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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EBAE5C41621 for ; Tue, 24 Mar 2020 18:40:18 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C95ED2076F for ; Tue, 24 Mar 2020 18:40:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C95ED2076F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xen.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1jGoT1-0005zu-DC; Tue, 24 Mar 2020 18:39:59 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1jGoSz-0005zp-QN for xen-devel@lists.xenproject.org; Tue, 24 Mar 2020 18:39:57 +0000 X-Inumbo-ID: dbf4b03a-6dfe-11ea-92cf-bc764e2007e4 Received: from mail-ed1-f67.google.com (unknown [209.85.208.67]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id dbf4b03a-6dfe-11ea-92cf-bc764e2007e4; Tue, 24 Mar 2020 18:39:57 +0000 (UTC) Received: by mail-ed1-f67.google.com with SMTP id b18so21970378edu.3 for ; Tue, 24 Mar 2020 11:39:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=9gHNtont17j3LM8qcOSXxPQPhDEII0lSFQG030PRrFc=; b=Z6q7liynohoz8paLMjsgRTkbMXIjaJnwbnexnNYkN31fAN7P5A9ALCBDBk9cIVOHf0 ZZDLBDZ7MKj0U6pmIizv00AG/Iemm02F4z4suXknK2Y3oqkujjje+Nuww12lHirTONDP bSXZ+sD9WBCRVIoOCqu1jCyw+3PwpN8EbJUNuFKN9TIyurT4fOqnKzfkYvz/Lei6SiUs xaa9yc/tLAZL4gEY6B1Evh4eoAir0Yii8Gu0k3u9KV2eu8y535ESZeBMxU/iexInTKrt r0MEBeEPQmv0GuaHnpDvS/I5wsJpsSWsLD/9FsGofN8wQn6H8QEV7sV0FodXfllF78hK Nh6w== X-Gm-Message-State: ANhLgQ2kKatwaCSGTPkf1c9KpDBUEmCI7hpHm+TU1odACg25zSzz4dND UkUfP+jIKvrJoIruf4JynmU= X-Google-Smtp-Source: ADFU+vvzTuFr+WLmWvXOGCxmA1kAiIOdmxsEoBinkZB0ir4HAZrg1p5zBWo11qB0OluXpCRrfhQ6YQ== X-Received: by 2002:a50:cd5a:: with SMTP id d26mr28929506edj.65.1585075196306; Tue, 24 Mar 2020 11:39:56 -0700 (PDT) Received: from a483e7b01a66.ant.amazon.com (54-240-197-224.amazon.com. [54.240.197.224]) by smtp.gmail.com with ESMTPSA id k9sm1399113edl.35.2020.03.24.11.39.55 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 24 Mar 2020 11:39:55 -0700 (PDT) To: Jan Beulich , Hongyan Xia References: <37dcd2d8-8ffe-a58e-4c7a-6dafc935b1c1@suse.com> From: Julien Grall Message-ID: <94abc4e0-b11e-df0f-3e3c-c3a61d87c63a@xen.org> Date: Tue, 24 Mar 2020 18:39:54 +0000 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <37dcd2d8-8ffe-a58e-4c7a-6dafc935b1c1@suse.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Subject: Re: [Xen-devel] [PATCH] Revert "domctl: improve locking during domain destruction" X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Stefano Stabellini , Wei Liu , Andrew Cooper , Ian Jackson , George Dunlap , xen-devel@lists.xenproject.org Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On 24/03/2020 16:13, Jan Beulich wrote: > On 24.03.2020 16:21, Hongyan Xia wrote: >> From: Hongyan Xia >> In contrast, >> after dropping that commit, parallel domain destructions will just fail >> to take the domctl lock, creating a hypercall continuation and backing >> off immediately, allowing the thread that holds the lock to destroy a >> domain much more quickly and allowing backed-off threads to process >> events and irqs. >> >> On a 144-core server with 4TiB of memory, destroying 32 guests (each >> with 4 vcpus and 122GiB memory) simultaneously takes: >> >> before the revert: 29 minutes >> after the revert: 6 minutes > > This wants comparing against numbers demonstrating the bad effects of > the global domctl lock. Iirc they were quite a bit higher than 6 min, > perhaps depending on guest properties. Your original commit message doesn't contain any clue in which cases the domctl lock was an issue. So please provide information on the setups you think it will make it worse. Cheers, -- Julien Grall