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 B7F29C3A59F for ; Thu, 29 Aug 2019 12:53:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 989DF23403 for ; Thu, 29 Aug 2019 12:53:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727063AbfH2Mx0 (ORCPT ); Thu, 29 Aug 2019 08:53:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36726 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725990AbfH2MxZ (ORCPT ); Thu, 29 Aug 2019 08:53:25 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7C68B8AB25B; Thu, 29 Aug 2019 12:53:25 +0000 (UTC) Received: from amt.cnet (ovpn-112-4.gru2.redhat.com [10.97.112.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 001706060D; Thu, 29 Aug 2019 12:53:22 +0000 (UTC) Received: from amt.cnet (localhost [127.0.0.1]) by amt.cnet (Postfix) with ESMTP id 61ACB10513F; Thu, 29 Aug 2019 09:53:06 -0300 (BRT) Received: (from marcelo@localhost) by amt.cnet (8.14.7/8.14.7/Submit) id x7TCr42i012268; Thu, 29 Aug 2019 09:53:04 -0300 Date: Thu, 29 Aug 2019 09:53:04 -0300 From: Marcelo Tosatti To: Wanpeng Li Cc: "Rafael J. Wysocki" , Paolo Bonzini , "Rafael J. Wysocki" , LKML , kvm , Radim =?utf-8?B?S3LEjW3DocWZ?= , Linux PM , "Michael S. Tsirkin" Subject: Re: [PATCH] cpuidle-haltpoll: Enable kvm guest polling when dedicated physical CPUs are available Message-ID: <20190829125304.GA12214@amt.cnet> References: <20190803202058.GA9316@amt.cnet> <20190826204045.GA24697@amt.cnet> <20190828143916.GA13725@amt.cnet> <20190829120422.GC4949@amt.cnet> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.68]); Thu, 29 Aug 2019 12:53:25 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Thu, Aug 29, 2019 at 08:16:41PM +0800, Wanpeng Li wrote: > > Current situation regarding haltpoll driver is: > > > > overcommit group: haltpoll driver is not loaded by default, they are > > happy. > > > > non overcommit group: boots without "realtime hints" flag, loads haltpoll driver, > > happy. > > > > Situation with patch above: > > > > overcommit group: haltpoll driver is not loaded by default, they are > > happy. > > > > non overcommit group: boots without "realtime hints" flag, haltpoll driver > > cannot be loaded. > > non overcommit group, if they don't care latency/performance, they > don't need to enable haltpoll, "realtime hints" etc. Otherwise, they > should better tune. As mentioned before, "being overcommitted" is a property which is transitional. A static true/false scheme reflects this poorly. Therefore the OS should detect it and act accordingly.