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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_MUTT autolearn=ham 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 32157C04AB4 for ; Tue, 14 May 2019 15:20:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 05D4721473 for ; Tue, 14 May 2019 15:20:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="IT5FIib4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726447AbfENPUg (ORCPT ); Tue, 14 May 2019 11:20:36 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:47472 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726025AbfENPUg (ORCPT ); Tue, 14 May 2019 11:20:36 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x4EFItQ9026749; Tue, 14 May 2019 15:20:11 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2018-07-02; bh=TAKl7MVPjAyeW4pysbmsSHellOYUJq5rtojHmkQ8ztM=; b=IT5FIib4qMNUvf3xltPxmxaRRwANwyP/z12rU6yPZXdhhETRaPilGrFbg0o+KtneSXn7 kk7cM/yIRL9Hx29OoROgWdRsP2F7m4G7dQminqB9w6jCo6orHLP93besbXIw1dnFSHLs XrFy9n4Rhcvr4TLSqTgR/uquEP/1BrdxrPnznS8gj0XhC6EcHzlqrk0ZqqJf7lIuCzGE nE3QlU4i4lK6FclhmRddDQ9ZK01sd9cBvCKT35Q/h+1NRj3In0g1yG8HTyFNsmjLYuN8 pWAtuhVln9NOjzlPlAgdQpmF5bnN+9Z0teSc2aKJn2rzKiZxbYdLb2hLWWc5p19OcTPf xQ== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2130.oracle.com with ESMTP id 2sdnttptps-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 14 May 2019 15:20:11 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x4EFJHbp053648; Tue, 14 May 2019 15:20:10 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserp3030.oracle.com with ESMTP id 2sdmeb4ynx-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 14 May 2019 15:20:10 +0000 Received: from abhmp0009.oracle.com (abhmp0009.oracle.com [141.146.116.15]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x4EFK9WY018964; Tue, 14 May 2019 15:20:10 GMT Received: from char.us.oracle.com (/10.152.32.25) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 14 May 2019 08:20:09 -0700 Received: by char.us.oracle.com (Postfix, from userid 1000) id EA8AB6A010B; Tue, 14 May 2019 11:20:15 -0400 (EDT) Date: Tue, 14 May 2019 11:20:15 -0400 From: Konrad Rzeszutek Wilk To: Marcelo Tosatti Cc: Wanpeng Li , kvm-devel , LKML , Thomas Gleixner , Ingo Molnar , Andrea Arcangeli , Bandan Das , Paolo Bonzini Subject: Re: [PATCH] sched: introduce configurable delay before entering idle Message-ID: <20190514152015.GM20906@char.us.oracle.com> References: <20190507185647.GA29409@amt.cnet> <20190514135022.GD4392@amt.cnet> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190514135022.GD4392@amt.cnet> User-Agent: Mutt/1.9.1 (2017-09-22) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9256 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=679 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905140108 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9256 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=709 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905140108 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 14, 2019 at 10:50:23AM -0300, Marcelo Tosatti wrote: > On Mon, May 13, 2019 at 05:20:37PM +0800, Wanpeng Li wrote: > > On Wed, 8 May 2019 at 02:57, Marcelo Tosatti wrote: > > > > > > > > > Certain workloads perform poorly on KVM compared to baremetal > > > due to baremetal's ability to perform mwait on NEED_RESCHED > > > bit of task flags (therefore skipping the IPI). > > > > KVM supports expose mwait to the guest, if it can solve this? > > > > Regards, > > Wanpeng Li > > Unfortunately mwait in guest is not feasible (uncompatible with multiple > guests). Checking whether a paravirt solution is possible. There is the obvious problem with that the guest can be malicious and provide via the paravirt solution bogus data. That is it expose 0% CPU usage but in reality be mining and using 100%.