(0.00)[rspamd.com]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:email, suse.de:mid, qom.py:url, oracle.com:email] Received-SPF: pass client-ip=2a07:de40:b251:101:10:150:64:1; envelope-from=farosas@suse.de; helo=smtp-out1.suse.de 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 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. > > To reduce this cost, consider QAPI calls that fetch more information in > each call: > * qom-list-get: given a path, return a list of properties and values. > * qom-list-getv: given a list of paths, return a list of properties and > values for each path. > * qom-tree-get: given a path, return all descendant nodes rooted at that > path, with properties and values for each. > > In all cases, a returned property is represented by ObjectPropertyValue, > with fields name, type, and value. If an error occurs when reading a value > the value field is omitted. Thus an error for one property will not cause a > bulk fetch operation to fail. > > To evaluate each method, I modified scripts/qmp/qom-tree to use the method, > verified all methods produce the same output, and timed each using: > > qemu-system-x86_64 -display none \ > -chardev socket,id=monitor0,path=/tmp/vm1.sock,server=on,wait=off \ > -mon monitor0,mode=control & > > time qom-tree -s /tmp/vm1.sock > /dev/null > > I only measured once per method, but the variation is low after a warm up run. > The 'real - user - sys' column is a proxy for QEMU CPU time. > > method real(s) user(s) sys(s) (real - user - sys)(s) > qom-list / qom-get 2.048 0.932 0.057 1.059 > qom-list-get 0.402 0.230 0.029 0.143 > qom-list-getv 0.200 0.132 0.015 0.053 > qom-tree-get 0.143 0.123 0.012 0.008 > > qom-tree-get is the clear winner, reducing elapsed time by a factor of 14X, > and reducing QEMU CPU time by 132X. > > qom-list-getv is slower when fetching the entire tree, but can beat > qom-tree-get when only a subset of the tree needs to be fetched (not shown). > qom-list-get is shown for comparison only, and is not included in this series. > > Changes in V2: > * removed "qom: qom_resolve_path", which was pulled separately > * dropped the error member > * fixed missing _list_tree in qom.py > * updated 10.0 to 10.1 > > Steve Sistare (5): > qom: qom-tree-get > python: use qom-tree-get > tests/qtest/qom-test: unit test for qom-tree-get > qom: qom-list-getv > tests/qtest/qom-test: unit test for qom-list-getv > > python/qemu/utils/qom.py | 36 ++++++------- > python/qemu/utils/qom_common.py | 48 +++++++++++++++++ > qapi/qom.json | 90 ++++++++++++++++++++++++++++++++ > qom/qom-qmp-cmds.c | 112 +++++++++++++++++++++++++++++++++++++++ > tests/qtest/qom-test.c | 113 ++++++++++++++++++++++++++++++++++++++++ > 5 files changed, 381 insertions(+), 18 deletions(-) > > base-commit: 7be29f2f1a3f5b037d27eedbd5df9f441e8c8c16 Acked-by: Fabiano Rosas