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 0AD61C433F5 for ; Wed, 19 Jan 2022 12:25:44 +0000 (UTC) Received: from localhost ([::1]:55688 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nAA22-0008RH-TC for qemu-devel@archiver.kernel.org; Wed, 19 Jan 2022 07:25:42 -0500 Received: from eggs.gnu.org ([209.51.188.92]:40414) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nA9ua-0001NB-I4 for qemu-devel@nongnu.org; Wed, 19 Jan 2022 07:18:04 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:51420) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nA9uV-0006Eh-EK for qemu-devel@nongnu.org; Wed, 19 Jan 2022 07:17:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1642594664; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=THvdfQIVsiaAP6VP7w930JAvCLv5OuCQmP6xSqbh8G0=; b=JjZ/wvqUD8wpgYvi+j3zh5q5FdIYDX5242tJoWtWFFfA3/c4371hUswqKphxUpaP8DP4Ql oUsTtRJa+fkP/HU4oUesuy4E31fpNMvkXk5qDQdr31xPqYBDBH7M98ZQmNnJtfzmXnHoU7 +gCxaKK8BG8i2Ia7JuLKz/mG6yIQUS8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-568-5uxf3IHOP1WwaXtgJeGxzw-1; Wed, 19 Jan 2022 07:17:42 -0500 X-MC-Unique: 5uxf3IHOP1WwaXtgJeGxzw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6FF8883DD22; Wed, 19 Jan 2022 12:17:39 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-112-16.ams2.redhat.com [10.36.112.16]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D06587B9E8; Wed, 19 Jan 2022 12:16:40 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id C6D52113865F; Wed, 19 Jan 2022 13:16:38 +0100 (CET) From: Markus Armbruster To: huangy81@chinatelecom.cn Subject: Re: [PATCH v11 3/4] softmmu/dirtylimit: implement virtual CPU throttle References: <0381e32c2cc70613613aaa284b8e8c9760d6932f.1641316375.git.huangy81@chinatelecom.cn> Date: Wed, 19 Jan 2022 13:16:38 +0100 In-Reply-To: <0381e32c2cc70613613aaa284b8e8c9760d6932f.1641316375.git.huangy81@chinatelecom.cn> (huangy's message of "Wed, 5 Jan 2022 01:14:08 +0800") Message-ID: <878rvb3opl.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=armbru@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable 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: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.7, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=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: , Cc: Eduardo Habkost , David Hildenbrand , Juan Quintela , Richard Henderson , qemu-devel , Peter Xu , "Dr. David Alan Gilbert" , Paolo Bonzini , Philippe =?utf-8?Q?Mathieu-Daud?= =?utf-8?Q?=C3=A9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" huangy81@chinatelecom.cn writes: > From: Hyman Huang(=E9=BB=84=E5=8B=87) > > Setup a negative feedback system when vCPU thread > handling KVM_EXIT_DIRTY_RING_FULL exit by introducing > throttle_us_per_full field in struct CPUState. Sleep > throttle_us_per_full microseconds to throttle vCPU > if dirtylimit is enabled. > > Start a thread to track current dirty page rates and > tune the throttle_us_per_full dynamically untill current > dirty page rate reach the quota. > > Introduce the util function in the header for dirtylimit > implementation. > > Signed-off-by: Hyman Huang(=E9=BB=84=E5=8B=87) [...] > diff --git a/qapi/migration.json b/qapi/migration.json > index bbfd48c..ac5fa56 100644 > --- a/qapi/migration.json > +++ b/qapi/migration.json > @@ -1850,6 +1850,25 @@ > { 'command': 'query-dirty-rate', 'returns': 'DirtyRateInfo' } > =20 > ## > +# @DirtyLimitInfo: > +# > +# Dirty page rate limit information of virtual CPU. > +# > +# @cpu-index: index of virtual CPU. > +# > +# @limit-rate: upper limit of dirty page rate for virtual CPU. Lacks a unit. Is it bytes per second? pages per second? If I understand your code correctly, zero means unlimited. This is undocumented. Please document it. Something like "0 means unlimited" should do. > +# > +# @current-rate: current dirty page rate for virtual CPU. > +# > +# Since: 7.0 > +# > +## > +{ 'struct': 'DirtyLimitInfo', > + 'data': { 'cpu-index': 'int', > + 'limit-rate': 'int64', > + 'current-rate': 'int64' } } The next patch uses 'uint64' for set-vcpu-dirty-limit argument dirty-rate. Why signed here? > + > +## > # @snapshot-save: > # > # Save a VM snapshot [...]